PLEASE NOTE: THIS PROJECT IS NOT SCIENTIFIC. IT IS A HOBBY.
"I was looking for information on an old mammal and found this lot. What is this
project?"
It's got lots of information on old mammals. For a short bit of background information, see
here.
This directory features multituberculates which
are mostly post-Mesozoic; the products of a post Cretaceous radiation.
As an exercise in book-keeping, this directory has been one of the most challenging. In
terms of internet material, however, it's somewhat impoverished. There are plenty of fossil
inventories on North American locations, but readable articles and pictures are unfortunately
rare. There has been some improvement over the last year, but more would be welcome.
This directory was originally entitled Cimolodontidae and Ptilodontidae. Neoplagiaulacinae
and Ptilodontinae were treated as subfamilies of the latter. |
A. Neoplagiaulacidae & Neoliotomus B.
Ptilodontidae C. Cimolodontidae
| A. NEOPLAGIAULACIDAE & NEOLIOTOMUS |
| Taxon: Neoplagiaulacidae Ameghino F, 1890
Reference: Ameghino (1890), Los plagiaulácidos Argentinos y sus relaciones zoológicas,
geológicas y geográficas. Boletin del Instituto Geográfico Argentino, 11, p.143-208.
The following is based upon my reading of the text from Scott, 2005. Any page numbers
mentioned are in Roman numerals, and these don't correspond at all with those in the original
publication.
Neoplagis were relatively late multituberculates which flourished in the Paleocene (p.i).,
and then at least largely died out by the Eocene. (Rare Oligocene occurrences are sometimes
cited.) Most remains are poorly preserved fossils from North America, and poor preservation
means sorting out this from that can be difficult to impossible. For example, the species
rich genus of Neoplagiaulax probably contains various
neoplagis which, although broadly similar as far as they're known, don't all belong in the
same genus. Recognising that is relatively straightforward. Finding reliable characters
to resolve the tangle is a different matter.
Despite being among the latest multis, the family persevered with some ptilodontoid
plesiomorphies. Various groups of multis developed an
unusual mammalian tooth enamel organised into large prisms. In contrast, neoplagis
persisted with microprismatic enamel. The lower incisor
was thin and pointed forwards. The lower p4 premolar was
large and equipped with many cusps. In some ways these were traditionalists with little
appetite for innovations to exploit new resources, and this was in contrast to more
adventurous relatives; eg. taeniolabids.
They may not have been followers of the latest fashions, but neoplagis were far from old
hat. They were numerous in terms of individuals and species, and they out-survived
multi-modernists. As their demise appears to coincide with the rise of
placental rodents with presumably similar tastes, that
may well explain their downfall.
Difficult conservatives
Neoplagis were a dentally conservative bunch, as they don't display all too much refinement
of the inherited equipment (p.xxvi). This creates problems for distinguishing them from
one another, especially when only isolated remains are available. For example, there's
little difference between the upper molars of
Neoplagiaulax serrator and N. hunteri. In the
absence of further evidence, upper molars could sensibly be assigned to other species.
Those of N. serrator would also qualify for Ectopodys
powelli (based on differing criteria). It's the fourth premolars (both upper and lower)
which provide more clarity, and most especially the lower one.
Additional notes
Neoplagiaulacinae Ameghino, 1890 has been seen
as a sub-family within Ptilodontidae Cope, 1887, (McKenna & Bell, 1997). More recent
thinking has it as a family. Synonyms are Ectypodidae Sloan & Van Valen, 1965 and
Ectypodontidae Sloan & Van Valen, 1965.
At this juncture, you might like to consult a Welsh telephone directory. It'll contain many
names, a great number of which will be Jones. This section's a bit similar. Many names for
teeth, some of which have been classified, re-classified and re-re-classified, etc. The
exact affinities of Neoliotomus are not clear. It doesn't seem to be part of this
taxon, though it's thought to fit somewhere within
Ptilodontoidea. Somewhat uncertain are the affinities of a genus published in 2003,
Fractinus. I placed it here because it has some reported similarity with
Xanclomys. As Scott, 2005 includes it in the family, it appears I was right to do
so.
Genera: Cernaysia, Charlesmooria (= Ectypodus),
Ectypodus (partly = Neoplagiaulax &
Parectypodus), Eucosmodon (partly = Neoliotomus),
Fractinus, Krauseia,
Mesodma, Mesodmops,
Mimetodon, Neoliotomus,
Neoplagiaulax, Parectypodus,
Xanclomys, Xyronomys,
other reports
Time-Line:
Eocene: Ectypodus, Mesodmops, Neoliotomus, Parectypodus
Paleocene: Cernaysia, Ectypodus, Fractinus, Mesodma,
Mimetodon, Neoliotomus, Neoplagiaulax, Parectypodus,
Xanclomys, Xyronomys
Upper Cretaceous: Mesodma |
| Genus: Cernaysia Vianey-Liaud
M, 1986
'from Cernay'
Aka: Carnaysia |
| Species: | Cernaysia davidi Vianey-Liaud M, 1986 |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Cernaysia manueli Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Upper Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Genus: Ectypodus Matthew WD
& Granger W, 1921
Aka: Charlesmooria ('for Charles Moor') Kühne, 1969; Parectypodus (partly)
Remarks: Messy. McKenna & Bell (1997) cites material from the Paleocene and
Eocene of Europe. According to Smith & Smith, 2004, the genus occurs in Ypresian
strata in France. Additionally, the original remains used for the establishment
of C. childei were found near London.
Reference: Matthew & Granger (1921), New genera of Paleocene mammals. American Museum
Novitates, 13, p.1-7.
| Reassigned species: ?E. aphronorus Sloan, 1987 see
Parectypodus sylviae; E. cochranensis Russell, 1967 see
Anconodon cochranensis; E.? grangeri
Simpson, 1935 see Neoplagiaulax grangeri;
E. hazeni Jepsen, 1940 see Neoplagiaulax
hazeni; cf. E. haueni (Jepsen, 1940) see
Ptilodus gnomus; E. hunteri Simpson, 1936 see
Neoplagiaulax hunteri; E. laytoni
Jepsen, 1940 see Parectypodus laytoni; E.
macrotomeus Wilson, 1956 see Neoplagiaulax
macrotomeus; E. russelli Simpson, 1935 see
Anconodon cochranensis; E.? silberlingi Simpson, 1935 see
Mimetodon silberlingi; E. simpsoni Jepsen,
1940 see Parectypodus simpsoni; E.
sinclairi Simpson, 1935 see Parectypodus
sinclairi; E. sloani see Parectypodus
sloani; E. sylviae Rigby, 1980 see
Parectypodus sylviae | |
| Species: | Ectypodus musculus Matthew WD & Granger, 1921
|
| Place: | Mason Pocket, Colorado |
| Country: | USA |
| Age: | Torrejonian, Upper Paleocene |
| Remarks: | A macho version, weighing in at around 30g. |
| Reference: | Matthew & Granger (1921), New genera of Paleocene mammals.
American Museum Novitates, 13, p.1-7. |
| Species: | Ectypodus powelli Jepsen GL, 1940 |
| Place: | Princeton Quarry, Wyoming |
| Country: | USA |
| Age: | Torrejonian-Tiffanian, Middle-Upper Paleocene |
| Remarks: |
Holotype and other specimens at the Peabody, Yale. At least some
of this material has been referred to Microcosmodon conus Jepsen, 1930. Guestimate,
20g. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Proceedings of the American Philosophical Society, 83, p.217-340. |
| Species: | Ectypodus tardus (Jepsen GL, 1930) McKenna MC,
1960 |
| Aka: | Parectypodus tardus Jepsen, 1930 |
| Place: | Colorado & Wyoming |
| Country: | USA |
| Age: | Wasatchian, Eocene |
| Remarks: | A descendant of E. powelli, (Burkitt JH).
Specimens presently studying at Yale University. Weighed about 15g. |
| References: | Jepsen (1930), New vertebrate fossils from the lower Eocene
of the Bighorn Basin, Wyoming. Proceedings of the American Philosophical Society, 69,
p.117-131. |
| McKenna (1960), Fossil Mammalia from the early Wasatchian Four
Mile Fauna, Eocene of northwest Colorado, Univ. Calif. Pub. Geol. Sci. 37 (1), p.1-130.
|
| Species: | Ectypodus lovei (Sloan RE, 1966) Krishtlaka &
Black, 1975 |
| Aka: | Parectypodus lovei Sloan RE, 1966 |
| Place: | Saskatchewan & Wyoming |
| Country: | Canada & USA |
| Age: | Uintan-Chadronian, Upper Eocene |
| Remarks: | Weight circa 15g. |
| Reference: | |
| Species: | Ectypodus szalayi Sloan RE, 1981 |
| Place: | New Mexico & Gidley Quarry, Montana &
Wyoming |
| Country: | USA |
| Age: | Mid Paleocene |
| Remarks: | 15g of furry fun.
Similar fossils have been identified in the Alberta locations of
Who Nose? and Cochrane 1 (though the latter is
undescribed). The first mentioned site has yielded two lower
premolars, (p4s). Their crowns contain eleven serrations. These specimens have been
referred to cf. E szalayi, (Scott 2003, p.747). |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates
from the San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan
Basin paleontology. University of New Mexico Press, Alberquerque. |
| Species: | Ectypodus childei (Kühne WB, 1969) Krause
DW, 1982 |
| Aka: | Charlesmooria childei Kühne, 1969; Parectypodus
childei Sloan, 1981 |
| Place: | Abbey Wood, London & ?Wyoming |
| Country: | England & ?USA |
| Age: | Wasatchian, Eocene |
| Remarks: | The following is based upon my reading of
Kühne, 1969, and more thanks fly to the dedicated supplier. The study included the
establishment of Charlesmooria childei. I don't happen to have seen the
relevant papers by either Sloan or Krause.
Fossils Kühne assigned to Charlesmooria were confined to a right lower incisor
and one p4 premolar, and it may be thought that establishing a
taxon upon such a limited basis was rather hasty. That seems to have been the
view of the author. He considered this: "the bare minimum for a diagnosis", and
proceeded "reluctantly". This occurred due to: "bitter experience regarding 'Duchy
33'". If all you had available were the original description, then the meaning of
that could be baffling.
Some decoding and UK slang is called for
The background gen is that Kühne had earlier been gazumped. That fine piece of
slang pertains to the complex and stressful activity of house buying. The seller
and wannabe purchaser generally aren't entirely open in their communication, and
neither knows the full story from both perspectives. Finally, however, a provisional
agreement is reached. But, before pen can be set to paper to consummate the matter,
the vendor suddenly pulls out of the deal for unexplained reasons. The wannabe
purchaser is left smelling something fishy, and it is indeed a rat. They've very
likely just been gezumped. Somebody else put the spoiler on things be offering ten
grand more. Regardless of any pledges of eternal love and longing, the vendor leapt
into bed with them behind your back. You're left standing alone at the altar, your
bridal bouquet develops brewer's droop and suddenly you: "ain't got no home" (with
thanks to Guthrie, W).
Kühne had been gezumped in the Lower Jurassic of South Wales. There, he'd found a
single tooth from an unknown genus of mammal, and
felt naming it should wait until later. More fossils would presumably come to light,
and provide fuller information. That'd be the time to name names, and Duchy 33 was
fine for the while. Paleontological names are meant to be useful, not ornamental.
However, somebody else failed either to respect or appreciate the situation, or
perhaps both, and published the name of Kuehneon.
As it happens, the only known specimen has since gone astray. The so "honoured"
Professor Kühne appears to have been left spitting blood in fury, and he sure as
hell didn't intend being gezumped in the Eocene near London.
Needles in a haystack in the wood
The since abolished Greater London Council had responsibility for managing Abbey
Wood, and this place happens to have included a fossil locality dating from the
Lower Eocene (p.199). Its ancient fauna included molluscs and
vertebrates; typical Londoners such as fish,
turtles, a crocodile and a primate. Not much has since changed in the area. Today,
London remains a terrain covered by lush and varied tropical forest. Well, there
are some greenhouses at Kew. Anyway, the park authorities opened up access to Abbey
Wood after the Second World War, and fossil collectors and randy courting couples
were only too pleased to take advantage of the opportunities provided. Herr and
Frau Kühne were certainly among the first group for three days during September
1968, and no mention is given of the second group. The kind of fossil techniques
the Kühnes employed went slightly beyond scouring the surface of the ground, and
putting shells and scraps in an empty plastic (I happen to have some Eocene fossils
in front of me. These shells and scraps were picked up from a somewhat more
recent Eocene locality at Highcliffe, east of Bournemouth, and we collected them in
a leisurely manner a couple of months ago or, if you're reading this later,
earlier.)
The Kühne style wasn't in the least leisurely. They stripped the top soil from a
convenient place and then gathered up a little bit of sediment; less than half a
ton. They could see this stuff must've been interviewed previously on at least one
occasion, and any larger mammal fossils had already been removed. After applying a
process termed wet dressing, a water filled chip pan with a one centimetre mesh
came into play. That was used to sieve out stones and unwanted oysters (p.200) and,
submerged under water, a half cm meshed sieve allowed for the removal of soil and
sand. Somehow, they found time to work through the whole heap during their brief
visit, and reduced things down to a more portable 75 kilos of mostly mollusc.
Returning with it to Berlin, they then resorted to chemical warfare. A particular
acid dissolved the mollusc remains, and other groovy attacks separated out flint
and persistent sand. Those activities brought things done to a single kilo; half a
sugar bag in weight subdivided into four categories of size. All that was then
examined with the help of a microscope and vast reserves of patience, and a grand
total of six mammal teeth were found among the 0.8 to 2mm stuff. That was the sum
total, a 3-3 draw between multituberculates
and primates.
Kühne style fossil hunting went beyond established frontiers.
The marks of this beast
The p4 premolar is rather small at only 2.9mm long,
and its crown features eleven serrations. There's a row of vestigial cuspules to the
rear on the lingual side. Its companion
incisor manages a preserved length of 3.5mm but, as
there's breakage, some is missing. That has enamel restricted to a band on the
front. Kühne allocated both to the family of Eucosmodontidae, as then understood.
The premolar was too small to be included into Liotomus marshi,
known from France. L. m. is over twice the length and features 15 to 17
serrations. It was also too small in comparison to known American cousins, in
Kühne's opinion. In comparison to L. m., the relatively low number of
serrations is said to show: "its evolutionary level is lower..." (p.201).
Presumably, that means it's more basal despite being
later. I fell like adding a 'perhaps'.
A small squeak from a once mighty choir
From the Upper Jurassic onwards, northern hemisphere mammalian faunas were often
dominated by multis in terms of numbers. They remained diverse during the Paleocene,
and some even explored the possibilities afforded by large,
beaver-sized formats; animals of 25 kilos and more. However, while not entirely
unknown, they were rarities in Eocene faunas, and none seem to have survived beyond
that age. Reported Oligocene occurrences have been proposed in North America, but
they more probably were misdated.
The efforts of the Kühnes were partly directed against a bias n the known record;
size-ism. Surface collection is all well and good, and can be fun, but it tends to
result in a distorted picture filled with too many biggling. Most the global
population happen to be small. The Kühnes also demonstrated suitable techniques can
drag new knowledge from localities, which have already been actively worked by
various people for several decades; even from previously sampled deposits.
What they also found was an extension of multis into the European Eocene. This was
only the second known source from the Tertiary in the continent. "It is hoped that
a third locality yielding Tertiary multituberculates may be discovered in Europe
soon" (p.202). Several have since been added, but I don't happen to have an
inventory.
RIP multis
A likely explanation for the extinction of multis remains competition from new
placental groups; firstly from "condylarths"
and then rodents. Kühne has a couple of observations pertinent to the second group
on page 201. Rodents have ever-growing incisors with open roots whereas multis
never hit upon such things. Multis were also limited by relatively thin tooth
enamel, although I don't know if that's still valid. (It is, as far as I'm aware.)
He also states multis: "never develop the tooth-sharpening modus known in most other
mammalia which R.G. Every has aptly called 'thegosis'." As far as I understand
thegosis, it refers to sharpening as a by-product of use.
Charlesmooria
This generic name honours the nineteenth century microfossil pioneer, Charles Moore
of Bath. His experiences, methods and successes earned him the title of: "the
spiritual father of the writer's activities in England and Wales from 1937 onwards.
As for the holotype, none was specified in the paper. The lower premolar is
clearly the more informative specimen, and would've been the logical choice. The
two fossils described were donated to the Natural History Museum, London, and a
small piece of an upper premolar provided them with company. The trio received the
catalogue numbers of M26617, -18 and -19. As for the specific name, that honours V
Gordon-Childe for his efforts to more archaeology more scientific in its approach.
Additional notes
I read somewhere or other that the species was found in Wyoming, but I don't
presently know whether that's correct. The type fossil is certainly from near
London.
The junior synonym, Parectypodus childei, was reportedly originally referred
to P. lunatus, a citizen of Colorado. A 15g titch. |
| Reference: | Kühne WG (1969), A multituberculate from the Eocene of
the London Basin, Proceedings of the Geol. Society of London, 1658, p.199-202. |
| Species: | Ectypodus aphronorus Sloan RE, 1987 |
| Place: | Gidley Quarry, Montana & Wyoming |
| Country: | USA |
| Age: | Middle Paleocene |
| Remarks: | I've heard this is possibly a junior synonym of
Parectypodus sylviae, which began its career as E.. Scott, 2005 suggests
it's nevertheless a valid species of this genus. |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammals, rates
of sedimentation and evolution, p. 165-200. In J. E. Fassett and J. K. Rigby Jr. (eds.),
The Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado.
Geological Society of America Special Paper, 209. |
| Species: | Ectypodus elaphus Scott CS, 2005 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
This is a small species of Ectypodus (p.iv). The length of the lower p4
premolar is half that of E. musculus and 23% less
than for E. powelli and E. aphronorus, and the crown is also relatively low
(compared to E. m. and E. a.). The most similarities are shared with E.
szalayi and E. tardus. Again though, the crown is lower and less symmetrical
when viewed from the side. The first serration is also set lower, and the front of the
crown is steeper. Additionally, both cusp rows on p4s of E. szalayi have more
cusps. The retention of a p3 tooth is a contrast from both E. tardus and E.
childei.
Upper premolars
Some uppers have been assigned to the species, and most are P4 premolars. The numbers in
the 'three' cusp rows (labial to
lingual) are given as: (0)2:6:0. A pair of strong cusps is positioned towards the
front of the labial side, the middle row runs in a straight line and an internal row is
absent. The front of the tooth is supported by a root with a circular cross-section, while
its rear partner looks more like it's been squashed from both sides; ie. it's laterally
compressed.
Upper molar
Only the M1 is known; cusp formula 7:9:5. In size and structure, this tooth is rather like
the generally earlier Mesodma pygmaea, although this version
is a bit bigger and the lingual cusp row is longer. The cusps of the central row are shaped
like pyramids rather than crescents.
Lower jaw
The type fossil (and several colleagues) provide information about the
dentary (p.v). The available material is much as could be expected for a neoplagi.
Towards the back, the coronoid process was presumably tall, and the condyle (the lower
element of the jaw-skull joint) was broad and oval in shape.
Lower premolars
The p3 is a pathetic thing which was granted sanctuary in a concave area at the base of the
p4; the sole lower premolar interested in working for a living.
Seen from the side, the crown of the p4 is of a moderate height, and the front and rear
slopes aren't as symmetrical as for other species of the genus. As well as the aforementioned
concavity, the front root is also grooved so as to provide room for the anterior premolar.
The crest of this tooth generally bears eleven serrations, although some specimens restrict
their enthusiasm to ten. These become larger and stronger progressively towards the rear.
Ridges run down both sides of the tooth from the serrations, and they become fainter. The
final serration has no such ridges.
Lower molars
The cusp formula of m1s is 8:4 (buccal -
lingual), and the outline of the crown is near to rectangular. The cusps rows drift
away from each other towards the rear, and a fairly deep valley lies between them. The
crescent-shaped buccal cusps are lower than the pyramid-shaped lingual ones. These
molars are very similar to those of E. tardus from the
Eocene (p.vi). They're also rather like the equivalent teeth of Mesodma pygmaeae,
but they're a bit longer and have at least two more buccal cusps.
The sole specimen of an m2 has a cusp formula of 4:2. It's also similar to Ectypodus
and Mesodma pygmaea, but it's a bit wider than the latter.
Affinities
E. elaphus seems most similar to E. szalayi in terms of the p4. The average
length is close (2.63 against 2.8mm respectively), and both forms favour eleven serrations.
The differences include the lower and less symmetrical crown for the new species.
The pair appear to be basal members of the genus, and they
also share features with more primitive neoplagis such as Mesodma
(p.vii). Although later, Scott concludes E. elaphus is possibly the less derived of
the duo.
Holotype
The type fossil, UAL VP 45994, studies at the University of Alberta, Edmonton. It's a
partial left dentary with premolars 3 and 4, and
alveoli for the incisor and two molars. 'Elaphos' is Greek for 'deer' and 'stag',
and this honours the city of Red Deer, which is close to the fossil locality. |
| Reference: | Scott (2005), New neoplagiaulacid multituberculates (Mammalia,
Allotheria) from the Paleocene of Alberta, Canada, Journal of Paleontology, 79(6),
p.1189-1213. |
| Species: | ?Ectypodus clemensi |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Paleocene |
| Remarks: |
The Peabody, Yale has a cast of an E. cf. clemensi,
collected in 1977. Common sense suggests this is Krauseia clemensi. |
| Reference: | |
Genus: Fractinus Higgins P, 2003
'broken into pieces'
Remarks: The generic names refers to the locality, which is called The Breaks. |
| Species: | Fractinus palmorum Higgins P, 2003 |
| Place: |
The Breaks, Wyoming |
| Country: | USA |
| Age: | lower Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of
Higgins, 2003a.
The northeastern corner of the Hanna Basin contains an area of badlands known as The
Breaks, (p.468). So far, remains of 72 separate mammalian species have been identified
from the locality, but only this one has not already been described from elsewhere. 17
of these species are multis, but they account for over half of all the specimens, (426 out
of 811). This material is in the Collection of Fossil Vertebrates of the University of
Wyoming.
Hardly a mouth full
Remains are presently restricted to one and a bit teeth. These are the spectacular lower
premolars. However, they're unusual for multis. Unlike
the equivalents known from most members of Ptilodontidae, Cimolodontidae and
Eucosmodontidae, they don't have as many serrations on the cutting edge, (approximately
five). These are also more rounded than usual, and start further back. The
ptilodontoidean which is most similar is Xanclomys, and that's my logic for placing
the genus in this section. It isn't intended to say anything concerning the actual
affinities of this critter. However, it also differs from Xanclomys. It has less
serrations, and they're found in a single line. It seems to significantly differ from
everything in Multidom, though there is a superficial resemblance in shape to Jurassic
multis such as Psalodon. It was a middling-sized representative of the order.
Techniques for working this locality were mainly underwater screen-washing and surface
crawling, which sounds potential painful on the knees in a rugged landscape.
Holotype
The type fossil is a lower, left premolar (p4) with a length of slightly less than 5mm.
It's in the Wyoming collection and is affectionately known as UW 27063. It enjoys the
company of one other fragment of a p4, which was found about 25m away. The species name is
in honour of Burt and Kaylyn Palm, who kindly permitted access to these sites on their
property.
Additional notes
Scott, 2005 includes the genus within Neoplagiaulacidae (p.i). |
| Reference: | Higgins (2003), A New Species of Paleocene Multituberculate
(Mammalia: Allotheria) from the Hanna Basin, South-Central Wyoming. Journal of Vertebrate
Paleontology, 23 (2), p.468-470. |
| Genus: Krauseia Vianey-Liaud
M, 1986
'for Krause'
Aka: Parectypodus (partly)
Reference: Vianey-Liaud (1986), Les Multituberculés Thanétiens de France, et leurs
rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool. Stratigr.
191 p.85-171, 3 plates. |
| Species: | Krauseia clemensi (Sloan RE, 1981) Vianey-Liaud M,
1986 |
| Aka: | Parectypodus clemensi Sloan RE, 1981 |
| Place: | San Juan Basin, New Mexico &
Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | An approximate weight for P. clemensi is
one standard mouse, 25g. |
| References: | Sloan (1981), Systematics of Paleocene multituberculates from
the San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan
Basin paleontology. University of New Mexico Press, Alberquerque. |
| Vianey-Liaud (1986), Les multituberculés Thanétians de France, et
leurs rapports avec les multituberculés Nord-Américains, Palaeontographica Abteilung A
Palaeozoologie-Stratigraphie, v.191, p.85-171. |
| Genus: Mesodma Jepsen
GL, 1940
Aka: Cimexomys (partly); Cimolodon (partly); Cimolomys (partly);
Halodon Marsh, 1889? (partly); Parectypodus (partly); Ptilodus
(partly)
Remarks: A variety of further material has been reported. This looks like a messy genus.
I’ll try to avoid confusing things further. A heap of unnamed specimens also crop up here
and there. I’ll ignore them until they’re properly introduced. One example is a lower
premolar (p4) from North Dakota, (Hunter & Pearson
1996, p.635-636): "The specimen is within the size range for p4 length of M.
thompsoni Clemens 1964, M. garfieldensis Archibald 1982 and M. ambigua
Jepsen 1940, although it would be unusually large for the first two species."
An early bird
A Santonian presence has been reported by Eaton JG, 2005, from the Straight Cliffs Formation
of Utah. This would be the oldest representative of the genus. The abstract is linked to
the entry for Cimolodon foxi.
Hell Creek, Montana
Lofgren, 1995 reports that something like 2,200 specimens of teeth and jaw fragments of this
genus have been recovered from the Hell Creek Formation (p.78). At the time, they hadn't
been referred to any particular species. His work is an examination of geological conditions
and mammal fossils from localities at Cretaceous-Paleocene,
McGuire Creek.
| Reassigned species: M.? ambigua? Jepsen, 1940 see
?Cimexomys gratus; M. silberlingi
see Mimetodon silberlingi | |
| Species: | Mesodma ambigua Jepsen GL, 1940 |
| Place: | Mantua Lentil, Wyoming, Montana &
Colorado |
| Country: | USA |
| Age: | Maastrichtian-Puercan, Upper Cretaceous-Paleocene |
| Remarks: | Descendant of M. thompsoni, (Burkitt, JH).
Material at Yale, where M.? a.? became ?Cimexomys gratus. They also have the
type fossil. Weighed about 55g, two slightly fat mice. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation, Park
County, Wyoming, Proceedings of the American Philosophical Society, 83(2), p.217-341. |
| Species: | Mesodma formosa (Marsh OC, 1889) Clemens, 1964a
|
| Aka: | Cimolomys formosus Osborn HF, 1891; Cimolomys gracilis
(Marsh, 1889) Simpson, 1929; Halodon formosus Marsh, 1889; M. formosus;
Ptilodus formosus Gidley, 1909 |
| Place: | Montana New Mexico, South Dakota, ?Utah,
Wyoming & Alberta, Saskatchewan |
| Country: | USA & Canada |
| Age: | Upper Cretaceous (Campanian - Maas.) - Paleocene (Puercan) |
| Remarks: | Osborn, 1893 (p.315) reveals that Halodon
formosus had been established for lower premolars (p4s). At the time, he referred the
species to Ptilodus, which is now restricted to the Paleocene. Marsh based
Cimolomys gracilis on upper molars (M1) (p.316). These have three rows of cusps
running along the complete length of the crown (p.317).
Additional notes
Possibly also Utah. The holotype is at Yale and
a suggested weight is a
fat-moused 30g. South Dakota is mentioned by Foote et al, 1999.
Some material which seems at least similar to this species has been recovered from the
El Gallo Formation of Mexico, (Weil 1999, p.87). |
| References: | Marsh (1889), Discovery of Cretaceous Mammalia. Am. J. Sci. (3)
xxxviii, p.177-180. |
| Osborn (1891); A review of the Cretaceous Mammalia. Proc. Acad. Nat. Sci.,
Phila.: 124 - 135. |
| Simpson (1929), American Mesozoic Mammalia. Mem. Peabody Mus. Nat. Hist. iii (i):
p.1-235. |
| Species: | Mesodma primaeva (Lambe, 1902) Clemens,
1964a |
| Aka: | Cimolomys primaevus Simpson, 1929; Mesodma
primaevus Clemens, 1963; Parectypodus primaeva;
Ptilodus primaevus Lambe, 1902 |
| Place: | Oldman Formation & Montana, Wyoming |
| Country: | Canada & USA |
| Age: | Campanian, Upper Cretaceous - Lower Paleocene |
| Remarks: | The following is largely based upon my
reading of Sahni, 1972, a study concerned with vertebrates from the Judith River
Formation of Montana.
A dimensions ditty
M. primaeva is about the same size as M. thompsoni (p.367), larger when
compared to M. formosa but gets beaten in this regard by M.
ambigua.
Lower incisors
Several referred several of these teeth to the species. They were the right size
and much like incisors identified previously.
Lower premolars
The average length of p4s from the Judith River Formation, was 3.0mm, and
the blade of the tooth has 11 serrations. On the labial
side short ridges are associated with the first two serrations, and they run towards
ridges descending from the others. The blade is high and nearly symmeticral, with
its highest point achieved by the fourth or fifth serration. A cavity is found at
the front of the tooth, and this provided housing for the pathetic p3. All cavity
walls are thickly enamelled excepting for the rear one.
Ridges also occur on the lingual face of the crown.
The first is longer than or equal to the second, and the longest ridge of all is
generally the fifth (although sometimes it's the fourth or sixth). The crown has
the support of two roots, with the first one being the larger (p.369).
Lower molars
There's a difficulty with isolated m1s, and that is differentiating them from the
corresponding teeth of Cimolomys clarki.
For both taxa, the sizes and cusp distribution happen
to be much the same. The length range of those available to Sahni ran from 3.15 -
3,6mm, and the cusp formula is 5-6 (labial) : 4 (lingual). For the first mentioned
row, one tooth has the foremost cusp as the smallest, and it's followed by crescentric
cusps with the curve pointing backwards; helpfully directing food towards the entrance
of the reception chute to the recycling department. The lingual brigade are higher
than their colleagues, more proudly erect, and the last but one is the largest. The
occlusal outline of the crown is rectangular. Roots
are widened rectangles in cross section with no accessory assistants.
As for m1s, referrals of m2 are also tentative. One specimen has a cusp formula
4:2, with the labial row reducing down to 3 for later
species of Mesodma. On that row, the first cusp is a cone and its followers
are more backwards pointing crescents. Taking advantage of the available space,
the pair of internal cusps luxuriate by being larger. A ridge runs across the
central valley from the first lingual to the second external cusp, as is typical for
other specimens, and the tooth length averages 2.4mm. The front root is a widened
rectangle.
Upper jaw and premolars
I don't know the origins of the name for Clambank Hollow Quarry, but being a quarry
with a bed of fossil clams in a hollow may have had a role to play. At, least,
there's certainly a clam bed 12 metres to the east, and it's been generous with
other fossils as well. One of these was the sole bit of multi jaw found during three
years of prospecting, and it proudly retained the second and third upper
premolars. It's probably from Mesodma,
based on similarities with material from elsewhere, although it could belong to
Cimexomys judithae.
P2 is a tri-cusped tooth of a somewhat loftier elevation than the following premolars.
A single cusp is labial from the other two. The front
of that pair is taller but thin, whereas the rear one is the larger of the trio.
Double-rooted, 1mm long, 0.7 wide.
P3 seems to be a bit lingually positioned in
comparison to P2, and has one more cusp; ie. two rows of two. The rear couple are
larger but wear was heavy, and many details are obscured. The size isn't much
different to P2: length 1mm, width 0.65, and it also has two roots.
The referral of P4 is put as 'tentative'. As these rear premolars were expected to
partake in some degree of grinding works, the furnishings are more complex than those
provided with their lazier, more forward colleagues. There are three cusp rows
(labial to lingual): 2:6:2. The second cusp of the labial row dominates its front
friend in terms of size. The cusps of the middle row make up a line of cones, the
fifth of which is the highest. As all this stuff requires space, the P4 is a
considerably larger premolar with a length of four millimetres.
Upper molars
A number of M1s were available, with lengths averaging four millimetres and widths
at two (p.370). There are three cusp rows (labial to lingual): 6:7:5. The external
cusps are cones to the front while the rear members show a more pyramid-shaped
tendency. Grooves scar the inner faces. The lingual cusp row gets fed up with life
a bit over the halfway line of the crown and peters out, but none of the five (or
sometimes six) are all that distinct; 'cuspules' wouldn't be an insult. Two features
are probably basal and aren't found in later species.
The numbers of cusps in the labial and middle rows is comparatively modest, whereas
the internal 'cuspules' later became more distinct and clearly separated. The crown
was ably supported by two roots, with the rear one being the widest.
As is to be expected for multis, M2 is a considerably smaller piece of work than its
partner; length 2.1mm, width 1.6. The cusp formula is 1:3:4. The sole
labial cusp sits on a ridge, and the three middle ones
are large and crescentric in shape. The four lingual cusps are well separated (in
contrast to their equivalents on M1), and the front one is joined by a ridge to the
leader of the middle mob.
Sahni notes that this species is suitable as the ancestral form for M. formosa
and M. thompsoni.
Holotype
NMC 1890 is part of a lower jaw in the care of the National Museum of Canada. It was
originally referred to Ptilodus, transferred to a loosely defined
Cimolomys in 1929 and then ushered into Mesodma by Clemens. That
mandible was kindly provided by the Near Steveville
locality, so thanks are due to Near Steve.
Additional notes
Matthew, 1916 (p.479) reports Lambe based the
species P. primaevus on a partial jaw with two teeth from Alberta. One of these was
a premolar.
Several specimens are at the AMNH, New York, where the name M. primaevus is
also used. That's the name Sahni used in 1972. At a guess, I'd imagine the different
ending results from the genders of Latin grammar. |
| References: | Lambe (1902), New genera and species of the Belly River
Series (Mid Cretaceous), p.79 in Osborn & Lambe (1902), Vertebrata of the
Mid-Cretaceous of the North West Territory, Contributions Ca. Pal., 30, Geological Survey
of Canada. |
| Simpson (1929), American Mesozoic Mammalia, Mem. Peabody
Mus. Nat. Hist., 3, pt. 1, xv+171 p. |
| Clemens (1963), Fossil mammals of the type Lance Formation,
Wyoming. Pt. 1. Introduction and Multituberculata, University of California
Publications, Geol. Sci., vol. 48, p.1-105, figs. 1-51. |
| Species: | Mesodma thompsoni Clemens WA, 1964 |
| Aka: | Cimolodon nitidus Marsh, 1889; Cimolomys gracilis (Marsh,
1889) Simpson, 1929; Cimolomys nitidus |
| Place: | Wyoming, Montana, New Mexico, North Dakota, South Dakota, Texas,
Utah? & Alberta, Saskatchewan |
| Country: | USA & Canada |
| Age: | Upper Cretaceous (Campanian - Maastrichtian) - Paleocene (Puercan) |
| Remarks: | The holotype, UCMP 47217, resides at the
University of California. It's a left lower premolar (p4).
This was recovered from Niobrara County, Wyoming. Subsequent finds include a left
dentary with p3 and p4. The latter tooth has 12 serrations
and is lower arched than known from M. formosa, (Hunter & Archibald 2002,
p.194).
The Saskatchewan material probably belongs to a separate species, but it hasn't yet been
renamed. Some further discussion is included in the article on French Fry, below.
A specimen at the Peabody has apparently been assigned to Cimolodon sp. and vice
versa! Weighed approximately 55g. I've seen the year 1963 given for this citation. |
| Reference: | Clemens (1964), Fossil mammals of the type Lance Formation
Wyoming. Part I. Introduction and Multituberculata. University of California Publications
in Geological Sciences, 48, p.1-105. |
| French Fry, after the dinos had their
chips
The following is based upon my reading of Fox, 2002.
One way or another, (or actually in a combination of ways), rocks record information
concerning how and when they were laid down. Much of geology centres upon understanding
such information but, as should be expected, there are complications. The short paper by
Fox gives insights into some, which apply to the Cretaceous-Tertiary transition on land in
North America; the K-T extinction(s) and all that.
As I'm writing this, then mammals self-evidently survived that transition, but discoveries
of remains which are unambiguously very near in time to those event(s) are hard to find,
(p.456). Though 100,000 years is short in terms of geological time, (and is usually of
little significance in Mesozoic research), it equates to about twenty times the length of
written history, 4,000 human generations and many more mouse-sized mammal ones. If you
want strata as close to 65 million years old as possible, things can get frustrating.
Sources of imprecision
In most cases, the relevant mammal fossils were deposited by stream and river action.
While many thousands of specimens have been found, these are generally jaw fragments and
less. Running water is destructive. Another complication is that water doesn't habitually
flow horizontally in thin air. River courses are bedded on, (and cut into), underlying
rock. Often in North America, this also happened to contain fossils. As there was erosion,
transportation and secondary deposit of already fossilized remains, things can be a bit
muddled. Fortunately, characteristic damage generally results from such processes, but
the presence of a few battered Cretaceous scraps in Paleocene sediments can be inconvenient.
Eastern Montana is particularly notorious for this.
A further problem is that it's not always possible to pin-point the K-T border. For example,
in the Ferris Formation
of Wyoming, it's located somewhere with an eight metre zone of uncertainty. Whether it's
high, middle or low in that zone is unclear, thus the uncertainty. The famous iridium
anomaly, informative floral changes, magnostratigraphic markers and radiometric dating all
presently refuse to cooperate there. Elsewhere, such markers may be obliging but
paleoconditions weren't conducive to the preservation of mammals.
I don't want to suggest vertebrate paleontologists aren't grateful for what remains are
available. As they, medical doctors and professional boxers could all tell you, the lower
jaw is the hardest bone in a mammalian body. That's why some of the above derive much
satisfaction from landing a punch bang on it. (Quibbling with a doctor over the details of
the bill can have unpleasant side effects.) Even so, it's amazing that fragments of jaw
can be preserved for tens of millions of years, (and hundreds of millions). Complaining
because it can't be worked out if the specimens are actually 64.99 million years old, rather
than about 64 million, would be showing ingratitude.
A relief road
Nevertheless, sympathetic Canadian road builders have done their best to help out with
unsatisfactory precision. A road called Route 37 provided a convenient cut into the
landscape of southwestern Saskatchewan, twenty miles or so south of the town of Shaunavon,
and this exposed a fossil site called French Fry. This pleasingly well behaved stratum sits
on top of what's known as the Ferris coal seam, which is an approximation of the K-T border
in the region. An unusual feature of this rock is that it's the result of lucristine
deposits rather than fluvial ones. Lake environments are usually less mischievous than the
more disruptive efforts produced by streams and rivers.
The Ferris coal seam is known to mark the K-T border due to a couple of independent
factors, (p.457). Firstly, most plants characteristic of the Cretaceous Woodhouseia
spinata assemblage disappear abruptly. Furthermore, the much cited iridium anomaly is
present at a similar level. The K-T border is located at the foot of the coal. Also
convenient are the side effects of change in the magnetic polarity of the planet. The K-T
transition occurred in the time of reversed polarity 29r. The rock section including French
Fry corresponds in that regard as well. It has a thickness of about thirty metres, and
about two-thirds is Cretaceous. Reversed polarity 29r lasted for about half-a-million
years.
Assuming regular rates of deposition, (which isn't necessarily the case), then each of the
thirty metres would represent approximately 16,700 years. (Information from elsewhere in
Canada suggests that, in appropriate conditions, lake sediments can accumulate considerably
more quickly, with a metre requiring two to three thousand years.) Even allowing for
uneven rates, any fossils originally laid down in the metre of rock above the K-T can
safely be called earliest Paleocene. This is precisely the position of French Fry.
Fauna
It would be nice if we could conclude with a broad list of clearly earliest Paleocene
mammals, as it's clear that the locality is within thousands of years', (not tens or
hundreds of thousands), proximity to the end of the Cretaceous. Presently, there's plenty
of scope for faunal enrichment. As it was a lake, most fossils are from various fish.
These are scales, vertebrae and teeth and are termed
'occasional'. Also known are rare remains of lizards called champosaurs. Mammalia is
presently represented by a well preserved, partial lower jaw of a multi. This is
Mesodma. The p4 premolar corresponds very closely
to remains from the Rav W-1 horizon of Saskatchewan, and these were referred to the species
of M. thompsoni. However, some subtle distinctions suggest this material
collectively represents a different species; perhaps a descendant. Establishing a new
taxon has been deferred until better material is available.
Fox explicitly states: "Therefore, the specimens from Rav W-1 and French Fry cannot
be cited as evidence that M. thompsoni survived into the Paleocene."
A short course in UK English for non-native speakers
'French Fry, after the dinos had their chips.'
French fries are chips, and American potato chips are properly known as crisps. After the
fat lady has sung and you're dead, you've had your chips. They're not just down. It was
finito.
Further Mesozoic site summaries can be found at Localities. |
| Species: | Mesodma hensleighi Lillegraven JA, 1969 |
| Place: | Montana, South Dakota, ?Utah,
Wyoming & Alberta,
Saskatchewan |
| Country: | USA & Canada |
| Age: | Campanian-Maastrichtian, Upper Cretaceous - Puercan, Paleocene |
| Remarks: | Another holotype in the Alberta University. A
furry 15g or about one-and-a-half standard
shrews. South
Dakota is mentioned in Foote et al, 1999.
The Paleocene material is from the
Ferris Formation of Wyoming. It gets a mention in Lillegraven & Eberle, 1999,
(p.702): "That range extension has the effect of increasing Archibald's (1996a)
calculated survival of Lancian species of
multituberculates into the Puercan from 50 percent to 60 percent." |
| Reference: | Lillegraven (1969), Latest Cretaceous mammals of the upper
part of Edmonton Formation of Alberta, Canada, and review of Marsupial-Placental dichotomy
in mammalian evolution. The University of Kansas Paleontological Contributions, 50,
p.1-122. |
| Species: | Mesodma senecta Fox, 1971 |
| Place: | Kalparowits Formation, Utah |
| Country: | USA |
| Age: | Campanian, Upper Cretaceous |
| Remarks: | Holotype at Alberta. Body mass of about two
mice, 50g. |
| Reference: | Fox (1971), Early Campanian multituberculates (Mammalia:
Allotheria) from the Upper Milk River Formation, Alberta. Canadian Journal of Earth
Sciences, 8 (8), p.916-938. |
| Species: | Mesodma garfieldensis Archibald JD, 1982 |
| Place: | Hells Hollow, Montana, Wyoming |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | Probable weight was around 40g. |
| Reference: | Archibald (1982), A study of Mammalia and geology across
the Cretaceous-Tertiary boundary in Garfield County, Montana. University of California
Publications in Geological Sciences, 122, p.1-286. |
| Species: | Mesodma pygmaea Sloan RE, 1987 |
| Place: | Gidley Quarry, Montana,
Wyoming &
Who Nose?, Alberta |
| Country: | USA & Canada |
| Age: | Torrejonian-Tiffanian, Middle Paleocene |
| Remarks: | Very pygmaea indeed, and weighed about 8g.
With regard to specimens, (teeth: -an upper premolar, P4,
and two lower p4s), from an excitingly named new site, Scott, 2003 (p.746) reports:
"The Nose Creek specimens are virtually identical in both qualitative and quantitative
characters to the type material from Gidley Quarry, Fort Union Formation, Montana (Sloan,
1987) and to specimens from Cochrane 2, Paskapoo Formation, Alberta (Youzwyshyn, 1988),
differing only in being slightly smaller and in having fewer serrations on p.4."
These examples, which are housed in the University of Alberta, have nine to ten serrations,
as well as a further incipient one, and provide the earliest evidence of this species in
western Canada.
|
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammals, rates
of sedimentation and evolution, p.165-200 In Fassett JE & Rigby JK (eds.), The
Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado.
Geological Society of America Special Paper, 209. |
| Who Nose?, Calgary -Paleocene
The following is derived from my reading of Scott, 2003.
The Who Nose? locality is considered to be Upper Torrejonian (Paleocene), and is part of
the Paskapoo Formation. It's situated near the Calgary International Airport, and was
discovered in 1989 by Royal Tyrell Museum paleontologist, D Brinkman. Since then, it's
been worked by parties from the University of Alberta.
Calgary boasts a waterway called Nose Creek, which is fed by two branches; West Nose Creek
and North Nose Creek. The mammal locality lies a few hundred metres from the confluence of
them both, on the eastern bank of the west nostril. Quite who came up with the name Who
Nose? isn't explained. As well as the 400 mammalian specimens so far collected, (including
ten or so well-preserved jaws), various fragmentary remains of other critters have also
been recovered. These include fish, amphibians, lizards and crocodiles, (p.745-746).
New multis from the wider Paskapoo Formation
The following is based upon my reading of the text from Scott, 2005. Any page numbers
mentioned are in Roman numerals, and these don't correspond at all with those in the
original publication.
"Neoplagiaulacid multituberculates are among the most numerous and best represented
members of early Cenozoic North American mammal faunas, achieving their greatest diversity
during the Paleocene" (p.i). The Paskapoo Formation seems keen to emphasize this, as
Scott was able to launch four more species; Ectopodus elaphus,
Neoplagiaulax serrator, N. paskapooensis and
N. cimolodontoides. (For clarity, these are not from the Who Nose? locality.) These
are based on some relatively good specimens by North American Paleocene standards, as many
multi taxa saw fit to bequeath little more than isolated
teeth. All the new Albertans kindly included both upper and lower jaw material, and one
(N. cimolodontoides) also agreed to help with information on tooth replacement.
Meet the Formation
Paskapoo is from the Cree language and means 'blind man' (p.ii). I can't see why somewhere
should be named that, so perhaps they were referring to me. The Formation was deposited
along the east of what are now the Rocky Mountains, and outcrops can be found along the
Blindman and Red Deer Rivers of central and southern Alberta. It overlies the Scollard
Formation and must be younger. The main agent involved was river action, and this produced
a considerable number of fossil yielding localities. In terms of North American Land Mammal
Ages, the presence of Plesiadapis rex suggests a middle Tiffanian age (Ti3), which
makes it about contemporary with the Ravenscrag Formation (p.iii).
An intriguing aspect of the mammalian fauna in the Formation, is the wealth of species for
several multituberculates, and all are found at the same stratigraphic level (p.xxvii).
There are perhaps five species of Neoplagiaulax; N. serrator, N.
paskapooensis, N. cimolodontoides and forms comparable with N. hazeni and
N. hunteri. A single locality, Cochrane 2, provides fossils from four members of
Ptilodus and further close relavtives; Baiotomeus and
Prochetodon This is similar to the kind of diversity
achieved by rodents in some modern communities.
It also means the Alberta faunas can be considerable richer than broadly contemporary
locations further south in the US. Whether this reflects the original situation is unclear,
as other factors could be responsible for biases. For example, the ways rocks were
deposited and local conditons, such as water speeds or soil acidity, can have significant
effects on the prospects for preservation.
Further Mesozoic site summaries can be found at Localities.
Meet (some of) the Mammals
As the location is post-Cretaceous, this listing isn't meant to be complete.
Multituberculata
?Acheronodon sp.;
Anconodon cochranensis;
Baiotomeus rhothonion;
Ectypodus ?szalayi;
Mesodma pygmaea;
Mimetodon silberlingi;
Neoplagiaulax hunteri; N. nelsoni;
Parectypodus corystes; P. sylviae;
Ptilodus gnomus; P. montanus;
Stygimys sp.;
Xyronomys sp.
Eutheria
Gelastops sp.;
Procerberus sp. |
| Genus: Mesodmops Tong Y
& Wang T, 1994 |
| Species: | Mesodmops dawsonae Tong Y & Wang T, 1994 |
| Aka: | Mesodmops dawsoni |
| Place: | Wutu Basin, Shandong |
| Country: | China |
| Age: | Lower Eocene |
| Remarks: | The following is based upon my reading of Tong
& Wang, 1994 (particularly pages 282-284). That's an extended, English language summary
provided for dullards, such as me, who are too stupid and lazy to appreciate the joys
and jovialities of Chinese.
In the beginning there was some coal...
...and a small piece of rock. About 10cm² of it. That came from the Wutu Formation, and
it dates from the Lower Eocene (p.282). It turned out to contain bits of the skull from
most likely a single multi. In any event, there's no duplication of body parts involved.
This critter differed from, but was nevertheless rather similar to, North America's
Mesodma. Thus, as presumably explained in the
Chinese text, it was named Mesodmops. Its grave had been in a coal mine near the
village of Wutu in Shandong Province, and it was the first neoplagi multi to be discovered
in Asia.
Mesodmops is a middling-sized member of the family (p.283). While it would
doubtlessly prove to be of interest to a time-travelling cat, the nutritional value of
its luscious body wouldn't suffice to still the appetite of even a kitten; feline-snack
sized.
Toothsomeness
The known dental formula per side is:
Uppers: ? incisors, 0 canine,
4 premolars and 2 molars.
Lowers: 1, 0, 1 and 2 respectively.
Postcanine lengths appear in a table on page 178. Other dimensions are listed as well
including, apparently, deciduous premolars. (The
labelling in the table includes "RdP1" through to "RdP3", "LdP1" and "LdP3".) The English
summary doesn't address those positions. How one mouth might contain so many "milk teeth"
in combination with adult posterior premolars and fully erupted molars, is something I
find strange. However, Missiaen P & Smith T, 2008 tentatively identify a right DP3 for
M. tenuis on the basis of comparisons with M. dawsonae (p.358). Be that as
it may, here are some of the postcanine lengths for M. dawsonae.
Uppers: P4 (2 specimens) 2.60 - 2.70mm; M1 (2 sp.) 2.90 - 3.00mm; M2 (2 sp.) 1.20 - 1.30mm.
Lowers; p4 (1 sp.) 4.30mm; m1 (2 sp.) 2.30 - 2.40mm; m2 (1 sp.) 1.30mm.
All postcanines are narrower than long. All given dimensions may have been rounded. If
that point's mentioned in the text, then it's all Chinese to me.
Concerning the uppers, the P4 has a cusp formula of (buccal
to lingual) 4:7. That's more cusps than is the case for
Mimetodon. The M1 is comparatively large (8:10:5), while
cusp numbers for M2 correspond to neoplagi norms (1:3:3).
The only lower premolar is p4. The ancestors had given up growing any others. It's an
elongated tooth with a low crown bearing 12 serrations. Its length is greater than the
combined total of both lower molars.
The m1 is narrow with a cusp formula of 7:5. The m2 makes do with 4:2. The sole lower
incisor is described as slender.
Affinities
A number of aspects of p4 architecture are typically neoplagi; the lowness of the crown,
its front being higher than the rear, and its great length in comparison to the m1 molar.
These marks of the family. The lowest crowns are sported by Mimetodon,
Mesodma and now Mesodmops (p.284). The degree of
elongation of the p4 and the simpler structure of the M1 are more akin to Mesodma.
However, the first serration of the p4 blade is set higher for Mesodmops, the
length of m1 (compared to that of p4) is shorter, and there's only one lower premolar
left rather than two. The upper M1 is also blessed with less cusps. (That said, the
lower m1 has more cusps than Mesodma thompsoni; 7:5 as opposed to 6:4.)
Food processing by China's Mesodmops presumably placed more emphasis on shearing
with the p4 blade. Mimetodon, in contrast, has more upper molar cusps than the
earlier (in terms of first known appearance) Mesodma.
Go east, young multi
Neoplagis (and, therefore, potential ancestors for this genus) weren't known from the
Cretaceous-Paleocene of Asia. North America is the place for those and, probably, the
original cradle of the family. However, it could perhaps be that the apparent Asian
absence may be misleading. Most Paleocene Chinese mammal fossils available in 1994, the
year of this publication, had come from so called red beds in the south; deposits laid
down in semi-arid, sub-tropical environments. The Wutu formation's coal formed in a
damper climate. Conceivably, neoplagis might have avoided too much aridity like the
plague and, therefore, refused to drop dead and fossilize under such southern regimes.
In any event, the 21st early century fossil record indicates one neoplagi lineage, closely
related to Mesodma, packed its cases and left North America in search of a new
home on the humid range of (at the latest) Eocene China. The authors briefly speculate
on Paleocene origins for their new genus. The subsequent publication of a second species
in 2008, M. tenuis, provides support for that supposition. It hails from the
Upper Paleocene of Inner Mongolia, northern China. Its authors point to possibly
transitional states of that species intermediary between Mesodma and
Mesodmops dawsonae (eg. the m1 cusp formula).
Holotype
IVPP V10699 is a partial skull and lower jaws now living at the Institute of Vertebrate
Paleontology and Paleoanthropology, Beijing.
The specific name gets incorrectly spelt at several stages of Tong & Wang (eg. p.277
and 283). It morphs into 'dawsoni'. Presumably, the Dawson being honoured is M Dawson of
the Carnegie Museum, Pittsburgh. He's the only one I could find mentioned in the study.
|
| Reference: | Tong & Wang (1994), A new neoplagiaulacid multituberculate
(Mammalia) from the lower Eocene of Wutu Basin, Shandong, Vertebrata PalAsiatica, 32,
p.275-284. (Chinese with summary in English.) |
| Species: | Mesodmops tenuis Missiaen P & Smith T, 2008 |
| Place: | Subeng, Inner Mongolia |
| Country: | China |
| Age: | Upper Paleocene |
| Remarks: | The following is based upon my reading of
Missiaen & Smith, 2008.
Subeng, in Inner Mongolia, has a fossil locality dating from the Upper Paleocene (p.357).
It's close in age to the long known mammal fossil fauna from Gashatan. Research at Subeng
first got underway with the site's discovery in 1976, but the fossils collected by that
and subsequent expeditions had to be patient before being properly studied. Its mammals
were the objectives of this paper. While the authors attended to the needs of a menagerie
of placentals, I'm restricting my interest on the fewer
multituberculates. Seventeen species were
identified in all including three multis. All the multi genera had previously been met
at other localities, but one of the species, this one, was new.
As well as being a geographical term, the word also has a second job of being an ALMA (an
Asian Land Mammal Age). That's a stretch of fossilized local history defined in terms of
the first appearance of a particular index taxon, and it
happens to have preceded the Burbanian ALMA. Gashatan aged localities include Gashato,
Zhigden, Naian, Khaychin-Ula (all in Mongolia) and China's Nomogen, Bayan Ulan and now
Subeng.
The new star
Remains assigned to the new species are restricted to isolated teeth, but they used to be
parts of bodies. The sizes of molars are similar to those
from M. dawsonae, but they're proportionately narrower, and the cusp formulae of lowers
differ (p.358). The upper M1 has small front cusps, and those of the middle row are squarer
as opposed to more rectangular. Specimens are available from five dental positions; all
the molars and a probable deciduous premolar.
Lengths
In each case, the length of only a single specimen is presently known.
Uppers: P3? 0.73mm; M1 3.28mm; M2 1.30mm.
Lowers: m1 2.15mm; m2 1.20mm.
Upper molars
M1 has a cusp formula of 8:10:5 (buccal to
lingual. The cusps increase somewhat in size from front
to back. Those in the middle row start as small pyramids and then expand into larger
crescents. M2 has a formula of 1:3:3.
Lower molars
The m1 has a rectangular outline with its sides running roughly in parallel. There are
two cusp rows; 6:5. Cusps have grooves on their internal sides, and the first of each
row is significantly small. The shape of cusps varies from front to rear from sub-pyramidal
to increasingly crescentric. On m2, in contrast, the cusps become somewhat less crescentric
along the series; formula 3:2.
Milk tooth?
One specimen, based on comparisons with M. dawsonae, may be a right (deciduous) DP3.
Its formula of 2:3 is the same as for that species, and the shape is also similar. However,
this specimen is smaller and proportionately narrower.
Comparatively speaking...
Lower molars of the new species are less rounded and the sides are less smooth (p.359).
For m1, Mesodmops dawsonae has curved rows of cusps that veer away from the middle
of the crown at the front and back towards it at the rear. Both lower molars have less cups
for the new species (m1 6:5 rather than 7:5; m2 3:2 rather than 4:2). Other distinctions
are found in the upper first molar. The size differential between front cusps (smaller)
and rear cusps is more pronounced, and the middle row cusps are more square than
rectangular.
The presence of this genus in the Paleocene of China was thought probable, and is now
confirmed. This was because the Eocene Mesodmops shares strong similarities with
the earlier North American Mesodma and, should these have
been matters arising from common descent, then there must've been intervening descendants /
ancestors both in terms of geography and chronology. The new species indicates there
were. Unfortunately, final premolars haven't yet been
discovered for M. tenuis. That's a drawback as those teeth happen to be the most
informative means presently available for identifying the systematics of
neoplagiaulacid multis. The cusp formula of m1 for the new species does happen to be
intermediate between Mesodma thompsoni (6:4) and Mesodmops dawsonae, and the
m2 formula matches that of the American cousin.
Holotype
The type fossil, IMM-2004-SB-013, is a lower molar kept at the Inner Mongolian Museum.
The specific name comes from the Latin tenuis, meaning thin, slender and that
sort of thing. The molars are comparatively slender in contrast to the other known
species. |
| Reference: | Missiaen & Smith (2008), The Gashatan (late Paleocene)
mammal fauna from Subeng, Inner Mongolia, China, Acta Palaeontologica Polonica, 53(3),
p.358-378. |
| Genus: Mimetodon Jepsen GL,
1940
Aka : Ectypodus (partly); Mesodma (partly); Neoplagiaulax(partly)
Remarks: McKenna & Bell (1997) again lists material from the Upper Paleocene? of
Europe.
| Reassigned species: M. douglassi Jepsen, 1940 see
Baiotomeus douglassi; M. trouesseartianus
Jepsen, 1940 see Parectypodus trouvessartianus | |
| Species: | Mimetodon churchilli Jepsen GL, 1940 |
| Place: | Princeton Quarry, Wyoming |
| Country: | USA |
| Age: | Tiffanian, Middle Paleocene |
| Remarks: | Another Peabody collection holotype. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Pro. Amer. Philos. Soc, 83, p.217-340. |
| Species: | Mimetodon silberlingi (Simpson GG, 1935) Schiebout,
1974 |
| Aka: | Ectypodus? silberlingi Simpson, 1935; Mesodma silberlingi
Van Valen & Sloan, 1966; ?M. nanophus |
| Place: | Gidley Quarry, Montana & Wyoming & N Dakota & Alberta |
| Country: | USA & Canada |
| Age: | Torrejonian-Tiffanian, Middle Paleocene |
| Remarks: |
The Yale VP catalogue includes E.? silberlingi as well as M. silberlingi.
Weighed about 20g.
Scott, 2003 (p.747), reports on some fossils from a Calgary site called
Who Nose?, which are the earliest traces of this species
in western Canada. These consist of two upper premolars,
three upper molars and three lower premolars, (P4s, M1s and
p4s). As is typically the case for cimolodontan
multis, these p4s are relatively large shearing teeth. In this instance, their crowns
possess 10-11 serrations. They can be admired in the University of Alberta
Multituberculata Sanctuary. |
| Reference: | Simpson (1935), New Paleocene mammals from the Fort Union of
Montana. Proc. US Nation. Museum 83, p.221-244. |
| Species: | ?Mimetodon nanophus (Holtzman, 1978) |
| Aka: | Neoplagiaulax nanophus Holtzman, 1978 |
| Place: | Tongue River Formation, North Dakota |
| Country: | USA |
| Age: | Middle-Upper Paleocene |
| Remarks: | Scott, 2005 treats this as a species of
Neoplagiaulax. It's poorly known and, if Scott's
iterpretation is correct, then both the upper and lower fourth
premolars have unusually low crowns with steep front
margins. These characteristics are also applicable for N. serrator (p.xii). This
species may also be present at the Diss locality of ALberta.
Might be the same as M. silberlingi. |
| Reference: | Holtzman (1978), 1978. Late Paleocene mammals of the Tongue
River Formation, western North Dakota. Report of Investigation, North Dakota Geological
Survey, 65, p.1-88. |
| Species: | Mimetodon krausei Sloan RE, 1981 |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | Another Peabody collection holotype. |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates from
the San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan Basin
paleontology. University of New Mexico Press, Alberquerque. |
| Genus: Neoliotomus Jepsen
GL, 1930
'new Liotomus'
Aka : Eucosmodon (partly)
Remarks: This genus is not within Neoplagiaulacidae. It's considered to be a
ptilodontid-like critter of unclear affinities. |
| Species: | Neoliotomus conventus Jepsen GL, 1930 |
| Place: | Wyoming & Fort Union Formation, Montana & Colorado |
| Country: | USA |
| Age: | Clarkforkian, Paleocene |
| Remarks: | A mighty multituberculate of around 1,9kg. The
holotype is in the Peabody collection. |
| Reference: | Stratigraphy and paleontology of the Paleocene of northeastern
Park County, Wyoming. Proceedings of the American Philosophical Society, 83 (2), p.463-528. |
| Species: | Neoliotomus ultimus (Granger W & Simpson GG, 1928)
|
| Aka: | Eucosmodon ultimus Granger WD & Simpson GG, 1928 |
| Place: | Wyoming & Colorado |
| Country: | USA |
| Age: | Wasatchian, Eocene |
| Remarks: | Slight timekeeping uncertainty
According to the authors, the original material for Eucosmodon ultimus came from the
Wasatch Formation of Wyoming, which overlies the Clark Fork horizon. I've seen this
species referred to somewhere as Clarkforkian, which correlates to late in the Paleocene.
The Wasatchian is mainly lower Eocene, and John Alroy's database gives a timespan of 55 Ma
to 54 Ma for the species. It also indicates that McKenna was the first to reassign the
critter to Neoliotomus in 1960. As the following entry is based mainly on Granger
& Simpson, 1928, I'll be using the older generic name.
Funeral for a Friend
Until 1880 the fossil record of multituberculates was considered to range from the Triassic
to the Jurassic. However, the earlier material was provided by
'haramiyidans', and nobody presently regards then as multis, although there is a view
that at least some may be related. Lemoine then announced the discovery of certain multi
fossils from Paleocene rock in France. These were closely followed by Cretaceous and
Paleocene discoveries from North America. Sadly, that appeared to be the end of this
heroic line. Much mourned by their admirers, these charming animals were consigned to
extinction during the close of the Paleocene. So it goes.
Hello Yellowbrick Road
At least one expert thought the funeral announcement was a bit hasty. This was
Professor Eucosmodon, who claimed to have been actively breeding in an Eocene bed.
Those antics were briefly reported in 1914 but, perhaps distracted by an outbreak of
collective crass insanity in Europe - The War to End All Wars Part One - CNN and the internet
failed to enthuse with the news. Slightly slighted, Professor Eucosmodon went
back to the Eocene bed for some more breeding.
The first of the 'last' multis
One or two liberties have crept into the above text, so I think I'll briefly straighten the
story out. Granger found the first specimen in 1912, and Stein collected three more the
following year. All were obtained from the Sand Coulee beds, and found in association with
typically Eocene placentals. Granger included a brief
mention of their existence in a 1914 paper. As they were found (from G & S, 1928):
"at different localities in different years and by different collectors...", there
was no room left for reasonable scepticism concerning the provenance (p.1).
That pair of authors assigned these remains to the already established genus of
Eucosmodon. (Reminder: McKenna transferred them
in 1960.) If the animals had been alive and kicking, then generic differences might have
been obvious enough. However, none were apparent in 1928 (p.2). Two species were probably
involved, but one of them deigned to deliver nothing more than an
incisor, and thus provided no basis for a specific
definition.
Dental dimensions
The star fossil described was a piece of lower jaw with two teeth; the p4
premolar and the first molar.
This p4 has a length of 11.4 millimetres and is equipped with 14 serrations. Its companion
is 7.3mm long, has a maximum width of 3.7mm and two rows of cusps. Six are on the
buccal side with four on the
lingual.
Two of the other specimens were isolated incisors, and
these broadly conformed to expectations for Eucosmodon. One is both
larger and more compressed than the other, so they probably don't represent the same
species. The second is 6.1mm long, as opposed to 7.3, and closely matches the size then
known from E. americanus. The restricted band of enamel was wider. Which (if either)
belong to E. ultimus couldn't be ascertained.
Holotype
The holotype, AMNH 16103, is a fragment of dentary now
resident in New York. The origin of the specific name isn't revealed, but it's presumably a reference to
the late occurrence of this multi.
Additional notes
Specimens in the AMNH, New York, the Peabody and Wyoming. Known
from a fair number of locations. Another large multi, which weighed perhaps 2 kilos. |
| Reference: | Granger & Simpson (1928), Multituberculates in the
Wasatch Formation, American Museum Novitates, 312, p.1-4. |
| Genus: Neoplagiaulax
Lemoine V, 1882
'new Plagiaulax'
Aka: Ectypodus? (partly); Plagiaulax (partly); Ptilodus (partly)
Remarks: A nomenclatural minefield. Some material has also been reassigned to
Eucosmodon.
2006, New from Montana
According to Bloch J, Boyer D & Krause D (Society of Vertebrate Paleontology Abstracts, 2006,
p.43A9, this genus also occurs at Donald Quarry (Upper Paleocene), Montana. It's
one of at least three multis accused of having lived there during the Tiffanian, by
researchers from the Florida Museum of Natural History and Stony Brook University.
The mammalian fauna reportedly so far includes 30 species. Its named multi mates
are Ptilodus and
Anconodon.
Reference: Lemoine (1882), Sur deux Plagiaulax tertiaires, recueillis aux environs de Reims.
Comptes Rendus de l'Academie des Sciences, Paris, 95, p.1009-1011.
| Reassigned species: N. americanus Cope, 1885 see
Eucosmodon americanus and
Eucosmodon primus; N. douglassi
Schiebout, 1974 see Baiotomeus douglassi;
N. fractus Dorr, 1952 see Ptilodus fractus;
N. molestus Cope, 1886 see Eucosmodon
molestus; N. nanophus Holtzman, 1978 see
?Mimetodon nanophus; N. trouessarti see
Parectypodus trovessartianus | |
| Species: | Neoplagiaulax eocaenus (Lemoine V, 1880) Lemoine,
1882 |
| Aka: | N. eocänus, Plagiaulax eocaenus |
| Place: | Cernay |
| Country: | France |
| Age: | Upper Paleocene |
| Remarks: | According to Scott, 2005 (p.xi not the orginal
page number), both the upper and lower fourth premolars
display an unusually wide range of variation. This suggests the possibility that a larger
number of taxa may be bundled together with this species.
Euro Neoplagiaulax
None of the North American cousins seem to show signs of particularly close affinities with
the European branch of the genus (p.xxviii). The American N. serrator,
N. paskapooensis, N. hazeni and N. hazeni all have similarities in the
p4 lower premolar with the Europeans N. eocanus and N. copei. However, they're
generally more like their North American colleagues. The similarities seem to be matters
of convergence. Whether the taxon is a genuine genus is also in doubt. It could be a
looser association of neoplagiaulacids belonging to more than one, rather similar generic
lineage.
Additional notes
Descendant of N. hazeni, (Burkitt JH), but this seems unlikely. A specimen is in the
Peabody, Yale. |
| References: | Lemoine (1880), Communication sur les Ossements fossiles des
terrains tertiaires inférieurs. Association Française pour l'Avancement des Sciences,
Reims, p. 3-40. |
| Lemoine (1882), Sur deux Plagiaulax tertiaires, recueillis aux
environs de Reims. Comptes Rendus de l'Academie des Sciences, Paris, 95, 1009-1011. |
| Species: | Neoplagiaulax copei Lemoine V, 1885 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | Descendant of N. hazeni, (Burkitt JH).
Specimens at the AMNH, New York. |
| Reference: | Lemoine (1885), Étude sur quelqes mammifères de petite taille de
la faune cernaysienne des environs de Reims. Bull. Soc. Géol. France 3, p.203-217, pls.
x-xii. |
| Species: | Neoplagiaulax grangeri (Simpson GG, 1935) Gazin,
1969 |
| Aka: | Ectypodus? grangeri Simpson, 1935d |
| Place: | Gidley Quarry, Montana |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | Descendant of N. hazeni, (Burkitt JH).
Weight of around a quarter of a standard rat, 100g. |
| Reference: | Simpson (1935), New Paleocene mammals from the Fort Union of
Montana. Proc. US Nation. Museum 83, p.221-244. |
| Species: | Neoplagiaulax hazeni (Jepsen GL, 1940) Krause DW,
1977 |
| Aka: | Ectypodus hazeni Jepsen GL, 1940; N. fractus
(partially) |
| Place: | Princeton Quarry, Wyoming & North Dakota |
| Country: | USA |
| Age: | Tiffanian, Middle-Upper Paleocene |
| Remarks: | Further material, including the type fossil, can
be visited at Yale. Body weight estimated at 95g. |
| References: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Proceedings of the American Philosophical Society, 83 (2), p.217-338. |
| Krause (1977), Paleocene multituberculates (Mammalia) of the Roche
Percee Local Fauna, Ravenscrag Formation, Saskatchewan, Canada. Palaeontographica Abteilung
A 159, p.1-36. |
| Species: | Neoplagiaulax hunteri (Simpson GG, 1936) Krause DW,
1977 |
| Aka: | Ectypodus hunteri Simpson, 1936c |
| Place: | Alberta and Scarritt Quarry, Montana & Wyoming & North
Dakota |
| Country: | Canada & USA |
| Age: | Torrejonian-Tiffanian, Middle Paleocene |
| Remarks: | Several specimens are at the Peabody, Yale, where
the name E. is sometimes employed. Weighed about 45g.
Several specimens have recently been identified from the
Who Nose? fauna of Calgary, Alberta, (Scott 2003, p.750). |
| References: | Simpson (1936), Census of Paleocene mammals. American Museum Novitates
848, p.1-15. |
| Krause (1977), Paleocene multituberculates (Mammalia) of the Roche
Percee Local Fauna, Ravenscrag Formation, Saskatchewan, Canada. Palaeontographica Abteilung
A 159, p.1-36. |
| Species: | Neoplagiaulax macintyrei Sloan RE, 1981 |
| Place: | San Juan Basin, New Mexico & Utah |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates from the
San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan Basin
paleontology. University of New Mexico Press, Alberquerque. |
| Species: | ?Neoplagiaulax burgessi Archibald JD, 1982 |
| Place: | Hell Creek, Montana |
| Country: | USA |
| Age: | Maastrichtian, Upper Cretaceous |
| Remarks: | This species is an early representatvie. |
| Reference: | Archibald (1982), A study of Mammalia and Geology across the
Cretaceous-Tertiary Boundary in Garfield County, Montana. University of California
Publications in Geological Sciences, volume 122, p.242-243. |
| Multituberculate Hunting and Fossil Biases
The following is derived from my reading of Fox, 1968, (see Bibliography).
Fox's paper concerns the diversity of the then known
multituberculate genera in North America during the Upper Cretaceous - Paleocene. Much
more material has since been discovered, but his observations still offer relevant insights
regarding limitations of the known fossil record, at whatever stage of research. It was
written in response to a view that generic diversity of multis increased during the
Campanian and Maastrichtian. Fox found this uncertain, (p.339).
First find your fossils
There are two standard methods of prospecting for small fossils. One involves crawling
around on your hands and knees, and staring at the ground. I've done this when looking for
remains of belemnites. It works but it's a great way of confusing the eyes, deadening the
fingertips and numbing the mind. You also don't recover anything from just below the
surface. The second method involves processing rock or sand through sieves and screens.
This sorts the material by size, which makes the recognition of fossil remains easier.
Screening also increases the scope of the sample. This isn't a replacement for crawling
around. That may help decide where to sieve.
Screening techniques have substantially increased both the number and variety of mammal
remains available. However, they can only help reveal what's there to be found. Inherent
biases of the fossil record still remain unaffected, and require consideration.
RIP
The relevant sites are generally death assemblages. Remains were brought together post
mortem by some mechanism or other; often river action. Consequently, it can't be reasonably
assumed that the fossils are necessarily a typical representation of the paleo-fauna. In
life there might have been more diversity. Processes of fossilization may have favoured
preservation of particular faunal sections. Human choice and chance are involved in exactly
which locations are sampled, and inferences are made on account of the available evidence.
All these factors can introduce biases.
This means that conclusions concerning an increase in the proportionate number of
multituberculates within the total mammalian fauna could be less secure than they may
appear, (p.340): "... the "total mammal fauna" of this interval has never
been known, is not known, and never shall be known." (This refers specifically to the
Lance and Bug Creek strata, but it equally applies to other localities.)
Insufficient sampling could also be a source of bias. If a location continues to yield new
taxa, then it would be premature to assume, that the broad
picture is sufficiently known. Plenty of new taxa have been described since this paper was
published, (1968), and there's nothing to indicate that the supply is running dry. This is
in part, but not only, due to new localities.
The plains
Generally, the Upper Cretaceous strata in North America which yield multis are ancient
floodplains, which then bordered the mid-continental sea. This environment would have been
divided into smaller habitat zones, as dictated by the presence of rivers, streams, lakes
and swamps (p.341), (and presumably further factors). Higher lands existed further to the
west, and conditions must've differed to those of the floodplains. This suggests the
inhabitants also differed. As upland conditions weren't favourable for fossilization, that
fauna is largely unknowable. Concerning dinosaurs, the relative paucity of juvenile remains
in many locations cannot reflect a genuine shortage of young dinos. (That's how all the
adults started out.) It must indicate a bias, which may well be the result of different
habitats at differing stages of life. "There is no a priori reason why mammals of
diverse kinds could not have been similarly distributed."
Missing multis
Fox refers to four multituberculate genera which then were, and still are, unknown from
deposits earlier than the Lower Paleocene: Eucosmodon, Ptilodus,
Neoplagiaulax and Parectypodus. "Only the paleontologically deficient
would suppose that those sprang fresh from the brow of Jove at the time of the demise of
the dinosaurs." Each of these genera was probably established somewhat earlier than
the age of the oldest finds, and the Upper Cretaceous isn't unlikely. In all cases,
there's a chance that they first arose in the blank spaces of the fossil record, (which are
most of it). Whilst there may have been an increase in North American multi diversification
during the Upper Cretaceous, this could also be an artefact resulting from biases of
preservation and sampling. |
| Species: | Neoplagiaulax kremnus Johnston PA & Fox RC,
1984 |
| Place: | Rav W-1, Saskatchewan & Montana |
| Country: | Canada & USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | Holotype at Alberta. |
| Reference: | Johnston & Fox (1984), Paleocene and Late Cretaceous mammals
from Saskatchewan, Canada. Paleontogr. Abt. A: Paläozool., Stratigr. 186, p.163-222.
|
| Species: | Neoplagiaulax annae Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Neoplagiaulax nicolai Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Neoplagiaulax sylvani Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Neoplagiaulax jepi Sloan RE, 1987 |
| Place: | Cedar Point Quarry and
The Breaks, Wyoming |
| Country: | USA |
| Age: | Tiffanian, Paleocene |
| Remarks: | |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammal ages,
biozones, magnetozones, rates of sedimentation, and evolution, in Fassett JE &
Rigby JK (eds.), The Cretaceous-Tertiary boundary in the San Juan and Raton Basins, New
Mexico and Colorado, Geological Society of America Special Paper 209, p.165-200. |
| Species: | Neoplagiaulax macrotomeus (Wilson, 1956) Sloan,
1987 |
| Aka: | Ectypodus macrotomeus Wilson, 1956 |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan-Torrejonian, Lower Paleocene |
| Remarks: | Derived from Mesodma formosa, (Burkitt
JH). Weighed in at about 15g. |
| Reference: | |
| Species: | Neoplagiaulax mckennai Sloan RE, 1987 |
| Aka: | N. mckennaiai |
| Place: | Love Quarry, Wyoming & North Dakota |
| Country: | USA |
| Age: | Tiffanian, Middle-Upper Paleocene |
| Remarks: | Weight guestimate, 60g. |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammal ages,
biozones, magnetozones, rates of sedimentation, and evolution, in Fassett JE &
Rigby JK (eds.), The Cretaceous-Tertiary boundary in the San Juan and Raton Basins, New
Mexico and Colorado, Geological Society of America Special Paper 209, p.165-200. |
| Species: | Neoplagiaulax nelsoni Sloan RE, 1987 |
| Place: | Wyoming & Purgatory Hill, Montana & Alberta |
| Country: | USA & Canada |
| Age: | Puercan- lower Tiffanian, Paleocene |
| Remarks: |
The type fossil is from Keefer Hill, (aka Shotgun), Wyoming. At
least one specimen is at Yale. A mouse-sized 25g.
An upper premolar (P4) has recently been identified in the
Who Nose? fauna of Alberta, (Scott 2003, p.750). If
correctly diagnosed, this shows that N. nelsoni and N. hunteri coexisted. It
has previously been suggested that this species was ancestral to the second named one,
partly because it was geologically older. |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammals, rates
of sedimentation and evolution, p.165-200 In Fassett JE & Rigby JK (eds.), The
Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado.
Geological Society of America Special Paper, 209. |
| Species: | Neoplagiaulax serrator Scott CS, 2005 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
Remains or this species are relatively extensive for a neoplagi. Finding upper and lower
jaws in association is unusual for these critters, yet the Paskapoo Formation managed to
provide such a specimen. It was a middling-sized member of the genus. In terms of lower
premolar length (p4), N. serrator is 25% larger
than N. macintyrei and N. nanophus (see Mimetodon
nanophus), but 25% smaller than N. mckennai and N. grangeri (p.vii).
This tooth has more serrations than for any other species. It appears to be most similar
to N. hunteri, N. kremnus and N. eocaenus. However, both lower p4 and
upper P4 have lower crowns, and are nevertheless steeper at the front. A further contrast
to the last mentioned species is the retained p3.
Upper premolars
The first upper approaches an oval shape when viewed from the
occlusal perspective, and has two cusps on the labial
side and a singleton to the rear on the lingual portion.
P2 is double-rooted and roughly circular (p. viii). A large, labial cusp dominates and
two smaller ones are to the lingual. P3 has a lower crown. It's also got two roots but
the outline of the crown is more rectangular. A pair of cusps is found on both sides.
Upper multi P4s were more complex teeth, as they were involved in cutting food rather than
simply keeping hold of the stuff. Cusp numbers are variable. Up to two are on the labial
side (usually one but sometimes none), ten are generally arrayed along the middle (counts of
nine and eleven also occur), and the lingual portion of the crown is a cusp-free zone. The
tooth is wider at the front than the rear, and also low in height. The cusps of the middle
row increase in size along the series until the final two or three. These premolars are
most similar to counterparts from N. hunteri but they're shorter, narrower and
lower.
Upper molars
The molars also have most similarity with N. hunteri, but they're shorter and the
M1s don't have as many cusps. The most popular form is 7:12:6 (
buccal to lingual). The lingual row is the most
variable in number (5-8), and commences alongside the third to sixth cusp of the middle row.
The M2 is a smaller tooth with only two cusp rows (3-4:4).
Lower jaw
The dentary doesn't differ much from other Neoplagiaulax
species or known ptilodontoids for that matter. The main branches of the bone are deep, and
this applies particularly for the area beneath the
postcanines (p. ix). There's a strong coronoid process beginning internally from
alongside of the first lower molar. The top of this process is damaged, but it reached a
height superior to that of the p4 crown. The dentary condyle (the lower part of the jaw-skull
joint) is large and wide. Each specimen has at least two mental foramina beneath the
tooth row.
Lower incisor
As typical for multis there was only one per jaw half. This was a long, elegant tooth
flattened on the internal side.
Lower premolars
Also typical of cimolodontan multis is the pathetic p3.
Some more derived neoplagis were so unimpressed with this
inheritance, that they dispensed with the tooth entirely.
The p4 was the only real chopping tooth on the dentary, and its crown is relatively long and
low judged against Neoplagiaulax norms. The front of the blade rises steeply and is
mildly convex while the rear slope descends more gently. Plentiful serrations occur along
the way. There are between sixteen to nineteen of them, with seventeen being the most
popular number. The foremost ones are rather fine, but the serrations become larger along
the line. The blade reaches its highest point between the sixth and tenth serrations, and
this seems to be characteristic for the genus.
Both sides of the blade are flat excepting for ridges associated with the serrations, although
not in the case of the final three or four. Often, there's a large, round wear facet
towards the rear on the labial face (p. x).
Lower molars
Most commonly, the m1 has a cusp formula of 10:5 (buccal-lingual),
though only four cusps for the internal row also occurs. Crowns are close to rectangular
in outline, and the rows drift further apart from one another towards the rear. For the
buccal row, the cusps vary from being near to pyramids (front) to crescents (rear). They
also become increasingly tall to the fifth or sixth, and then remain about the same height.
An exception can occur in the form of a larger final cusp.
The lingual cusps have flat 'internal' faces and convex
lingual ones. I suppose 'internal' here refers to buccal and the perspective is from the
centre of the crown. The foremost cusp is a bit of a dwarf but the rest are both bigger
and higher. The final member is the biggest, and can be up to twice the length of its front
neighbour. These m1s aren't much different from those of N. hunteri. However,
they're smaller and typically possess one fewer lingual cusp. The buccal faces for both rows
of cusps carry strong grooves caused by wear. The lingual surfaces of some lingual cusps
have weaker grooving.
The cusp formula of the m2 is more variable. This could perhaps partly be due to the larger
number of specimens, as the second molar wins by 22-15. Most popular is 5:2 but the range
is 4-6:2-3. The crown is approaching a trapezoid in outline. Buccal cusps are crescent-shaped
while the lingual ones are larger. Of those, the first is a crescent with the second being
more like a pyramid. In contrast to the m1, the grooving effects are strongest on the
lingual faces. This difference is caused by the relative positions of the molars, as they
weren't aligned straightly.
Affinities
N. serrator appears most closely related with N. hunteri and N. kremnus.
However, the lowness of the crowns of the fourth premolars, both upper and lower, and the
low placement of the first serration (p4) seem to be comparatively primitive traits (p.xii).
The large number of serrations is a peculiarity of the species.
Holotype
The type fossil, UAL VP 46025, is a partial skull with lower
mandible in the collection of the University of Alberta, Edmonton. The specific name
is Latin for 'sawyer', and this refers to the plentitude of serrations on the lower p4
rather than any Twain-esque literary ambitions. |
| Reference: | Scott (2005), New neoplagiaulacid multituberculates (Mammalia,
Allotheria) from the Paleocene of Alberta, Canada, Journal of Paleontology, 79(6),
p.1189-1213. |
| Species: | Neoplagiaulax paskapooensis Scott CS, 2005 |
| Aka: | N. hunteri (partly) |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
This is a relatively large species (p.xii). In terms of the length of the p4
premolar, it beats N. macintyrei and N.
nanophus (see Mimetodon nanophus) by 35%. Nevertheless,
it's around 10% shorter than N. mckennai and N. grangeri. This tooth is also
relatively long in comparison to its height, which also means the crown's low. A contrast
to N. serrator is the gentler slope of the front margin. The closest similarities
are with N. hunteri and N. copei.
Exceptionally for a neoplagi, the upper dental series of the holotype is complete, and only
the left m2 is absent from the lower jaws. Such a complete set hadn't previously been
reported.
Upper incisors
There are two per side, I2 and I3. The ancestors got rid of I1 earlier. I2 is a long
tooth, but the crown only accounts for a third of it (p.xiii). The root is elliptical in
cross-section, and this is consistent with permanent rather than
deciduous incisors. Both I2s run roughly parallel with each other. They're not closely
packed together as known from microcosmodontids
and djadochtatherioids. The I3 is a broader, shorter and chunkier
incisor (p.xiv). A lack of discernable wear facets suggests this tooth didn't directly
occlude with the lower one.
Upper premolars
The expected number would be four per side and that's how many are present. Apart from
being a bit larger, the first three are much like the corresponding teeth of N. serrator
and N. hunteri. P2 deviates to some extent, as the
lingual cusp row is composed of a duo rather instead of a soloist.
P4 most closely resembles N. hazeni, but it's both lower crowned and smaller. The
most common cusp formula is given as (0)4:8:0 (labial to
lingual). Seen from the side, the tooth has a fairly straight front slope with a steeper,
somewhat concave descent to the rear. A cusp is sometimes present low down at the back of
the crown, while a labial lobe is always found at the front, and it houses from two to four
cusps.
Upper molars
The most common cusp formula for the first molar is 7:10:4 but variation on that occurs in
all rows. The buccal cusps are similar to one another in
height with the exception of the smaller first one. The middle row cusps are larger. Most
are quadrate in outline, but there's a tendency towards a slightly crescent shape further
back along the line. The lingual row is shorter, as it ends next to the fifth of sixth
middle cusp. Strong grooving isn't apparent on the faces of the middle cusps, and this is
in contrast to the situation found with N. hazeni (p.xv).
Second molars have two cusp rows; 3:3. Rather than a buccal row, the cusps have been
amalgamated into a long ridge. The middle row commences with a small, low cusp which is
followed by two larger companions. Lingual cusps are
smaller and lower than the middle ones, and they diminish along the line from front to
back. The only discernable wear consists of light grooves on the lingual faces of the
lingual cusps.
Lower jaw
What's known of the dentary is in broadly in line with other
neoplagis, but there are some differences of detail. For example, the dentary condyle is
set at a lower level than for N. serrator, and the area for articulation with the
skull joint is more elongated and has a greater area.
Lower incisor
As was the multi wont there was only one per side. It's a stronger and longer tooth than
found in N. serrator; closer to N. hazeni. The incisor lies procumbently
and curves in towards the middle to some degree. Wear on the upper surface was mostly
caused by the I2.
Lower premolars
The p3 is a small piece of junk, which tried to hide its inadequate physique by taking
refuge in a concavity on the front of the only functional premolar.
The p4 is largely a blade with (usually) 14 serrations. In some cases there's one less
(p.xvi). From the occlusal perspective, the outline of
the crown approaches a trapezoid in shape. At the front, the blade ascends more gently
than is the case for N. serrator. The first serration is located higher up than is
usual for the genus, at a position about one sixth along the length of the tooth. The crown
climaxes in height at the fourth or fifth serration, and then descends. Serrations on the
downwards journey are closer to each other and rougher. The sides of the blade are adorned
with ridges which begin at the serrations, excepting for the final three or four.
Lower molars
The most fashionable cusp formula for the m1 (buccal to
lingual) us 7:4, but there's sometimes a fifth cusp for the
internal row. The outline of the tooth is roughly rectangular, and there's only a narrow
valley between the cusp rows. Buccal cusps are robust. Those to the front are four sided
whereas the rear two or three are somewhat crescentric. There's an increase in dimensions from
the first to the fourth or fifth, with the rest being similarly sized. Lingual cusps are
also robust but higher. With the exception of the smaller leading one, these cusps are
close to one another in size. Wear has left a measure of grooving on the buccal faces.
This molar is reminiscent of N. hazeni but it's smaller, has less cusps and the
buccal ones are less crescent-shaped.
The m2 cusp formula is 4:2. Buccal cusps don't differ much in size and are somewhat more
crescentric than their m1 counterparts. Lingual cusps are bigger, and grooving is sometimes
evident on the lingual face. The first is crescent-shaped while its follower is more
triangular. Given the similarities evident from other teeth, this is unsurprisingly also
most like the corresponding tooth of N. hazeni.
Neoplagi puzzles
N. paskapooensis resembles N. hazeni, but some distinctions are mentioned
above. The lower p4 also has features in common with N. copei from France.
However, the average length is less (4.85mm against 5.51), the crown is proportionately
lower and there are less serrations (p.xvii).
In the case of the holotype, the dentition was found as an
almost complete set. Had they been isolated, then there's a strong chance some may well
have been referred to N. hazeni. This serves to emphasize the diagnostic importance
of the lower p4 premolar, as that's where significant distinctions are at their most
concentrated and helpful (p.xviii).
Holotype
The type fossil, UAL VP 46138, is a partial skull with remains of associated lower jaws.
The specific name refers to the Paskapoo Formation, and the word is Cree for 'blind man'.
Some of the material had previously been assigned to N. hunteri. |
| Reference: | Scott (2005), New neoplagiaulacid multituberculates (Mammalia,
Allotheria) from the Paleocene of Alberta, Canada, Journal of Paleontology, 79(6),
p.1189-1213. |
| Species: | Neoplagiaulax cimolodontoides Scott CS, 2005 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
This is a somewhat eccentric species, and it shares this characteristic with vertebrate
paleontologists. The lower p4 premolar has a higher, more
arched crown than other members of the genus (p.xviii), and there are other dental details
as well. Some of those are similarities reminiscent of a North American multi called
Cimolodon, which isn't a member of the neoplagi family.
These are matters of convergence. It's particularly unusual for more welcome reasons.
Exceptionally for neoplagis, it saw fit to supply reasonably generous portions of its skull.
The animal also donated information on patterns of tooth replacement.
Skull
Most information on ptilodontoid heads had been provided by specimens of
Ptilodus montanus and fragments from
Prochetodon cavus, Ectypodus tardus and
Krauseia. Three fossils of N. cimolodontoides
(including the holotype) have added much to the knowledge of neoplagi ptilodontoids;
specifically the maxilla, part of the
zygomatic arch of the cheek region and the secondary
bony palate. Crushing and fracturing blur some details but beggars and lovers of ancient
mammals can't always be choosers.
A process of the maxilla helps build the front of the zygomatic arch (aka cheek bone), and
this begins close to the final premolar. Unfortunately, this process is the only part of
the arch available. Another piece of the maxilla is termed the palatal process, and this
commences just behind the first premolar (p.xix), and
continues until in front of the alveolus for the second
molar. This palate is relatively broad, and there's a naturally
occurring hole in it between the P3 and 4; a so called vacuity. Such vacuities are popular
with various mammals, but evidence for them in neoplagis hadn't previously been available.
It's similar to what's known from Ptilodus montanus, while being shorter and broader
than in a specimen of Ectypodus tardus. Another feature is an odd pocket in the bone
at the front of the palatal process. Something of the like also occurs in Ptilodus,
but quite what this housed is unclear. One possibility is some form of gland.
Upper premolars
The front three of the four premolars resemble those described for both N. hunteri
and N. serrator, but there are some contrasts (p.xx). For one thing, these ones are
a bit bigger. More importantly, the enamel contains ridges with vertical grooves between
them, with the grooves strongest near to cusps. This effect is also present for a number
of cimolodontid and ptilodontid
multis.
The P1 has a triangular arrangement of a front cusp and two rear ones. The pair on the
labial side are triangular in cross section, whereas the single,
lingual one is more like a cone. The crown's supported by
two thick roots. P2 is fairly similar in most regards, but P3 is a bit bigger and has a
more quadratic outline. This crown is also set a touch lower than the others. It's got two
rows of cusps. In all cases, these teeth are relatively long, and an elongation at the rear
on the lingual side is packed closely with the front of the following tooth.
The most common cusp formula for the P4 is given as (0)0:8:0 (labial to lingual), but
another cusp is sometimes located in both the labial and middle rows. In various regards
this premolar is similar to the corresponding tooth of N. hunteri. These include
proportions of height compared to length, and a relatively straight middle cusp row.
However, P4s for N. cimolodontoides are narrower, and a lobe at the front of the
labial side is weaker. This sometimes houses a very small cusp, whereas that feature is
usually larger in the other mentioned species. As with the rest of the upper premolars,
the enamel has ridges and grooves. Wear is strongest to the rear of the tooth, and the crowns
have often been flattened behind the fourth or fifth cusp.
Upper molars
The cusp formula for M1 (2 specimens) is 7:12-13:8 (buccal
to lingual), and the
occlusal outline approaches a rectangular shape. Buccal cusps become larger from front
to back excepting for the rearmost one (p.xxi). Their internal slopes have deep grooving as
known from N. hunteri. The middle cusps are crescentric and also increase
progressively in size along the line. The internal row covers most the margin of the tooth
and again, they became larger towards the rear, although the final pair are similarly
sized.
One second molar provides a cusp formula of 3:6. The proportions of length and width make
it relatively longer than for N. hunteri, the lingual row has more cusps, and the
grooving on the slopes facing the central valley is deeper.
Upper replacement
As evidence of replacement patterns is provided by the holotype, this animal can't have been
an adult. Sadly, it never got to experience the baby-making stage. Information on
replacement hadn't previously been available for the genus. When the cold hand of death
rudely intervened, our young friend had the first three upper premolars in various stages
of their careers, P4 and M1 were well-established and the second molar was close to taking
on full duties. Wear on the P4 indicates it had already seen action for some time.
Furthermore, the anterior premolars are morphologically consistent with secondary teeth,
and not with milk ones.
P1 is at an early stage of development as it's not far above the
alveolus. P2 is close to complete, but the crown hasn't yet come into contact with the
following P3. It had a bit more growing to do. There is contact between the P3 and P4,
that Eagle had landed and wear demonstrates this tooth was operational.
All that suggests the permanent upper premolars appeared in the following order: P4, P3, P2,
P1. Quite when the first molar made its debut is unclear, but it was after P4 and before
M2.
Lower jaw
A couple of partial dentaries were collected (p.xxii), and
they allow a composite reconstruction of much of the jaw. The tooth-bearing ramus is shorter
and shallower than known from N. serrator and N. paskapooensis, and this is
valid in both absolute and proportional senses. Details concerning the incisor alveolus
show that tooth was less procumbent in the case of this species. Towards the back, the
coronoid process arose slightly further forward from the
buccal side of the m1 than for the other two species, and it probably ascended a bit
more gently than was the case with N. serrator.
Lower incisors
The holotype has remains of two incisors on one mandible;
a deciduous one and its senior replacement. This is a
novelty for the genus. The milk tooth is represented by parts of its root, and these are
positioned in front off, and a bit labial too the erupting
incisor. Some of the crown is also preserved. It was smaller than the permanent tooth
and less curved. Enamel thins towards the rear.
A permanent i1 is long and thin, but shorter when compared with N. serrator. However,
it's robuster and has more similarity with N. paskapooensis.
Lower premolars
There are two premolars per side but, predictably, the first (p3) is a pathetic peg, which
snuggled uselessly away into a cave provided by the frontal base of p4.
The lower slicing action was all concentrated on the p4. It's got a relatively high blade
for the genus, and is to some degree reminiscent of several
cimolodontids including Anconodon and
Cimolodon. Seen from the
occlusal perspective, the tooth is a trapezoid with the front being wider than the
rear. The highest point is located at the fourth (or sometimes fifth) serration. There are
usually 13 of these notches, but one less occurs in some cases (p.xxiii).
The blade begins with a relatively gentle ascent in contrast to N. serrator, and the
first serration is found at a higher level, more in keeping with N. paskapooensis.
Serrations increase in size after the sixth. Ridges run from them onto both the
labial and lingual faces, but
they're obscured by wrinkling in the enamel for the final two or three. The tooth is
double-rooted, with the front root being bigger and stronger than the rear one.
Lower molars
The usual cusp formula for m1 is 10:4 (buccal -
lingual), but some variation occurs for both rows. As
for N. hunteri, the outline of the crown approaches a triangular shape, but the tooth
is proportionately wider for N. cimolodontoides. As the rows of cusps don't diverge
as much along their course from front to rear, the width of the crown remains more stable.
The cusps themselves are also relatively wider. The lingual ones are relatively low for the
genus, the height of cusps in both rows is closer to parity, and the valley between the rows
is comparatively broad. Wear has left grooving on the buccal faces of buccal cusps. The
lingual row is composed of four to five strong cusps, with the first being a bit smaller
than the rest. The slopes facing the valley are deeply grooved while the rounded, lingual
faces aren't (p.xxiv).
The shorter m2 has a cusp formula of 6:3. Distinctions from N. hunteri are few.
It's a bit smaller and bears one more lingual cusp. The strongest grooves on these cusps
occur as with the first molar.
Lower replacement
Parts of both lower mandibles have been provided by the kind-hearted holotype kid, and the
left one shows the secondary incisor emerging. It's at an
early stage as it's only just above the rim of its alveolus.
The p4 premolar is already in place, though it's a bit low
when compared with that tooth in other individuals. It's not quite reached its final
adult state. (I suppose the fact that the animal's dead might be taken as contradicting
that statement.) An absentee with reference to the type fossil is the fairly pointless p3,
which hadn't erupted. As m1 is present, that tooth also appeared before the p3. Direct
information isn't available concerning the eruption sequence of the second lower molar, as
the juvenile with careless with the relevant jaw part. However, its upper counterpart was
near to ready for business, and it would be surprising if the lower partner hadn't reached
a broadly similar stage.
Assuming the inference about the m2 is correct, that suggests the following sequence: di,
p4, m1, m2, p.6.
Affinities
N. cimolodontoides has unusual teeth for the genus, but they do fall within the
established diagnosis (p.xxv). The closest matches presently known are from the mouths of
N. hunteri and M. mckennai. However, this species has too many specialisations
to allow for any particularly close association (p.xxx).
Holotype
The type fossil, UAL VP 42601, is a crushed skull and partial
dentary imprisoned at the University of Alberta, Edmonton. The specific name reflects
some dental parallels with Cimolodon, a non neoplagi
multituberculate. |
| Reference: | Scott (2005), New neoplagiaulacid multituberculates (Mammalia,
Allotheria) from the Paleocene of Alberta, Canada, Journal of Paleontology, 79(6),
p.1189-1213. |
| Genus: Parectypodus
Jepsen GL, 1930
'beside Ectypodus'
Aka : Ectypodus (partly); Mimetodon (partly); Neoplagiaulax (partly);
Perectypodus; Ptilodus (partly)
Remarks: A further nomenclatural nightmare. As with Ectypodus, this genus
is also known from the Eocene (Ypresian) of France.
| Reassigned species: P. childei (Kühne, 1969) see
Ectypodus childei and P. lunatus; P. clemensi Sloan,
1981 see Krauseia clemensi; P. jepseni Simpson,
1935 see Stygimys jepseni; P. lovei
Sloan, 1966 see Ectypodus lovei; P. pattersoni
Sloan, 1987 see P. sylviae; P. primaevus see
Mesodma primaeva; P. tardus Jepsen, 1930 see
Ectypodus tardus | |
| Species: | Parectypodus armstrongi Johnston PA & Fox RC,
1984 |
| Place: | Rav W-1, Saskatchewan |
| Country: | Canada |
| Age: | Puercan, Lower Paleocene |
| Remarks: | A resident of Alberta University. |
| Reference: | Johnston & Fox (1984), Paleocene and Late Cretaceous
mammals from Saskatchewan, Canada. Paleontogr. Abt. A: Paläozool., Stratigr. 186,
p.163-222. |
| Species: | Parectypodus corystes Scott CS, 2003 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | upper Torrjonian - lower Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of Scott
2003, (p.747-750).
The holotype is an incomplete lower jaw. Further premolars
(p4s) and a lower molar (m1) have also been found. These
lower p4s have an average length of about 3,6mm and the crown possesses 14-15 serrations,
plus an incipient one. When viewed from the side, these teeth have distinctive profiles
which inspired the species name. 'Korystes' is Greek for 'helmeted' and 'crested'. The
other lower premolar, (p3), is verging upon insignificance. (It's preserved on the
holotype). Where present in cimolodontans, this tooth
was relatively small and unimportant. It's not known in later representatives of this
genus from the Eocene.
The size of the p4s suggests this species was larger than P. vanvaleni and P.
sloani. However, it seems to have been much smaller than P. trouverssartianus
and P. armstrongi.
The holotype (UALVP 40679) comes from Diss Locality and also has the two lower molars.
Along with isolated teeth from the Who Nose? fauna, it's
in the collection of the University of Alberta. Both sites are in the same formation.
There may be a second, undescribed species present at Who Nose?. A formal description
awaits further specimens. |
| Reference: | Late Torrejonian (Middle Paleocene) mammals from South Central
Alberta, Canada. Journal of Paleontology, 77(4), p.745-768. |
| Species: | Parectypodus foxi Storer JE, 1991 |
| Place: | Frenchman Formation, Saskatchewan |
| Country: | Canada |
| Age: | Maastrichtian, Upper Cretaceous |
| Remarks: |
P. foxi is both the earliest and least derived
member of this genus, to which it might not belong. "While it is possible that
Parectypodus foxi is closely related to species of Cimexomys, it is equally
likely that the existing specimens, characters used, and taxa
included in this study are inadequate to distinguish Parectypodus from
Cimexomys", (Weil 1999, p.63). Weighed around 80g. |
| Reference: | Storer (1991), The mammals of the Gryde local fauna,
Frenchman Formation (Maastrichtian: Lancian), Saskatchewan. Journal of Vertebrate
Paleontology, 11 (3), p.350-369. |
| Species: | Parectypodus laytoni (Jepsen GL, 1940) Sloan RE,
1966 |
| Aka: | Ectypodus laytoni Jepsen, 1940 |
| Place: | Princeton Quarry, Wyoming |
| Country: | USA |
| Age: | lower Tiffanian, Middle-Upper Paleocene |
| Remarks: | Descendant of P. sinclairi, (Burkitt JH).
Specimens, including the holotype, are in the Peabody collection. A mini of 10g. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Pro. Amer. Philos. Soc, 83, p.217-340, 21 figs., 5pls. |
| Species: | Parectypodus lunatus Krause DW, 1982 |
| Aka: | P. childei (Kühne, 1969) |
| Place: | Pocket Quarry, Colorado & Wyoming |
| Country: | USA |
| Age: | Wasatchian, Lower Eocene |
| Remarks: |
Ectypodus childei? A specimen is in the collection of the
AMNH, New York. A Yale specimen is summarised as follows: Ectypodus tardus? =
Parectypodus sp. = Parectypodus tardus Jepsen, 1930 = Ectypodus simpsoni
(Jepsen, 1930) = Parectypodus lunatus. Be that as it may, the critter weighed about
20g.
Unclear
One point presently eludes my comprehension. P. childei was originally
known as Charlesmooria childei. It was based upon remains from Abbey Wood
in London, and these are now more generally regarded as belonging to
Ectypodus. I don't know why it also appears
as a synonym for this species. There's naturally the possibility of some other
remains described subsequently (?Wyoming). |
| Reference: | Krause (1982), Multituberculates from the Wasatchian Land-Mammal
Age, Early Eocene, of Western North America. J. of Paleont. 56, p.271-294. |
| Species: | Parectypodus simpsoni Jepsen GL, 1930 |
| Aka: | Ectypodus simpsoni Jepsen, 1940 |
| Place: | Wyoming |
| Country: | USA |
| Age: | Lower Eocene |
| Remarks: |
Descendant of P. laytoni, (Burkitt JH). Some fossils are
in the Peabody collection, including the holotype. This genus began its career as P.,
was rediagnosed as E., and then reverted to being P., with the assistance of
Sloan, 1966. How that should be correctly written is of no great interest to me. It weighed
around 35g. |
| Reference: | Jepsen (1930), New vertebrate fossils from the lower Eocene of
the Bighorn Basin, Wyoming. Proc. Am. Phil. Soc. LXIX, p.117-131. |
| Species: | Parectypodus sinclairi (Simpson GG, 1935) Sloan,
1966 |
| Aka: | Ectypodus sinclairi Simpson, 1935; Ptilodus sinclairi
Simpson, 1935d |
| Place: | Gidley Quarry, Montana & Wyoming & Alberta |
| Country: | USA & Canada |
| Age: | Puercan-Torrejonian, Paleocene |
| Remarks: |
Derived from Mesodma formosa, (Burkitt JH). A small 16
grammer. This is surely also known as Liotomus sinclairi. |
| Reference: | Simpson (1935), New Paleocene mammals from the Fort Union of
Montana. Proc. US Nation. Museum 83, p.221-244. |
| Species: | Parectypodus sloani Schiebout JA, 1974 |
| Aka: | Ectypodus sloani |
| Place: | Big Bend, Texas |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | |
| Reference: | Schiebout (1974), Vertebrate paleontology and paleoecology of
Paleocene Black Peaks Formation, Big Bend National Park, Texas. Texas Memorial Museum Bull.
24, 1-88. |
| Link:
Carbonate Nodule Conglomerate Fossil Sites
http://www.nhm.ac.uk/hosted_sites/pe/1998_2/schiebt/carbon.htm
A somewhat technical article on how to find mammal fossils at sites such as Big Bend. In
this case, an ordinary oven was involved. My wife tried something of the sort with
limestone from northern Franconia. It didn't work. |
| Species: | Parectypodus sylviae (Rigby JK, 1980) Sloan,
1987 |
| Aka: | Ectypodus sylviae Rigby JK, 1980; ?Ectypodus aphronorus
Sloan RE, 1987; P. pattersoni Sloan, 1987; ?Ptilodus sinclairi
(Simpson GG, 1935) |
| Place: | Swain Quarry and
The Breaks, Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | Body weight guestimate, 15g. In 1998, Secord
synonymized pattersoni with sylviae, although the former specific name is
still in use, (eg. Higgins, 2003). I suspect this was a mercy-killing.
A partial lower jaw and further isolated teeth from the Canadian location of
Who Nose? have been referred to cf P. sylviae,
(Scott 2003, p.747). These specimens are: "similar to material described by Rigby
(1980) from Swain Quarry, differing only in p4 having a smoother, more arcuate anterior
profile." (That's the large, lower premolar.) The
upper P4s are also virtually identical. |
| References: | Rigby (1980), Swain Quarry of the Fort Union Formation, middle
Paleocene (Torrejonian), Carbon County of Wyoming: geologic setting and mammalian fauna.
Evolutionary Monographs, 3, p.1-179. |
| Sloan (1987), Paleocene and latest Cretaceous mammals, rates
of sedimentation and evolution, p.165-200 In Fassett JE & Rigby JK (eds.), The
Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado.
Geological Society of America Special Paper, 209. |
| Species: | Parectypodus trovessartianus (Cope ED, 1882)
Van Valen & Sloan, 1966 |
| Aka: | Mimetodon trouessartianus Jepsen, 1940; Neoplagiaulax
trouessarti; "P. trouessarti"; Ptilodus trouessarti;
Ptilodus trouessartianus Cope, 1882 |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan-Torrejonian, Paleocene |
| Remarks: | Body mass of around 90g. |
| Reference: | Cope (1882), Synopsis of the Vertebrata of the Puerco Eocene
epoch. Proceedings of the American Philosophical Society, 20, p.461-471. |
| Species: | Parectypodus vanvaleni Sloan RE, 1981 |
| Aka: | Liotomus vanvaleni |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | I don't know who might have referred this species
to Liotomus, when, or indeed whether. Such an interpretation doesn't seem to be in
line with present thinking, (eg. Scott, 2003). |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates from
the San Juan Basin, New Mexico, pp. 127-160, in Lucas et al (eds), Advances in San Juan
Basin paleontology. University of New Mexico Press, Alberquerque. |
| Genus: Xanclomys Rigby JK,
1980
Aka: Xancolomys; Xandomys |
| Species: | Xanclomys mcgrewi Rigby JK, 1980 |
| Place: | Swain Quarry, Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | Affinities are uncertain. There's perhaps a
second, unnamed species scurrying around somewhere. |
| Reference: | Rigby (1980), Swain Quarry of the Fort Union Formation, Middle
Paleocene (Torrejonian), Carbon County, Wyoming: geologic setting and mammalian fauna.
Evolutionary Monographs, 3, vi+179pp. |
| Genus: Xyronomys Rigby JK,
1980
Aka : Xironomys
Remarks: Material has been reported from Rav W-1, Saskatchewan. The genus may belong to
Eucosmodontidae. However, according to more recent research, it doesn't seem to. |
| Species: | Xyronomys swainae Rigby JK, 1980 |
| Place: | Swain Quarry, Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: |
Represented by a couple of teeth, this genus was originally
assigned to Eucosmodontidae. Kielan-Jaworowska and Hurum (2001, p.406) refer it to
Neoplagiaulacidae, on the basis of its possession of microprismatic tooth enamel.
Fragments of lower premolars, (p4s), has been recovered
from the Who Nose? locality, Calgary, which compare well
with this species. However, some slight differences suggest they might represent a
different species, (Scott 2003, p.747). Scott also tentatively refers an upper P4 to this
genus; a tooth which is presently unknown for sure from X. The Calgary fossils,
(which work in the University of Alberta), are the earliest record of Xyronomys in
Canada. |
| Reference: | Rigby (1980), Swain Quarry of the Fort Union Formation, Middle
Paleocene (Torrejonian), Carbon County, Wyoming: geologic setting and mammalian fauna,
Evolutionary Monographs, 3, p.1-179. |
| Species: | Xyronomys robinsoni (unpublished name) |
| Place: | Colorado |
| Country: | USA |
| Age: | lower Puercan, Lower Paleocene |
| Remarks: | |
| Reference: | |
| Other reports:
News from Europe
The following is based upon my reading of Delsate, 2000 and Smith & Smith, 2004.
Thanks are due to the supplier. It should also be held in mind that both papers
happen to be in my French, and that's a language I happen to speak like a native...
of a non-French speaking country. I've tried my best and much appreciated the
assistance provided by summaries in English. Still, c'est la guerre.
Delsate, 2000 concerns two multituberculate
premolars. They were assigned to a neoplagiaulacid (p.61), and this remains
undisputed. Doubts have been expressed concerning the locality of origin and
hence their ag. Smith & Smith, 2004 cited problems.
Should you wish to be unclear about where parts of your fossil collection were
actually found, then it could be a good idea to get somebody else to acquire them.
That's what happened with this instance. The specimens available to Delsate from
the Belgian locality of Dormaal had been picked up by G Wouters in 1964-65. As he
died in the 1980s, asking him for further information wouldn't be overly
successful. The Smiths conclude that the sediment from Dormaal, a locality dating
from the Paleocene-Eocene transition, has in at least one instance been mixed with
material collected from a somewhat later location in the Paris Basin.
The mammlian teeth believed to be from Dormaal by Delsate provide a relatively low
proportion of the relevant specimens from there, (assuming that was the source).
They contributed 250 to a total of about 14,000. A surprisingly high number of
taxa hadn't previously been found either at that place
or, for that matter, anywhere else in that part of the European Eocene. However,
they do occur in later European faunas. A similar situation exists for several
fish in the new collection.
The key words the Smiths selected for their paper leave no doubt about their
confidence: "Dormaal, Delsate collection, contamination". The locality, first
discovered in 1883, has been extensively sampled both before and since 1964-65, and
nor further specimens of any of the disputed taxa have ever come to light there.
It's little wonder that they're confident.
A bit younger?
In the esoteric language employed by researchers of the subject, Dormaal is part of
the MP7 of the mammal biochronological scale representing the European Paleogene.
The relevant mammals are otherwise known from MP8-9 of the Middle Ypresian. Rather
than dating from the Paleocene/Eocene border, these particular fossils are
probably Eocene.
Assuming the Smiths to be correct, I confess to feeling a measure of pleasure that
has absolutely nothing to do with any Schadenfreude at a mistaken
interpretation. Although only two premolars of a multi were among the Delsate
Collection, they're from a multi of the European Eocene; a relatively late survivor
of a proud tradition stretching back well over 100 million years. The earliest
undisputed multi fossils date from the Middle Jurassic. This isn't the first
instance of a Euopean Eocene multi, but they're far from ten a penny. Their lineage
was richly diverse during the Paleocene (especially in North America), but it then
drastically dwindled. For examples, despite boasting of getting on for fifty
different species of mammal, the fabulous German site of Messel hasn't yielded
multis at all. However, it should be said that there's a rather curious shortage
of small fry there, excepting for bats. Typically, multis were smallings.
Affinities
Regardless of where they quite come from, assigning the two relevant fossils any
more precisely than to some neoplagi or other is thrawted by their inadequacies.
They happen to be partial upper premolars from relatively forward positions of the
tooth row; probably a P1 and a P2 or P3. Such teeth are considerably simpler and
less informative than rear premolars or molars. Nevertheless, they do signal a
small multi presence in the Eocene of (presumably) France.
Addtional Eocene Euro-multis
Already recorded are: Ectypodus and
Parectypodus from the Ypresian of France and
"Parectypodus" childei from Abbey Wood, London. The latter was given
the name of Charlesmooria. |
A. Neoplagiaulacidae & Neoliotomus B.
B. Ptilodontidae C. Cimolodontidae
| Taxon: Ptilodontidae (Cope ED, 1887) Gregory & Simpson, 1926
And a lot more names for multituberculate teeth. This grouping has also been seen as a
subfamily; Ptilodontinae (Cope, 1887). Chirogidae Cope ED, 1887 is a synonym.
Reference: Cope ED, (1887), The marsupial genus Chirox. American Naturalist, 21,
p.566-567.
Genera: Baiotomeus, Chirox (= Ptilodus),
cf. Ectypodus (partly = Ptilodus), Kimbetohia,
Litotherium (a Paleocene primate tentatively misassinged to the family),
Mimetodon (partly = Baiotomeus), Neoplagiaulax (partly = Baiotomeus),
Prochetodon, Ptilodus
(partly = Baiotomeus), other reports
Time-Line:
Eocene: Prochetodon
Paleocene: Baiotomeus, Kimbetohia, Prochetodon, Ptilodus
Upper Cretaceous: Kimbetohia |
| Genus: Baiotomeus Krause DW,
1987
Aka: Mimetodon (partly); Neoplagiaulax (partly); Ptilodus (partly)
Reference: Krause (1987), Baiotomeus, a new ptilodontid multituberculate
(Mammalia) from the Middle Paleocene of western North America. J. of Paleont.61, p.595-603.
|
| Link:
Teresa Elsie MacDonald
http://www.athene.freeserve.co.uk/teresa/teresamsc.htm
Late Paleocene (Tiffanian) mammal-bearing localities in superposition, from near Drumheller,
Alberta. The abstract of a MSc degree thesis under the auspicious of the University of
Alberta. |
| Species: | Baiotomeus douglassi (Simpson, 1935) Hartman, 1986
|
| Aka: | Mimetodon douglassi Jepsen, 1940; Neoplagiaulax douglassi
Schiebout, 1974; Ptilodus douglassi Simpson, 1935d |
| Place: | Gidley Quarry, Montana & Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | A fairly substantial multi of near 200g. How
this could have been referred to Baiotomeus in 1986 is something I don't understand.
Krause formally established the genus in 1987. Life's full of mysteries. |
| Reference: | Simpson (1935), New Paleocene mammals from the Fort Union of
Montana. Proc. US Nation. Museum 83, p.221-244. |
| Species: | Baiotomeus lamberti Krause DW, 1987 |
| Aka: | Mimetodon sp.; Ptilodus montanus? |
| Place: | Medicine Rocks, Tongue River Formation, Montana &
Wyoming |
| Country: | USA |
| Age: | Tiffanian, Paleocene |
| Remarks: | Several specimens, including the holotype, are at
the Peabody. Collected in 1958 and 1965, these were originally described as belonging to
Mimetodon. |
| Reference: | Krause (1987), Baiotomeus, a new ptilodontid multituberculate
(Mammalia) from the Middle Paleocene of western North America, Journal of Paleontology, 61,
p.595-603. |
| Species: | Baiotomeus rhothonion Scott SC, 2003 |
| Place: | Who Nose?, Paskapoo Formation,
Alberta |
| Country: | Canada |
| Age: | upper Torrejonian, Paleocene |
| Remarks: |
The following is based upon my understanding of Scott, 2003
(p.751).
"Smallest species of the genus, p4 length approximately 57 percent less than p4 of B.
douglassi (Simpson, 1935), 51 percent less than p4 of B. lamberti Krause, 1987, 20
percent les than p4 of B. russelli Scott, Fox and Youzwyshyn, 2002".
The cutting edge of the main lower premolar is equipped
with eleven serrations, as well as an incipient one. These become larger and chunkier the
further back on the tooth they're located. The relatively small size of the fossils is one
reason for the establishment of a new species. Another is the distinctive profile of these
premolars. This is described in terminology which presently defies my comprehension.
The type fossil is a lower, left premolar (a p4). Along with some further isolated upper
and lower choppers, UALVP 44132 lives in the University of Alberta Home for Stray Fossils.
The species name is Greek. It translates as small nose and refers both to the small size
of the species and the Nose Creek, next to the Fundstätte. |
| Reference: | Scott CS (2003), Late Torrejonian (Middle Paleocene) mammals from South Central
Alberta, Canada. Journal of Paleontology, 77(4), p.745-768. |
| Species: | Baiotomeus russelli Scott CS, Fox RC &
Youzwyshyn GP, 2002 |
| Place: | Cochrane 2, Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | earliest Tiffanian, Paleocene |
| Remarks: |
The following is based on my reading of Scott et al 2002, (with
thanks to the APP).
Remains consist of nine upper premolars, (P4), which
average out to nearly 2,5mm in length. They're smaller than the teeth of other genus
members (update: they're larger than those of B. rhothonion, but that hadn't been
published when I initially wrote this); in terms of anteroposterior length approximately
45% less than B. douglassi and 40% below B. lamberti. The rows of cusps also
display a strong curvature and the "cuspate anterolabial lobe" is better
developed, (whatever it might be). Oh, and there's more variation in the height of the
cusps among the middle row. (Shame you haven't got a photo.) These particular premolars
-P4s- have three rows of cusps, of which there seem to be about 15 or so in all. Anyway:
"The enamel is weakly wrinkled on all specimens", (p.695).
The authors add: "At present, P4s are the only specimens from Cochrane 2 that we can
identify as pertaining to B. russelli. Although knowledge of this species is limited,
we consider its naming to be justified based on the diagnostic morphology of ultimate fourth
premolars in ptilodontids generally (Krause 1982, 1987) and the unique structure of these
teeth."
The species name honours Russell LS: "for his pioneering research on the mammals from
Cochrane 2." All presently identified remains are part of the collection of the
University of Alberta.
Cochrane 2 has also been interpreted as correlating to the Porcupine Hills Formation, but
recent studies suggest it's part of the Paskapoo, as originally concluded by Russell LS in
1929. The paper also contains descriptions of new eutherian
taxa; Litomylus grandaletes, Pararyctes
rutherfordi and Paleotomus junior; and a pair of new assignments;
Thryptacodon orthogonius (Russell, 1929) and Bessoecetor septentrionalis
(Russell, 1929), which are also both referred to Eutheria, though the latter fossils have
been seen as marsupials by others. These are outside
the scope of this project. |
| Reference: | Scott, Fox & Youzwyshyn (2002), New earliest Tiffanian (late
Paleocene) mammals from Cochrane 2, southwestern Alberta, Canada. Acta Palaeontologica
Polonica 47 (4), p.691-704. |
| Genus: Kimbetohia Simpson
GG, 1936
'for Kimbetoh'
Aka: Kimbetohi
Remarks: Kimbetoh is described as a: "well-known arroyo and trading post near the
type locality". Remarkably or otherwise, it's not well known by we residents of
Dipwytch. We've heard
of many wonderful hamlets and villages, but that one's not on the county map in our
Village Hall. Still, George Simpson doubtlessly knew the place. It's in New Mexico. |
| Species: | Kimbetohia campi Simpson GG, 1936 |
| Aka: | K. cambi |
| Place: | Nacimiento Formation, San Juan Basin, New Mexico & Wyoming |
| Country: | USA |
| Age: | Upper Cretaceous (Maas.) - Paleocene (Puercan) |
| Remarks: | The following is based upon my reading of Simpson,
1936 (which is listed as 1936b in the Bibliography of my directories).
Before turning to Kimbetohia, one diagnosis in this study is credited to WD Matthew,
and the paper was originally intended as an appendix for a delayed publication by Matthew
(p.1). One of the circumstances to intervene with that project was death. Unless I've
overlooked something, Simpson wrote the rest and is listed as the sole author. The study
only concerns additional taxa from Paleocene faunas in the
San Juan Basin of New Mexico, which were found by a 1929 AMNH expedition and two field
campaigns from the University of California (1928 and 1930).
Introducing K. campi
The described fossil was a fragment from the right skull with three upper
premolars. Simpson uses some fairly spectacular words
for the positions, and I assume this reflected some uncertainty concerning the original
number of those teeth. He's certain there were four, but that wouldn't have necessarily
precluded the possibility of more (p.2). 'Ultimate' is familiar enough and 'penultimate'
not too bad, but I'm not all that keen on 'antepenultimate'. Sadly, the other position
receives no such accolade. (I was hoping for 'preantepenultimate' or some such.) I think
I'll try struggling through with terms such as 'foremost', 'middle' and 'last' for the
holotype teeth. Although four is the minimum number, only the latter three premolars are
actually preserved.
Kimbetohia was a cute mini-multi, which scampered around in the early days of the
post-Cretaceous world, perhaps wondering where all the bigglings had gone. All known
mammals of the lower Paleocene were less than
middling-sized (in comparison to the mammals of our time), but Kim took smallness more
seriously than most.
Premolars
The foremost preserved tooth has one buccal and two
lingual cusps, and the crown is wider than its length. Its
neighbour is marginally smaller, a sort of roundish-squarish hybrid shape, and dressed with
a cusp in each (roundish) corner. The last premolar is the largest, and it nudges to
three cusp rows. The lingual line's 'well-developed', the next 'nearly complete', and the
buccal 'incipient'. The incipient row consists of a solitary cusp, which is the equivalent
of an unusually hectic queue at a bus stop in the middle of Antarctica.
The lengths of the three teeth are as follows (from front to back): 1.9mm, 1.7mm, 4.1mm.
Local context
The interest of this specimen was enhanced, as it was very different to any previously
discovered remains from the area. Up until then all local multis had been either
Taeniolabis or
Eucosmodon; both rather specialised for one reason or another. Kim was a more
mainstream generalist, and the apparent lack of such critters from the fauna had been a bit
of a puzzler.
Comparisons
Contrasts with Taeniolabis were too extreme to merit discussion. Comparisons with
local Eucosmodon fossils were hampered by the lack of upper teeth from that time.
However, Kimbetohia was a lot smaller than any known E. species from either
the Puercan or Torrejonian, and differs from available teeth of that later time. The
middle preserved premolar is both proportionately small and generally simpler. Last upper
premolars assigned to Eucosmodon had: "only one complete row of cusps and one
very incomplete row." The Torrejonian versions probably possessed only three of these
teeth, whereas Kimbetohia had four.
Simpson notes the size is comparable with what was then E. gratus, but upper premolars
weren't available for that species. (Subsequently, material of that species has been
transferred to Cimexomys gratus and
Stigymys kuszmauli. E. gratus is
deceased.)
Holotype
The type fossil is a fragment of bone which was, and presumably still is, in the collection
of the University of California. The catalogue number was 31305. Its specific name
honours Charles L Camp, who collected it along with Vander Hoof. (A condylarth receives
the name Tiznatzinia vanderhooferi on page 8.)
Home Sweet Home
The collection site is written as Bitonitsoseh Arroyo, but that's not necessarily the
correct spelling. It's a Navajo word, and this is Simpson's rough approximation for the
place, which is located between Kimbetoh and Escavada. It had previously been referred to
as 'a nameless arroyo' and Eduardo Arroyo, but not by people who lived there. Local
residents generally have the best knowledge regarding the name of their home, so Simpson
sensibly accepted their word on the subject, regardless of never having seen it transcribed
into English.
In addition
Subsequently, some material was referred to Clemensodon megaloba Krause DW, 1992. |
| Reference: | Simpson (1936), Additions to the Puerco fauna, Lower Paleocene.
American Museum Novitates 849, p.1-11, 6 figs. |
| Species: | Kimbetohia? mzaie (unpublished) |
| Place: | Denver Formation, Colorado |
| Country: | USA |
| Age: | lower Puercan, Lower Paleocene |
| Remarks: | |
| Reference: | |
| Genus: Litotherium Simpson
GG, 1929
'frugal beast'
Remarks: Very concisely put, this was incorrectly and tentatively assigned to the family.
It's not any kind of multi.
The start of the generic name is explained as: "... from its want of prodigality in
leaving evidence of its existence". |
| Species: | Litotherium complicatum Simpson GG, 1929 |
| Place: | Fort Union Group, Bear Creek, Montana |
| Country: | USA |
| Age: | Upper Paleocene |
| Remarks: | The following is based upon my reading of Simpson,
1929.
What's that? keen fans of multis might ask. Simpson wasn't overly sure either, as he'd
never seen an upper premolar like it before. It's 3.2mm
long and 2.3 wide, blessed with three rows of cusps and made him think (p.9): "Its
affinities are doubtful, but it is very probable that it is a multituberculate of the
family Ptilodontidae. In no other group known to me do teeth even distantly similar
occur."
Not a multi
According to McKenna & Bell, 1997, the lack of obvious multi relatives has much to do
with the tooth actually belonging to Carpolestes; a carpolestid primate established
by Simpson in 1928. By some quirk of fate, he sets up a further species for that genus on
page 10, although the two specimens are both partial lower jaws with no upper counterparts
referred. I thought it merited a mention for the sake of completeness.
Holotype
The holotype, AMNH 22196, is in the collection of the American Museum of Natural History,
New York. The specific name refers to the form of the tooth. |
| Reference: | Simpson (1929), Third contribution to the Fort Union fauna at
Bear Creek, Montana, American Museum of Novitates, 345, p.1-13. |
| Genus: Prochetodon Jepsen
GL, 1940
Aka: Ptilodon? (partly)
The following is based upon my reading of Krause DW, 1987
Prochetodon is a poorly known
multituberculate mammal from North America, but at least one species managed to
do something most multis didn't. Its members (yes, this is a pun) were still having
sex during the Eocene and, by that time, the organs of most multis had fallen silent.
That's metaphorically meant, as I'm specifically thinking about sex organs and not
early Wurlitzers. One of the keys to reproductive success is being alive, and few
multis possessed that qualification beyond the Paleocene, which ended about 55 million
years before the first cinema opened. (A note for younger readers. Cinemas are
places where they show DvDs and videos on large screens and, at one time in the
ancient days, these were sometimes accompanied by an organ player. Oh, now I'm
writing specifically about Wurlitzers and not sex. The latter was generally taken
care of by patrons in the back row of seats.) Anyway, that was the odd trailer and
now we'll have a quick interlude for a recap: Prochetodon, poorly known but
late multi mammal, North America. And, if everybody got their popcorn ready, the
film's about to begin.
A Star is Born
Prochetodon is a relatively rare mammal in terms of the number of fossils, but
it had a fairly wide screen geographical range (p.221). When the genus was established
in 1940, the few specimens known came from a single locality in Wyoming, Princeton
Quarry. More material has subsequently been dug up from there, but also from at
least 32 other sites in Alberta, Saskatchewan, Montana, North Dakota and Wyoming.
It hasn't been found in the fossil mines of a similar age further south.
Krause, in 1987, reviewed the genus because of these further finds, and found it
necessary to increase the then species count from one to three. (A fourth was added
in 2004.) The fossils Krause had available date from a slice of time comprising
about 2.5 million years, from the late night picture show of the Paleocene until the
morning matinee screening of the Eocene. For aficionados of North American Land
Mammal 'Ages', that's middle Tiffanian - middle Clarkforkian (Ti3 - Cf2. For
non-knowists, think in terms of either side of 55 million years ago. Furthermore,
as the new material provided previously unknown information, it also brought the
opportunity to revise the diagnosis of both the genus and its senior species, P.
cavus.
Family Plot
Discussions with Prochetodon revealed it was closely related with
Kimbetohia, Baiotomeus
and Ptilodus (p.222). It's considerably larger than
the first pair but about the same size of heftier species of the third. Typical
ptilodontids have conical cusps on the buccal side of
the three front upper premolars, whereas these are
termed 'lenticular' for Proch. There are also differences in the arrangement of
cusps on the P2, rather a lot of them on P3, and the P4 is a relatively long and
narrow premolar. There are the distinctions for other teeth as well, but that
suffices to make the point that Proch is a separate genus for sound reasons.
The film will now carry on with episodes dedicated to each species below. |
| Species: | Prochetodon cavus Jepsen GL, 1940 |
| Aka: | Ptilodon sp. |
| Place: | Princeton Quarry, Wyoming |
| Country: | USA |
| Age: | Upper Paleocene - Lower Eocene |
| Remarks: | The following is based upon my reading of
Krause, 1987.
The Smallest Show on Earth
For no particular reason, most subheadings employed for this genus are references to
films, but they're not necessarily well known (which seems apt enough, given the
shortage of fossils) or overly appropriate (which could be inapt). Still, I've
always rather liked the 1958 British comedy alluded to here. The movie concerns the
worst cinema on the planet, and the mention of dimensions is about right. The point
I'm stating is, in a very long-winded way, that this species is small for the genus.
By the way, Peter Sellers played an often tipsy projectionist in the film, and the
resultant scenes based in Wyoming (or somewhere near) are delightfully silly.
Good, I've managed to spit out that it's smaller than P. foxi and P.
taxus (p.228), but not actually all that much smaller. The
buccal row of cups on the P4 upper premolar
reaches about the halfway line of the crown. It's cuspier than the equivalent tooth
of P. taxus but less so than P. foxi. The front of that premolar is a
bit lower than its rear, and this makes it proportionately lower than is the case
for P. taxus but taller than P. foxi. When originally described in
1940, the number of known molars was equal with the
number of unicorns in my attic. (Page 229 doesn't quite express it so. No molars
were known.) This may help to account for the diagnosis being centred on premolars.
New specimens have improved the situation, and allowed Jepsen's assignment of
isolated premolars to be checked. Particularly informative is part of a skull
including remains of both tooth rows, and these provided the right molars. It states
Jepsen was correct in associating the P3s and P4s. A couple of lower molars have
also deigned to posthumously erupt for this species.
Under the Yum Yum Tree
Krause only attended to information that was new. This included comparing the p4
lower premolar with those of other species (p.230). It's generally shorter, the
mesial margin is less rounded and (presently somewhat beyond my grasp) the
'exodaenodont lobe' is termed more distinct. Length (11 specimens): 6.6 - 7.7mm;
width (5 sp) 2.0 - 2.6; height (10 sp): 2.6 - 3.0.
The Bridge over the River Kwai
Specimens of all upper postcanine positions
were available. As well as further specimens, the partial skull was generous with
them. The unsurprising account (per side) is: 4 premolars and 2 molars.
A statistical summary of the upper premolars:
Premolars. P1 (6 specimens): length 1.9 - 2.4mm, width (5 sp) 1.5 - 1.6; P2 (5 sp): l 2.3 - 2.4,
w 1.7 - 1.9; P3 (8 sp): l 3.4 - 3.7, w (7 sp) 1.9 - 2.2, cusps (9 sp) 4:5:4; P4 (4 sp):
l 4.7 - 5.2, w (5 sp) 1.6 - 1.7, c (4 sp.) 2.5-5:10:0.
A similar account for the upper molars appears beneath
the next paragraph. Of these, the M1 isn't greatly different to the corresponding
tooth of Ptilodus (p.230). The fairly subtle distinctions apparent include
the buccal cusp row being proportionately narrower in
comparison to the central one, and the front end of the crown being rounder. For the
M2s, buccal cusps flare less broadly, the front and second of the middle row are
lightly connected, and the distribution of cusps in the
lingual row is more irregular. At least, the extreme specimens were found to
conform in a helpful way, but variation among individuals blurs these differences.
In practice, for isolated specimens from localities boasting both genera, these
tendential characteristics couldn't be used to separate the wheat from the
chaff. The wheat was too chaffy and the chaff too wheaty.
Molars. M1 (1 sp.): l 4.5mm, w 2.0, c 7:10; M2 (2 sp): l 2.0, w 1.9 - 2.0, c
1:3:3.
Holotype
YPM-PU 13925 is a right lower jaw with some remnants of teeth, and it's held prisoner
in the Peabody Penitentiary of Yale University. It was arrested at Princeton Quarry
in Wyoming, and has suffered from damage over the subsequent decades. All known
specimens (in 1987) came from localities in the same area, the Bighorn Basin. Should
you be seeking an explanation of the specific name, then please feel free to find one
elsewhere and let me know.
Additional notes
The critter weighed perhaps about 135g. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Pro. Amer. Philos. Soc, 83, p.217-340, 21 figs., 5pls.
|
| Species: | Prochetodon foxi Krause DW, 1987 |
| Aka: | Ptilodus sp. (partly); Prochetodon cf. cavus
(partly); Prochetodon sp. |
| Place: | Long Draw Quarry, Montana, & Wyoming & North Dakota &
Swan Hills, Alberta & Saskatchewan |
| Country: | USA & Canada |
| Age: | Tiffanian, Upper Paleocene |
| Remarks: | The following is based upon my reading of
Krause, 1987.
Brief Encounter
At its time of christening, the holotype was the only specimen to have been recovered
from the Long Draw Quarry (p.223), but it had the company of further fossils for the
species from localities in Saskatchewan, Alberta, Wyoming and North Dakota. The
critters had been scurrying about during the middle Tiffanian (Ti3 - Ti4).
In terms of the length of the main lower premolar
(p4), this species is a bit larger than the somewhat later Pro. cavus and
about the same time as the still later Pro. taxus. The
buccal side of the P4 (which is an upper tooth) has a longer and more populous
cusp row. This extends well beyond the halfway line of the crown, and involves a
team of up to eight cusps. The maximum observed for its sisters is but five. The
front of that tooth is considerably lower than the back, more so than for the sisters,
and the p4 below is also proportionately lower in comparison to its length.
The largest cast of fossils had been obtained from three sites in Saskatchewan, and
all of these are isolated teeth. As they'd already been described, Krause limited
his latest script to supplementary details on specimens from elsewhere.
What Lies Beneath
The lower dentition, according to the type fossil
(a partial jaw from Montana), just about had two premolars, p3 and p4. The first of
them is a pathetic slither of a peg, and its object in life seems to have been to
sit quietly and more or less uselessly beneath an overhang of its action-loving rear
colleague (p.224). It's something like a bouncer guarding the door of a long, fairly
low-roofed disco, and perhaps it managed to prevent something or other from falling
into the guttering of the flesh of the gum but, unless it meditated or philosophized,
than this p3 has already received far more words than its physique could possibly
justify. Let's just walk past it sneeringly to the p4.
The length range for p4 falls between 8.0 - 8.7mm, width 2.2 - 2.4 and height 2.9.
That means, in terms of ptilodontids, this tooth is long and low. It has a plentitude
of 15 serrations along its curved length, and the front edge of the tooth (mesial)
exhibits a smooth, roundly shaped edge. That feature is less rounded for P.
cavus.
Lower molars are gently massaged on page 227. Although the animal doubtlessly had
enough for its needs, only the m1 had been identified for this species. There are
half-a-dozen specimens with lengths running between 3.5 - 4.2mm and widths of 1.6 -
1.9. The cusp row counts can be summarized as 6.5-8 (labial) : 5 (lingual). (I'd
imagine '6.5' results from two cusps having merged, but I'm not sure, and those
figures come from page 225)
High Society
The known upper premolars referred to the species
from the Princeton Quarry are somewhat variable in cusp numbers. The
labial row of P2 mostly manages four cusps but, on
occasions, two of these are twinned. The same row on P3 favours five. The
corresponding characters for P. cavus are 3-4 and 4-5 respectively. Generally,
P. foxi is the cuspier in these regards, and this may simply be because the
teeth are a bit larger.
There are four premolars for each upper jaw, and they become progressively longer
(p.226). The cusp formulae for the final three (given as labial-lingual) don't
include the Princeton Quarry specimens just mentioned, and this results is some
differences to the above.
P1 (6 specimens): length 3.5 - 3.8mm, width 1.7 - 1.9; P2 (9 sp): l 2.5 - 2.8,
w 2.0 - 2.2, cusps 4; P3 (6 sp): l 3.5 - 3.8, w 2.0 - 2.2, c 5:4; P4 (3 sp): l 5.5
- 5.6, w 1.8 - 2.0, c 6.5-8: 11-12 : 0.
The species was even more impoverished for upper molars than it is for lowers. None
were known. An isolated M2 from one locality could perhaps belong, but it seems to
be too large (p.227).
Holotype
YPM-PU 21223 is part of a lower right jaw from Long Draw Quarry, Montana. It's a
guest of the Yale Peabody Museum, and the specific name honours Richard C Fox, a
professor at the University of Alberta. This is in recognition of both his work on
fossil mammals, and his influence on the larval stage of the author's career; ie.
when Krause was a student.
Additional notes
An estimate for the body mass is around 200g. |
| Reference: | Krause (1987), Systematic revision of the genus Prochetodon
(Ptilodontidae, Multituberculata) from the late Paleocene and early Eocene of western North
America, Contributions from the Museum of Paleontology, The University of Michigan, 27(8),
p.221-236. |
| Species: | Prochetodon taxus Krause DW, 1987 |
| Aka: | P. cavus (partly); P. cf. cavus |
| Place: | Clark’s Fork Basin, Wyoming |
| Country: | USA |
| Age: | Clarkforkian, Lower Eocene |
| Remarks: | The following is also based upon my reading
of Krause, 1987.
Sunset Boulevard
In terms of tooth size, this species is comparable with P. foxi and a bit
larger than P. cavus. Dating, according to Krause, from the Lower Eocene,
it's the last hurrah for this family -the most recently known species- and one of the
last squeaks of multidom. The earliest known traces of undoubted
multituberculate mammals have been found in
Middle Jurassic deposits of around 165 million years in age and here, 110 million
years later, the spotlights were shining on new stars as the former celebrity lay
helpless and hideous, gagging for one last time behind the dustbins. The classic
film ended and, after adverts for ice cream, a brash new movie begun to play with
younger actors known as rodents slightly more mature than Shirley Temple at the height
of her career. (Still later, they would include the notorious rat pack and
telephone-marketing primates.)
The distinctions between the species for this genus centre on the
premolars (p.232). The
buccal cusp row of the upper P4 has just about given up the ghost, and left a
solitary small cusp at the front. The anterior and posterior of its crown, mesial
and distal should you prefer, are more or less of the same height, unlike earlier
models. This means the front has been raised over the generations.
The number of available specimens was only half-a-dozen but one, the holotype, is
exceptionally informative for this genus; upper and lower jaws with teeth from the
self same snout.
Night of the Living Dead
Included on a lower jaw is the root of an incisor,
i1. The incisors for this genus were long, svelte teeth, and it's possible that an
isolated specimen from Buckman Hollow could be one of them, although certainty is
lacking.
Two p4 premolars were available: length 7.7 - 8.0mm, width 2.1 - 2.8, height 2.6 -
3.1. This tooth has a proportionately higher crown than do the earlier species.
Both lower molar positions were represented
, but
they weren't discussed in the study; m1 (2 specimens): length 3.9 - 3.9mm, width 1.7,
cusps 7:5; m2 (2 sp): l 2.1, w (1 sp) 1.9, c (1 sp) 3:2. I've omitted mention of an
isolated m2 with an estimated length.
High Noon
All upper postcanine positions are represented
thanks to the type fossil, and two further premolars were also identified.
Premolars: P1 (1 specimen): length 2.6mm, width 1.8; P2 (3 sp): l 2.6 - 3, w (2 sp)
2.0 - 2.2, cusps (3 sp) 4 - 4.5; P3 (3 sp): l 3.9 - 4.5, w (2 sp) 2.2 - 2.4, c 5:4;
P4 (2 sp): l 5.8 - 5.9, w 1.7 - 1.8, c 1:11:0.
While cusps numbers of P2 and P3 show differences between the various species, this
seems connected with their varying lengths. The larger species, unremarkably enough,
have longer premolars, and these provide more space for furnishings. This sort of
explanation can't account for the withering buccal
cusp row of P4. If the ages of the localities have been correctly assessed, and
fossil finds correlate with the chronological appearance of the species on Earth,
then the oldest of the trio under consideration is P. foxi, P. cavus
is somewhat more recent and P. taxus is the youngster. The buccal row of P4
depopulated from 6.5-8, down to 2.5-5 and finally 1. On the face of it, this
decrease in cuspiness can be sensibly termed progressive.
The only upper molars known were the four supplied with the type fossil. As they all
belonged to the same owner, there's minimal variation for each position, and the
sample size is 2 in all cases.
M1: length 5.2 - 5.3, width (2x) 2.3, cusps (2x) 8:10; M2: l 2.1 - 2.2, w (2x) 2.1,
c (2x) 1:3:3.
Love Story
According to the census provided by the fossil mines of North America, the randiest
ptilodontids were to be found in the genus Ptilodus.
Its bountiful bonkers produced much more diversity and many more babies than issued
from the loins on behalf of Prochetodon, Kimbetohia
or Baiotomeus (p.234). If love indeed makes the
world turn, then the average adult Ptilodus of the Paleocene may well have been
giddy but nevertheless satisfied. Despite mammal bearing fossil mines of the right
age being common enough south of Wyoming, Prochetodon doesn't seem to have
dropped dead in them. It was a northerner by habit and temperament.
The only evolutionary 'trends' detected over time concern the upper P4 premolar. The
number of buccal cusps diminished, and the front of the crown increased proportionately
in height. However, as the available samples were small for each species, actual
trends might not be faithfully represented by the apparent ones.
Holotype
The type fossil, UM 71311, is part of a skull studying at the University of Michigan.
The lower jaws were also recovered. Its specific name is Latin for 'badger', and
this reference is geographical rather than zoological, as the fossil came from an
area known as Badger Basin in the Bighorn Basin. (Perhaps that makes it a
basinnette.)
Additional notes
The Peabody has a couple of specimens. Weight of about 190g. |
| Reference: | Krause (1987), Systematic revision of the genus Prochetodon
(Ptilodontidae, Multituberculata) from the late Paleocene and early Eocene of western North
America, Contributions from the Museum of Paleontology, The University of Michigan, 27(8),
p.221-236. |
| Species: | Prochetodon speirsae Scott CS, 2004 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffaninan, Lower Paleocene |
| Remarks: | This is the oldest species yet discovered and
has characteristics intermediate between this genus and Ptilodus. |
| Reference: | Scott (2004), A new species of the ptilodontid multituberculate
Prochetodon (Mammalia, Allotheria) from the Paleocene Paskapoo Formation of Alberta,
Canada. Canadian Journal Earth Sci./Rev. Can. Sci. Terre, 41(2), p.237-246. |
| Genus: Ptilodus Cope ED, 1881
Aka: Chirox Cope ED, 1884; cf. Ectypodus (Jepsen, 1940);
Neoplagiaulax sp.
'feather tooth'
Remarks: About 30 - 50cm long with a 7,5cm skull, which is a relatively large multi.
According to the Tyrell Museum Homepage, "Ptilodus is a common Paleocene
multituberculate mammal. It possessed a large
shearing tooth on each side of its lower jaw. These teeth worked against the upper
molars to slice food prior to chewing, which was done
with the back teeth. Its incisors are long and project
forward but were probably not used to handle and pierce food. Ptilodus is known from
well-preserved skeletal material. Its feet and limbs are known to have been similar to
those of modern tree squirrels, and it is known to have had a long tail. It was almost
certainly a tree dwelling animal."
What a shame that none of this well preserved material is available on-line.
Ptilodus pyramidatus is an extinct Australian plant.
The 2004 meeting of the Society of Vertebrate Paleontology has produced an abstract on this
genus: Krause D, Systematic revision of the genus Ptilodus (Ptilodontidae,
Multituberculata) from the Paleocene of western North America. It would be a pity not to
take advantage of this.
This genus is undoubtedly the most well-known of the North American multis, and is also one
of the best known mammals of its day. The type species, P. mediaevus, was published
in 1881. Since then, paleontologists have persistently been raiding the western rocks for
further specimens. The sample of examinable teeth now runs into the thousands. Added to this
are bits of head and skeleton. The animal was 'small-brained', (that's not my phrase), and
its sense of smell was dominant. Ptilodus seems to have been a nocturnal omnivore
built for a life in the trees.
In some localities, this critter provides a fifth of all the mammal fossils available. It
was at the height of its popularity during the upper Torrejonian and through the Tiffaninan
times, (which translates into about 62 - 56 million years ago. Then it went out of fashion.
As material is relatively plentiful and much time has been available, the genus has also
grown messy. Species have proliferated. Krause makes the following assessment:
Seven species were recognized in a work in 1987, and a further one has since been published.
1. Six are supported here: P.tsosiensis, P. mediaevus, P. montanus,
P. wyomingensis, P. kummae and P. gnomus.
2. P. ferronenesis is put down, and seen as a junior synonym of P. mediaevus.
3. P. douglassi is supported as being a valid species of Baiotomeus.
4. Neoplagiaulax fractus is recognized as Ptilodus, (as has been the case
for a while).
5. Three further Tiffanian species are recognized. Unfortunately, I don't know which.
That's a pity. Otherwise, I think the structure below was already in line with these
conclusions. If so, then please give the sources a round of applause.
The following is based upon my reading of Broom, 1914. It concerns a skull described as
P. gracilis in 1909. I'm presently treating P. gracilus as within the genus
Cymolomys, but I've no idea whether that should apply to this specimen. Apart from
stating it's in the collection of the United States National Museum, Washington and was
described by Gidley in 1909, I can't find any indication of its identity; eg. a catalogue
number. As it's my present understanding that C. gracilus is a Cretaceous multi,
and no Cretaceous multi skulls in this condition were available in 1909, I think I'll call
it P. gracilis here, in line with Broom. Enlightenment would be welcome. Incidentally,
it's labelled gracilis and not gracilus. (It's not my typo.)
Gidley's friend P. gracilis
According to Broom (p.121), Gidley described a reasonably complete skull of P. gracilis
in 1909. The animal was also kind enough to donate other bits of its body. With
characteristic generosity: "Gidley's description leaves little to be desired..."
I'll have to disagree on this point, as it leaves me desiring a copy. Still, Broom was
good enough to provide some guidance anyway, and he also includes some sketches from above
and below on page 122. I've dashed off a quick scribble myself:
'Ptilodus gracilus'.
From the occlusal perspective it's a very triangular skull,
and contrasts sharply with some multis such as Taeniolabis. What'd you mean, you
don't know what Taeniolabis looks like? Do you really think I've got nothing better
to do than draw poor sketches? Oh, OK, if I must:
Taeniolabis from
on high.
Anyway, returning to P. gracilis, to the fore the nasal
bones are large and the frontals merit the accolade
'moderately large'. The zygomatic arch of the cheek
area appears to be a partnership run by the front of the squamosal and the rear of the
maxilla, although it couldn't be ruled out that a small
jugal bone was between the duo (p.123). Crushing has reduced clarity.
Broom thought he could identify a cast of the
cochlear canal of the ear. In placentals and
marsupials this coils for 360° or more. It's not so
coiled in monotremes (less than 270°). The latter
appears to apply for this Ptilodus (if that's the correct genus).
With thanks to Benton, 1991b
I had to spend nearly two quid on this book, and that's far beyond my usual budget.
However, it does have a photo on page 38, and I'm holding it up to the monitor now.
It shows an unusually generous specimen from the Cruzy Mountain Basin of Montana.
The skull is rather smashed, but the main absentees with this P. individual
are the front legs. Most the rest of the body is there, and that includes clawed
toes and tail.
Donald Quarry, Montana
Remarks: According to Bloch J, Boyer D & Krause D (Society of Vertebrate Paleontology Abstracts, 2006,
p.43A9, this genus also occurs at Donald Quarry (Upper Paleocene), Montana. It's
one of at least three multis accused of having lived there during the Tiffanian, by
researchers from the Florida Museum of Natural History and Stony Brook University.
The mammalian fauna reportedly so far includes 30 species.
| Reassigned species: P. admiralis Hay, 1930 see P. montanus;
P. cochranensis Russell, 1929 see Anconodon
cochranensis; P. douglassi Simpson, 1835 see
Baiotomeus douglassi; P. ferronensis Gazin, 1941 see P.
mediaevus; P. formosus Gidley, 1909 see
Mesodma formosa; P. formosus Gidley, 1909 see
Mesodma formosa; P.? gidleyi Simpson, 1935 see
Anconodon gidleyi; P. gracilus Osborn, 1893
see Cimolomys gracilus; P.
plicatus Gidley, 1909 see P. mediaevus; P. primaevus Lamb, 1902
see Mesodma primaeva; P. serratus Gidley, 1909
see Cimolodon nitidus; ?P. sinclairi Simpson,
1935 see ?Liotomus sinclairi and
Parectypodus sinclairi; P. trouessarti and P.
trouessartianus Cope, 1882 see Parectypodus
trovessartianus | |
| Species: | Ptilodus mediaevus Cope ED, 1881 |
| Aka: | Chirox plicatus Cope, 1884; Ptilodus feronensis;
Ptilodus ferronensis Gazin CL, 1941; Ptilodus plicatus Gidley, 1909 |
| Place: | San Juan Basin, New Mexico & Utah &
Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: |
In a paper in 1887, Cope described Chirox as a marsupial. It
wasn’t. P. plicatus was synonymized with P. mediaevus by Granger &
Simpson, 1929. This same fate befell P. ferronensis according to Rigby, 1980. |
| References: | Cope (1881), Eocene Plagiaulacidae. The American Naturalist
15, p.921-922. |
| Gazin (1941), The mammalian faunas of the Paleocene of central
Utah, with notes on the geology. Proc. US Nat. Mus. 91, p.1-53, 29 figs., 3 pls.
|
| Species: | Ptilodus montanus Douglass E, 1908 |
| Aka: | P. admiralis Hay, 1930; P. gracillis Gidley JW, 1909 |
| Place: | Silberling Quarry, Montana & Blindman River, Alberta |
| Country: | USA & Canada |
| Age: | lower Tiffanian, Paleocene |
| Remarks: | This was apparently a biggy, 640g. "A
brain cast shows olfactory bulbs developed to a remarkable degree, indicating an excellent
sense of smell," (Burkitt, JH).
The Alberta material is mentioned by LeBlanc 2000, (p.60). A specimen known as AMNH 35490
works in the collection of the Smithsonian Institute.
Four partial lower jaws and other isolated teeth have been referred to this species, (Scott
2003, p.751). They come from the Who Nose? fauna of
Calgary. Based on a sample of six specimens, the length of the large (p4)
premolar averages out to 8mm, (Table 6, p.753). This is
fully in line with a large body size. With other multis from the same fauna, this
measurement fits between an approximate range of 2 to 5mm. |
| References: | Douglass (1908), Vertebrate fossils from the Fort Union beds.
Ann. Carnegie Museum, 5, p.11-26. |
| Gidley (1909), Notes on the fossil mammalian genus Ptilodon,
with descriptions of new species. Proc. US Nat. Museum XXXVI, p.611-626, 9 figs., pl.LXX.
|
| Species: | Ptilodus sinclairi Simpson GG, 1935 |
| Place: | Wheatland County, Montana |
| Country: | USA |
| Age: | Lower Paleocene |
| Remarks: | A further Yale resident, which has possibly been
reassigned. Parectypodus sinclairi? |
| Reference: | |
| Species: | Ptilodus wyomingensis Jepsen GL, 1940 |
| Place: | Rock Bench Quarry, Wyoming & North Dakota |
| Country: | USA |
| Age: | Middle Paleocene |
| Remarks: | The following is based upon my reading of
Szalay, 1965. It doesn't necessarily pertain precisely to this species. Rather, one of
the stars of the show is a juvenile P. cf. wyomingensis, and the cf. is one of
those Latin abbreviations, the longer version of which I've never stored in my memory; eg.
ie. It indicates the fossil's worth looking at with comparisons to that species, as it
seems to match at least closely.
The prelude
What's on offer here is a thrilling piece of action theatre. We've also got a second
young co-star; a juvenile Cimolodon. They've both been
rehearsing hard, and want to tell you something about their tooth replacement patterns. A
bit of help will be provided by Hahn & Hahn, 2000, as that contains some information on
the Upper Jurassic old days. Ladies and gentlemen, if you'd stop yapping about nothing in
particular, our show is about to begin. Please give these youngsters a rousing reception
as they toddle onto the stage. Clap and yell as loudly as you like, as research has
revealed that it can't possibly alarm them. They're totally dead in both ears. (Note:
they presumably had a pair each.)
It's kiddies' show time
On what I hope was a pleasant day in 1963, a party of jolly paleontologists wandered out
through the doors of the American Museum of Natural History, New York, in order to do a
spot of fossiling. I trust they took plenty of sandwiches, as they wandered halfway across
the country to southern Wyoming (p.1). Most the remains they extracted came out of Swain
Quarry in the Fort Union Formation, and are Middle Paleocene in age (approximately
Torrejonian, or 60 million years old for those not seeking too much precision). Lots of
these fossils had been dropped by careless multituberculate
mammals. For example, our junior Ptilodus had discarded part of its lower jaw, and
this piece of natural litter was particularly welcome. It had something new to say.
On toothy critters
Multis were mammals, and all existing toothed mammals,
which live long enough, will be supplied with two sets of teeth by Mother Nature. The milk
teeth get replaced once, but only once. This system of single replacement is termed
diphyodont, and it's the price that needs paying for
being provided with exceptionally complex and effective gnashers. Some of the teeth don't
get replaced at all. A placental mammal should never
develop secondary molars, and these are primary teeth. (
Marsupials are even stingier. They only replace their final premolars.) Using tricks,
such as delayed eruption, means molars can be discarded for
fresh substitutes in some cases, eg. at least some grass-munching mammals, but these
latecomers still aren't direct replacements, as they get anchored into different bits of
the jaw.
As this behaviour governs all living toothed mammals, it might be tempting to project it
back in time for all extinct forms as well. However, nothing is stable and our tooth
replacement system has been subjected to evolutionary tinkering. For instance, back in the
1960s, nobody had ever heard of ancient mammals replacing molars, but that would've been a
poor basis for concluding such behaviour had never occurred. It's now known that a Lower
Cretaceous mammal from Montana did this to some extent:
Gobiconodon ostromi. (The Gobi hasn't suddenly swept across eastern Asia and
the Pacific. Similar animals from Mongolia were described earlier, and G. ostromi
fitted into the genus.)
Despite a reasonably good supply of multi jaws, none had previously spoken much about their
tooth replacement behaviour. Clues were few. This bit of juvenile
dentary includes an incisor, which was getting ready to use its ejector seat, and there's
a new one determined to take over (p.2). Its ambitions were thwarted by a fatal
interruption.
Meanwhile, in Portugal
At about the same time as American paleontologists were raiding Swain Quarry, German
counterparts were busy at an Upper Jurassic coal seam in Iberia;
Guimarota.
With some years of inactivity aside, those excavations continued until 1982. The
endeavour was also richly rewarded with multis and other mammals; the most stunning
Jurassic haul nobody would've dared hope for. The tally of new multi species stands at
twenty. While five are based only on isolated teeth, the rest are represented by either
upper or lower jaws, and some overlap must be in play. In one instance, the upper and lower
were found in association, but the others can't yet be matched up.
Among this riot of new material were specimens providing fine evidence about replacement
patterns, although these were some of the most primitive multis and significant differences
could've developed during the 90 million year journey to Ptilodus.
One difference is obvious. Some of these early birds had five upper
premolars per side, whereas latter versions favoured four.
Another contrast is that none of the premolars were specialised for shearing food. They
were all involved in either clasping and/or grinding. The replacement reflects a sequence
known from non-mammalian cynodonts, in that it
alternated; first P1 then P3, 5, 2 and 4. Ptilodus may well have a more
derived scheme. It certainly did to some degree, as it had
one less upper premolar.
This interlude and update has been supported by Hahn & Hahn, 2000 (p.101).
Back to Szalay, 1965 page 3
The juvenile Ptilodus kindly donated part of its left lower
mandible, running from the two incisors (one
deciduous and one replacement) to just behind the remains
of the premolar p4. Also present is a useless looking p3. The crown of that is buried
beneath a front extension of its much, much, oh so much bigger colleague. I can think
of two possible uses for this runt; a bit of protection for the gum in front of p4, and a
front prop for the overhang.
Still, this study wasn't concerned with derogatory comments about the pathetic physique of
a puny premolar.
The frozen launch of a new incisor
The rudely interrupted action is located at the front of the fossil. Here can be seen the
root of a deciduous incisor (most of the crown is broken
off), and the 2 millimetre tip of an entirely unused replacement, which hoped to thrust its
way diagonally upwards. It's slanting at much the same angle as its doomed predecessor.
Concerning the remains of the original incisor (page 4): "The medial surface of the
incisor is wider than the superior one...", as shown by an illustration, and the
enamel is unevenly distributed. Assuming this applied for the whole crown, which is a
reasonable thing to do, then the pair of deciduous incisors could've worked as a piercing
device for foodstuffs with difficult to open packaging. Szalay suggests: "... resistant
or slippery coverings, or both."
The new incisor is sneakily growing right behind, and rudely shoving its predecessor aside.
Cimolodon sp.
Szalay had borrowed a partial right maxilla of a juvenile
multi from the Upper Cretaceous Hell Creek Formation, South Dakota. The referral to
Cimolodon is tentative (p.5). While both size and
morphology were in agreement on the subject, Cimolodon appeared to include hard to
differentiate members of a number of lineages.
The borrowed fossil came supplied with remains of the bony palate and three premolars, with
the firs (P1) being as wide as long (1.4mm). This tooth was newly erupted and the roots
were still ossifying (p.6). That's enough to determine its owner wasn't an adult. The
crown possessed a triangular arrangement of three cusps; one
buccal and two lingual. As the tooth behind is a milk
premolar and the third is the permanent P2, then replacement of the first premolar had
already occurred; ie. this is a P1 and not a dP1. (That fits in nicely with the
replacement pattern subsequently determined for the Guimarota multis.)
An interesting point concerning the P2 and its predecessor, dP2, is that the crowns differ
strongly. P2 is a tooth with three cusps, and bears more resemblance to the P1. If I'm
interpreting Figure 5 sensibly, dP2 is a longer tooth with a more complex crown. Replacement
postcanines in mammals are often simpler than the first teeth, and this reflects different
duties dictated by the effects of jaw growth. Regardless of the available length, the
bite power of jaws is always concentrated at the back; nearest the hinge. In a juvenile, a
premolar may be at a distance from the joint, which will later be equivalent to a molar
position. Consequently, milk premolars may be required to act as stand in molars. The
replacement tooth erupts further forwards from the joint, and this is simply because the
bone's had more time to grow.
Dental replacement
This specimen doesn't provide a great amount of information on the replacement sequence,
but it's better than nothing (p.7). The P1 is better developed than P2, and must've
appeared first. It presumably had an already ejected deciduous precursor, but it refused to
discuss the rest of the story. While the Guimarota multis provide some good suggestions,
they aren't necessarily all applicable.
Upper premolar functions
A curious sounding asymmetry exists between the numbers of upper and lower premolars. There
are two per side below and four above. As I've already mentioned the physical inadequacies
of the foremost lower, I'm not going to risk causing it further psychological pain by casting
more aspersions on its utter uselessness as a food processor. Even absurd runts don't
deserve having their inner feelings needlessly stamped upon, just because they're genuinely
pathetic.
Effectively, in all but basal multis, there was only one
lower premolar worthy of the name; a big, serrated blade
of a thing. In order for this to do its duty, it had to be accurately aligned with a tooth
above, as a single-bladed pair of scissors would get laughed at by sheets of paper. Its
partner in cutting was the P4.
That left three more upper premolars hanging around with little below to occlude with.
However, as multis keenly maintained these teeth, they were presumably useful. One good
possibility would have been for holding food items in place, and organising them for
dispatch to the rear (p.9).
In basal multis, such as many of the Guimarota gang, the premolars didn't have a shearing
function. As with the molars they were grinders. Cutting specialities arose later. This
supports the interpretation that Cimolodon and friends were descendants of an
animal, whose posterior upper premolars were involved in chewing, or so it seems to me.
This could help account for the retention of a fairly redundant style of crown; recycled
chewing teeth with cusps which no longer chewed (p.10). If they already worked as
efficient clamps, then there may have been little pressure for refinement. Don't try and
fix what ain't broke.
As a wise mechanic might confirm: inappropriate screwing around can have unwelcome
consequences. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Pro. Amer. Philos. Soc, 83, p.217-340, 21 figs., 5pls.
|
| Species: | Ptilodus nellieae Bell, 1941 (in ms) |
| Place: | Polecat Bench Formation, Montana |
| Country: | USA |
| Age: | Paleocene |
| Remarks: | I suspect this is defunct. Listed at Peabody, Yale. |
| Reference: | |
| Species: | Ptilodus fractus Dorr JA, 1952 |
| Aka: | Neoplagiaulax fractus Dorr JA, 1952 |
| Place: | Dell Creek, Wyoming |
| Country: | USA |
| Age: | Tiffanian, Paleocene |
| Remarks: | Further Yale specimens in the collection, under
the name of N. Body weight of about 85g.
I've also seen the citation as (Dorr, 1952) Krause, 1987a, and I'm not sure which is
correct. The formulation I'm following is in Scott et al, 2002 (p.694). |
| Reference: | Dorr (1952), Early Cenozoic stratigraphy and vertebrate
paleontology of the Hoback Basin, Wyoming. Bulletin of the Geological Society of America 63,
p.59-94. |
| Species: | Ptilodus kummae Krause DW, 1977 |
| Place: | Roche Percée, Saskatchewan &
Wyoming |
| Country: | Canada & USA |
| Age: | Tiffanian, Paleocene |
| Remarks: | Estimated weight, 120g. Presently attending
Alberta University. |
| Reference: | Krause (1977), Paleocene multituberculates (Mammalia) of the
Roche Percee Local Fauna, Ravenscrag Formation, Saskatchewan, Canada. Palaeontographica
Abt. A 186, p.1-36. |
| Species: | Ptilodus tsosiensis Sloan RE, 1981 |
| Place: | San Juan Basin, New Mexico, Montana, Wyoming, Utah & Rav W-1,
Saskatchewan |
| Country: | USA & Canada |
| Age: | Puercan, Lower Paleocene |
| Remarks: | |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates from
the San Juan Basin, New Mexico, p.127-160, in Lucas et al (eds), Advances in San Juan Basin
paleontology. University of New Mexico Press, Alberquerque. |
| Species: | Ptilodus gnomus Scott CS, Fox RC & Youzwyshyn GP,
2002 |
| Aka: | cf. Ectypodus hazeni (Jepsen, 1940), Gazin 1956a |
| Place: | Cochrane 2, Paskapoo Formation, Alberta &
Wyoming |
| Country: | Canada & USA |
| Age: | upper Torrejonian - lower Tiffanian, Paleocene |
| Remarks: | The following is based on my reading of Scott et
al 2002, (with more thanks to the kindly supplier).
Remains of this species include over 100 teeth, (upper and lower), and at least one
fragment of jaw. The dentition range between lengths
of less than two to greater than five mm. The fourth lower
premolar, p4, is about 51% shorter than the corresponding chopper in P. mediaevus;
28% less than P. kummae ; 15% below P. tsosiensis; and 5% smaller than for
P. fractus, which gives some idea of the relative sizes of the various critters.
(It's a strange-looking tooth with diagonal ridges and serrations, which vaguely reminds me
of an oyster shell, and it sits behind a much smaller peggy p3 and the spectacular tusked
incisor. I don't suppose multis found this odd.) There
are also differences in shape and the number of serrations.
"Although more similar in size to homologous teeth referable to P. tsosiensis
and P. fractus, the upper and lower ultimate premolars of this new species most
closely resemble those of P. mediaevus in overall morphology", (Scott et al 2002,
p.694).
A couple of isolated teeth which had been previously identified as perhaps belonging to
Ectypodus, have been now been placed within this taxon. All referred specimens are
students of the University of Alberta.
The authors mention there are three species of this genus known from the Alberta location,
two of which have yet to be described. This will be attended to by Krause DW, (p.691).
The species name is New Latin for 'dwarf', seeing as it's the smallest known member of the
genus. The paper is available on-line, (see Baiotomeus russelli for the link, above).
New specimens from a second locality, Who Nose?,
discussed by Scott, 2003 (p.750), have extended the geological range of this species. Its
first appearance in the fossil record is now somewhat earlier. |
| Reference: | Scott, Fox & Youzwyshyn (2002), New earliest Tiffanian
(late Paleocene) mammals from Cochrane 2, southwestern Alberta, Canada. Acta Palaeontologica
Polonica 47 (4), p.691-704. |
| Other reports:
Xxxxxxxxxxxxxx
Xxxxxxxxxxxxxx |
A. Neoplagiaulacidae & Neoliotomus B.
B. Ptilodontidae C. Cimolodontidae
| Taxon: Cimolodontidae Marsh, 1889
Reference: Marsh (1889), Discovery of Cretaceous Mammalia. Part II. American J. of Sci., 3, 38, p.81-92.
Small furry critters known mainly from teeth. Much multi-naming of these multis has gone on
over the years. Kielan-Jaworowska and Hurum (2001) recognize only three valid genera in
this family, along with a couple of question marks. They also place it within
Ptilodontoidea Sloan & Van Valen, 1965.
Genera: Allacodon (at least partly = Cimolodon),
Anconodon, Cimolodon, Cimolomys (at least
partly = Cimolodon), Ectopodon (= Anconodon), Ectypodus (at least partly =
Anconodon), Halodon (at least partly = Cimolodon),
Liotomus (partly = Anconodon / Parectypodus), Nanomyops
(= Cimolodon), Nanomys (= Cimolodon), Neoctenacodon
(= Liotomus), Ptlodus (partly = Cimolodon and Liotomus),
other reports
Time-Line:
Paleocene: Anconodon, Liotomus
Upper Cretaceous: Anconodon, Cimolodon |
| Genus: Anconodon Jepsen GL,
1940
Aka: Ectopodon Russell, 1967; Ectypodus (partly); Liotomus (partly);
Ptilodus (partly)
Remarks: According to Bloch J, Boyer D & Krause D (Society of Vertebrate Paleontology Abstracts, 2006,
p.43A9, this genus also occurs at Donald Quarry (Upper Paleocene), Montana. It's
one of at least three multis accused of having lived there during the Tiffanian, by
researchers from the Florida Museum of Natural History and Stony Brook University.
The mammalian fauna reportedly so far includes 30 species.
Reference: Jepsen (1940), Paleocene faunas of the Polecat Bench formation, Park County,
Wyoming. Pro. Amer. Philos. Soc, 83, p.217-340.
| Reassigned species: A. russelli (Simpson, 1935) see A.
cochcranensis | |
| Species: | Anconodon cochranensis (Russell, 1929) Van Valen & Sloan, 1966 |
| Aka: | A. russelli (Simpson, 1935) Jepsen, 1940; Ectopodon cochranensis Russel, 1967; Ectypodus cochranensis Simpson, 1937a; Ectypodus russelli Simpson, 1935d; Liotomus russelli; Ptilodus cochranensis Russell, 1929 |
| Place: | Alberta & Montana &
Wyoming |
| Country: | Canada & USA |
| Age: | upper Torrejonian - lower Tiffanian, Paleocene |
| Remarks: | "Descendant of A. gidleyi,"
(Burkitt JH). The holotype is in the University of Alberta collection. The Peabody
collection at Yale also includes material, as does the AMNH in New York. With those last
two collections, the species name russeli is also in use. Body mass is estimated at about
two standard mice, (55g). A. russelli is a synonym of A. cochranensis,
reportedly according to Hartmann (1986) and Sloan (1987).
Scott, 2003 (p.751) includes of new specimen referred to this species from the
Who Nose? locality, Calgary. It's a lower
premolar (p4), with a length of 4.7mm. It's smaller than
A. gidleyi, which Scott calls 'contemporaneous'. The Who Nose? fossil serves to push
the geological range of this species back somewhat. |
| References: | Russell (1929), Paleocene vertebrates from Alberta. American
Journal of Science, 17, p.162-178. |
| Jepsen (1940), Paleocene faunas of the Polecat Bench Formation,
Wyoming. Proceedings of the American Philosophical Society, 83, p.217-340. |
| Species: | Anconodon gidleyi (Simpson GG, 1935) Jepsen GL, 1940 |
| Aka: | A. gibleyi; Ptilodus? gidleyi Simpson, 1935d |
| Place: | Gidley Quarry, Montana & Wyoming & New Mexico & Alberta |
| Country: | USA & Canada |
| Age: | Torrejonian, Middle-Upper Paleocene |
| Remarks: | "This genus is a descendant of
Cimolodon nitidus," (Burkitt JH). One specimen is at the AMNH, New York,
whilst a couple are at Yale. |
| Reference: | Simpson (1935), New Paleocene mammals from the Fort Union of Montana. Proc. US Nation. Museum 83, p.221-244. |
| Species: | Anconodon lewisi Sloan RE, 1987 |
| Place: | Keefer Hill &
The Breaks, Wyoming
& Douglass Quarry, Montana |
| Country: | USA |
| Age: | Middle-Upper Paleocene |
| Remarks: | Type fossil from Wyoming. |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammal ages,
biozones, magetozones, rates of sedimentation, and evolution, in Fassett JE &
Rigby JK (eds.), The Cretaceous-Tertiary boundary in the San Juan and Raton Basins, New
Mexico and Colorado, Geological Society of America Special Paper 209, p.165-200. |
| Genus: Cimolodon Marsh OC,
1889
Aka: Allacodon (partly); Cimolomys (partly); Halodon Marsh, 1889;
Nanomys ('small mouse') Marsh, 1889; Nanomyops Marsh, 1892; Ptilodus
(partly)
Remarks: The following is based mainly upon my reading of Simpson, 1927.
Simpson viewed this genus as a useful hodgepodge for broadly similar fossils, and stated
it may contain material from separate genera of small multis. He had four specimens from
Montana in 1927, and didn't refer any to a particular species. Remains of a lower
molar (m2) showed the tooth was 2.7mm in length and 2.2 wide.
It had four buccal cusps and two
lingual ones. There was also a lower premolar with 13
serrations; an upper molar (cusp formula 7, 9, 7 from buccal to lingual rows) and a further
lower one (p.5).
While an unnatural taxon such as Cimolodon isn't
satisfactory, coming up with a better arrangement wasn't possible with the available
fossils. He specified he was using the genus in a 'broad sense'. Consequently, anywhere
between none to all of those specimens could belong to this critter.
In addition
Whilst some Cimolomys material has indeed been referred to Cimolodon, that doesn't necessarily mean that the whole genus, or particular species has. It could well be that one-time Cimolodon fossils have subsequently also been referred to Cimolomys as well. If you find this somewhat confusing, so do I.
"Cimolodon seems to be more closely related to the Paracimexomys group
than are other ptilodontoideans," (Kielan-Jaworowska & Hurum, 2001, p.404). Odd
as it may sound, the placement of this genus within Cimolodontidae is tentative. Its
tooth enamel is gigantoprismatic, (organized into large prisms), whilst its possible
relatives favour a microprismatic style (small prisms), (p.418 of the same paper).
A juvenile Cimolodon is involved in discussions on tooth replacement, and this is
presently housed in the entry for Ptilodus wyomingensis.
That's located a bit higher up on this page.
| Reassigned species: C. nitidus Russell, 1936 see (partly)
Essonodon browni and
Mesodma thompsoni | |
| Species: | Cimolodon nitidus Marsh OC, 1889 |
| Aka: | Allacodon lentus Marsh, 1889; Allacodon rarus Marsh,
1892; Cimolomys bellus Marsh, 1889; Cimolomys digona Marsh, 1899;
Cimolomys gracilis Marsh, 1889; Cimolomys minutus; Cimolomys nitidus;
Halodon serratus Marsh, 1889; Nanomyops minitus Marsh, 1892;
Nanomys minitus Marsh 1889; Ptilodus serratus Gidley, 1909 |
| Place: | Wyoming, Alaska?,
Hell Creek Montana,
North Dakota, South Dakota, Utah & Alberta,
Saskatchewan |
| Country: | USA & Canada |
| Age: | Campanian - Maastrichtian, Upper Cretaceous |
| Remarks: | The following few lines are based upon my
reading of Lofgren, 1995. Thanks are due to the Birthday Bunny.
Some specimens from the upper Hell Creek Formation and Saskatchewan's Ravenscrag Formation
may date from the Paleocene (p.78). However, Lofgren raises doubts about that. They
could simply have been reworked by mischievous watercourses muddling things up. An M1
upper molar from the McGuire Creek localities (Hell Creek Fm.)
is in line with an earlier description by Clemens. That was the only specimen identified
from there.
Size
The M1 just mentioned is 4.51mm long, 2.57 wide and has a cusp formula of 5:7:5
(buccal to lingual).
Holotype
YPM 11776 is an upper molar studying at Yale University.
Additional notes
Osborn, 1893 (p.315) states that Halodon
serratus was established on the basis of lower premolars
(p4). He concluded this was synonymous with Ptilodus; a genus now restricted to
fossils from the Paleocene.
Nanomys minutus was based on an m2 lower molar (p.316). Cimolomys digona
consisted of upper molars (M1). The crowns had three rows of cusps, but the internal row
didn't run along the entire length (p.317). Halodon serratus was based on lower
incisors (p.318).
A suggested weight for this species is about
230g, which would equate to a well-fed common
rat. Simpson
referred this to C. gracilis in 1929. Subsequently, it's been reallocated to
C. nitidus by various authors, apparently beginning with Clemens in 1963.
Up North
The Alaskan record concerns a species which is at least similar to C. nitidus,
although it could be a close relative. This was found in the Prince Creek Formation.
Presently, this is the most northerly known multi outpost. (Thanks are due to Ken
Carpenter for posting the information to the Dinosaur Mailing List on 11.11.2005. His
informant was Greg Wilson of the Denver Museum of Nature and Science.)
Holotype
The holotype resides at the Peabody Museum, Yale. It's affectionately known as YPM 11776,
and is a lower left molar (m1). This was recovered from the
Lance Formation of Wyoming, (Hunter & Archibald 2002, p.194). The chronological range
might extend into the Paleocene in Saskatchewan, (Ravenscrag Formation). However, as
mentioned above, that could be due to reworking. |
| References: | Marsh (1889,) Discovery of Cretaceous Mammalia part 1,
American Journal of Science, 3, p.81-92. |
| Simpson (1929), American Mesozoic Mammalia. Mem. Peabody Mus.
Nat. Hist. iii (i), p.1-235. |
| Species: | Cimolodon parvus Marsh OC, 1892 |
| Place: | Lance Formation, Wyoming |
| Country: | USA |
| Age: | Upper Cretaceous |
| Remarks: | Some material at Yale. At least in part, the
following seems to be the case: C. parvus was referred to Cimolomys parvus.
This became (sensu Simpson) Cimolomys gracilis. Presently, it appears to be
Mesodma sp., courtesy of Clemens (1963). |
| References: | Marsh (1892), Discovery of Cretaceous Mammalia. Pt. III. Am. J. Sci. (3) xliii, p.249-262. |
| Simpson (1929), American Mesozoic Mammalia. Mem. Peabody Mus. Nat. Hist. iii (i), p.1-235. |
| Clemens (1963), Fossil mammals of the type Lance formation Wyoming. Part I. Introduction and Multituberculata. Univ. Calif. Pub;. Geol. Sci. 48, p.1-105. |
| Species: | Cimolodon electus Fox RC, 1971 |
| Place: | Upper Milk River Formation, Alberta & Texas, New Mexico,
Utah |
| Country: | Canada & USA |
| Age: | Campanian, Upper Cretaceous |
| Remarks: | Type fossil at Alberta. Possible finds have been
reported in New Mexico, and are mentioned in Foote et al, 1999. Weight guestimate = 195g,
which is similar to a common
rat. |
| Reference: | Fox (1971), Early Campanian multituberculates ( Mammalia: Allotheria) from the
upper Milk River Formation, Alberta. Canadian Journal of Earth Sciences, 8 (8), p.916-938. |
| Species: | Cimolodon similis Fox RC, 1971 |
| Aka: | Cimolodon similus |
| Place: | Utah |
| Country: | USA |
| Age: | Campanian, Upper Cretaceous |
| Remarks: | Holotype also in Alberta University. A body
weight of about 5 mice, 125g. |
| Reference: | Fox (1971), Early Campanian multituberculates ( Mammalia: Allotheria) from the
upper Milk River Formation, Alberta. Canadian Journal of Earth Sciences, 8 (8), p.916-938. |
| Species: | Cimolodon wardi Eaton JG, 2006 |
| Place: | Cedar Canyon, Utah |
| Country: | USA |
| Age: | Upper Cretaceous |
| Remarks: | Thanks are due to Dino Hunter for uploading the
citation. Should anybody have a spare copy of the paper, then please feel invited to forward
it. |
| Reference: | Eaton (2006), Late Cretaceous mammals from Cedar Canyon,
Southwestern Utah, (In) Late Cretaceous Vertebrates from the Western Interior, Lucas SG &
Sullivan RM (Eds.), New Mexico Museum of Natural History & Science, Bulletin 35,
p.373-402. |
| Species: | Cimolodon cf. similis |
| Place: | Utah & Texas |
| Country: | USA |
| Age: | Maastrichtian, Upper Cretaceous |
| Remarks: | |
| Reference: | |
| Species: | Cimolodon foxi |
| Place: | Straight Cliffs Formation, Utah |
| Country: | USA |
| Age: | Santonian - Campanian, Upper Cretaceous |
| Remarks: | This is mentioned in an abstract by Eaton JG,
2005 (see link). It's possible that other authors use different nomenclature, as I've not
come across the species previously. Whatever the original material was, it was aged as
Judithian. |
| Reference: | |
| Genus: Liotomus Cope ED,
1884
Aka: Neoctenacodon Lemoine, 1891; Neoplagiaulax (partly); Ptilodus
(partly)
Remarks: This genus is sometimes placed within Eucosmodontidae Jepsen, 1940.
Reference: Cope (1884), The Tertiary Marsupialia. American Naturalist, 18, p.686-697.
| Reassigned species: L. russelli seeAnconodon
cochranensis; L. vanvaleni seeParectypodus
vanvaleni | |
| Species: | Liotomus marshi (Lemoine, 1882) Cope ED, 1884 |
| Aka: | Neoctenacodon marshi; Neoplagiaulax marshi |
| Place: | Cernay |
| Country: | France |
| Age: | Upper Paleocene |
| Remarks: | Descendant of Anconodon gidleyi,
(Burkitt JH). Specimens at the AMNH, New York. Given the level of hatred which Cope felt
towards Marsh OC in 1884, I wonder why he chose this species name. Compare it to
Copeanus Marsh, (with thanks to Curiosities of Biological Nomenclature, by Mark Isaak).
It seems that Cope didn't name the species. This appears to have Lemoine in 1882. It was
subsequently reassigned to this genus. (Thanks to Vince Ward). |
| Reference: | |
| Species: | ?Liotomus sinclairi (Simpson GG, 1935), Vianey-Liaud M,
1986 |
| Aka: | Ptilodus sinclairi Simpson GG, 1935 |
| Place: | Montana and
Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | I wonder if this is Parectypodus
sinclairi in disguise. |
| References: | Simpson (1935), New Paleocene mammals from the Fort Union of
Montana, US National Museum Proceedings, vol83, p.221-244. |
| Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains, Palaeontographica Abteilung A
Paläozoologie-Stratigraphie, vol 191, p.85-171. |
| Other reports:
The North Pacific Coastal Region
Reference: Abel O (1922), Desmostylus, ein mariner Multituberculate aus dem Miozän der
nordpazifischen Küsten region. Acta Zool. III, p.361-394, pls.i-iii, 5 text-figs.
This seems to be of purely curiosity interest, if that. Desmostylus is some kind of
extinct seacow thing. Apparently, Hr Abel interpreted it as being an ocean going multi.
He must have had his reasons. |
| Help:
Should anybody have any further information, I'd be pleased to hear of it.
Regarding references and Bibliography:
I haven't and can't verify all the references, so beware. Traditional papers used in
constructing this page are in the bibliography. If you feel these are too few, then send
some more.
Trevor Dykes, December 2001. Latest update: 14.12.2009
Ktdykes@arcor.de |
| With further thanks due to:
John H Burkitt, Mammals, A World Listing of Living and Extinct Species
http://cougarhillweb.org/mammals.pdf
Martin Jehle, Paleocene mammals of the world, Class Mammalia
http://www.paleocene-mammals.de/pal1.htm
The Prehistoric Data Files
http://www.angellis.net/Web/PDfiles/marsups.pdf
Dr John Alroy, North American Fossil Mammal Systematics Database
http://www.nceas.ucsb.edu/~alroy/nafmsd.html
The source of a great deal of the above information; many locations, authors, chronology
and weight guestimates.
BIOSIS, The Index to Organism Names
http://www.biosis.org.uk/triton/indexfm.htm
The Society of Vertebrate Paleontology BFV Online, (John Damuth)
http://www.bfvol.org/
The Peabody On-line VP Catalogue
http://george.peabody.yale.edu/vp/
Jacques LeBlanc for providing the correct link.
The exciting animations have come courtesy of
HitBox Central,
Animation Library and
best animations.com. |
Bibliography:
Benton MJ (1990b), The Rise of the Mammals. Eagle Editions, (printed 1998), ISBN
1-902328-18-3.
Broom R (1914), On the structure and affinities of Multituberculata, Bulletin of the
American Museum of Natural History, 33(8), p.115-134.
Cox B, Dixon D, Gardiner B & Savage RJG (1989), Dinosaurier und andere Tiere der
Vorzeit, Mosaik Verlag (Sonderausgabe für Gondrom Verlag, 1994), ISBN 3 8112 1138 2
Delsate D (2000), Presence d'un Multituberculate de Petite Taille a la
transition Paleocene-Eocene de Dormaal (MP7, Belgique), Oryctos, 3, p.61-69.
Foote M, Hunter JP, Janis CM & Sepkoski JJ (1999), (Supplementary material for)
Evolutionary and preservational constraints on origins of biologic groups: divergence times
of eutherian mammals, Science 283.
Fox RC (1968), Studies of Late Cretaceous Vertebrates. II. Generic diversity
among multituberculates, Systematic Zoology, 17(3), p.339-342.
Fox RC (2002), The oldest Cenozoic mammal?, Journal of Vertebrate Paleontology,
22(2), p.456-459.
Granger WD & Simpson GG (1928), Multituberculates in the Wasatch Formation,
American Museum Novitates, 312, p.1-4.
Hahn G & Hahn R (2000), Multituberculates from the Guimarota mine, p.97-107 in
Martin T & Krebs B (eds), Guimarota - A Jurassic Ecosystem, Verlag Dr Friedrich Pfeil,
München.
Higgins P (2003a), A New Species of Paleocene Multituberculate (Mammalia:
Allotheria) from the Hanna Basin, South-Central Wyoming. Journal of Vertebrate
Paleontology, 23 (2), p.468-470.
Higgins P (2003), A Wyoming succession of Paleocene mammal-bearing localities
bracketing the boundary between the Torrejonian and Tiffanian North American Land Mammal
"Ages", Rocky Mountain Geology, 38 (2), p.247-280.
Hunter JP & Archibald JD (2002), Mammals from the end of the age of the
dinosaurs in North Dakota and southeastern Montana, with a reappraisal of geographic
differentiation among Lancian mammals, in Hartman JH, Johnson KR & Nichols DJ
(eds.), The Hell Creek Formation and the Cretaceous Tertiary boundary in the northern
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multituberculate mammals, Palaeontology, Vol 44 (3), p.389-429.
Krause DW (1987), Sytematic revision ot the genus Prochetodon
(Ptilodontidae, Multituberculata) from the Late Paleocene and Early Eocene of Western
North America, Contributions from the Museum of Paleontology, The University of
Michigan, 27(8), p.221-236.
Kühne WG (1969), A multituberculate from the Eocene of the London Basin,
Proceedings of the Geol. Society of London, 1658, p.199-202.
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notes on adjacent areas of British Columbia. On-line edition available at:
http://www.diplomatsinternational.com/PaleoPublications.htm.
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