| MESOZOIC MAMMALS; Plagiaulacidae, Albionbaataridae, Eobaataridae & Arginbaataridae, an internet directory: |
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.
| These animals were members of 'Plagiaulacida' Simpson, 1925, (nomen correctum McKenna, 1971 ex Plagiaulacoidea), a basal grouping of multituberculates. The origins of multis may lie amongst the haramiyidans, (or more likely not!), whilst their descendents survived until about 40 million years ago. Based on the distinctive teeth, they’re often regarded as herbivores, at least more or less. However, in the modern world, there are a number of 'herbivores' which eat meat, (ham is an effective bait for a mouse trap), and some 'carnivores' who can hardly stand the stuff; eg. giant pandas. Where known, "the anatomy of the pelvis suggests that multituberculates did not lay eggs like monotremes but gave birth to very small, immature young like marsupials," (quotation from Multituberculates: Heyday of the longest lived mammalian order. This essay, by Martin Jehle provides an excellent and accessible overview of the order). |
| Links: Mikko Haaramo's Allotheria A great deal of care goes into the construction of these cladogrammes. It’s not just a case of listing information. There’s also the little matter of keeping up with the current understanding of relationships, across a startling range of animal groups.
Mikko Haaramo's Plagiaulacoidea Mikko Haaramo's Plagiaulacoidea
Mammalia, by ? http://epp.eps.nagoya-u.ac.jp/~seicoro/bio/mammalia.html This is a new cladogramme in Japanese. This work’s not only very impressive, it’s also a HUGE file. You may well have time to make a cup of tea as it loads. If a very large, Japanese cladogramme doesn’t sound appealing, then proceed to the next link.
John H Burkitt, Mammals, A World Listing of Living and Extinct Species http://cougarhillweb.org/mammals.pdf This file’s also enormous. Dipping into the details strewn throughout this encyclopedic document, enhances the sense of wonder at the effort that went into it.
T Mike Keesey, The Dinosauricon, Ages of the Mesozoic http://www.dinosauricon.com/times/index.html This page saves memory capacity.
Martin Jehle's Paleocene mammals of the world, Class Mammalia http://www.paleocene-mammals.de/pal1.htm A welcome guide through the confusing maze of multi-named multis. |
A. Plagiaulacidae B Albionbaataridae C. Eobaataridae & Arginbaataridae
| A. PLAGIAULACIDAE |
| Taxon: Plagiaulacidae Gill TN, 1872 Bolodontidae Osborn HF, 1887 Remarks: According to Kielan-Jaworowska and Hurum (2001) Palaeontology 44, Bolodontidae is a synonym.
References: Gill (1872), Arrangement of the families of mammals. With analytical tables.
Smithsonian Miscellaneous Collections, 230, p.1-98.
Genera: Bolodon, ‘Ctenacodon’, Iberica, Parabolodon, Plagiaulax, Plioprion(=Bolodon), other reports
Time-Line: Lower Cretaceous: Bolodon, Iberica, Plagiaulax Upper Jurassic: ‘Ctenacodon’ |
| Genus: Bolodon Owen R, 1871 Aka: Plioprion
Remarks: Kielan-Jaworowska & Ensom, 1992 provides a dental formula (per side) for the
genus: uppers: 3 incisors, no
canine, 5 premolars, 2
molars; lowers: 1, 0, 4 and 2 respectively (p.109). This is a small plagiaulacid.
Distinguishments from Plagiaulax include a proportionately
smaller lower incisor and one more lower premolar. The p4 has less cusps on the
buccal side. That also applies for 'B.' falconeri,
which isn't part of the genus. 'B.' elongatus is another species in need of
reassignment. Reassigned species: B. elongatus Simpson, 1928 see
Parabolodon elongatus | |
| Link: Dr Ian West, Purbeck Type-Section, Durlston Bay, Swanage http://www.soton.ac.uk/~imw/durlmid.htm Another part of the fine project on the geology and paleontology of the Purbeck coast, UK. Plioprion has also been reported from this location, though it's now generally regarded as a synonym of Bolodon. |
| Species: | Bolodon crassidens Owen R, 1871 |
| Place: | Durlston Bay & Galve? |
| Country: | England & Spain? |
| Age: | Lower Cretaceous |
| Remarks: | Galve is mentioned by John H Burkitt. I haven't as yet found any confirmation for this. |
| Reference: | Owen, (1871), Monograph on the fossil Mammalia of the Mesozoic formations. Palaeontological Society Monograph, 24, p.1-115. |
| Species: | Bolodon minor (Falconer H, 1857) |
| Aka: | Plagiaulax minor Falconer H, 1857; Plioprion minor |
| Place: | Purbeck Limestone Group, Dorset |
| Country: | England |
| Age: | Lower Cretaceous |
| Remarks: | Kielan-Jaworowska & Ensom, 1992 provides
some information on the species. Falconer established the species within the genus of Plagiaulax, and the type fossil was subsequently referred to Plioprion by Hahn & Hahn in 1983 (p.118). That taxon was based on lower jaw remains, and these appear to belong to Bolodon. In keeping with its name, this species is relatively small. The p4 premolar has its serrations spaced more closely together than for B. osborni. This tooth also has a number of buccal cusps (possibly four), whereas its larger sister gets by with just one. Premolars p2 and 3 are morphologically similar. Several upper teeth from Sunnydown Farm may also belong to the species, as they're the right sort of size and build. Their referral is tentative pending further information. Holotype BMNH 47729 is a resident of the Natural History Museum, London. It's a right lower mandible with postcanine teeth. When found, all premolars and molars were present, but the m2 was lost at some stage. Additional notes B. minor is included in a table in Carpenter, 1998 (p.398), so the species appears to be valid. Its teeth are considerably smaller than is the case for its sister, B. osborni. The lengths given are for lowers. Premolars: p2 0.8mm, p3 1.0mm, p4 2.0mm. molars: m1 1.1mm. Plioprion Cope, 1884 is synonymous with Bolodon. |
| Reference: | Falconer (1857), Description of two species of fossil mammalian genus Plagiaulax from Purbeck, Quarterly Journal of the Geological Society of London, 13, p.261-282. |
| Species: | Bolodon osborni Simpson GG, 1928 |
| Aka: | Ctenacodon ?minor Simpson, 1928 |
| Place: | Purbeck Limestone Group, Dorset |
| Country: | England |
| Age: | Berriasian, Lower Cretaceous |
| Remarks: | The following is based upon my reading of
Kielan-Jaworowska & Ensom, 1992. As with B. minor, the lower p4 premolar is equipped with a blade containing six or seven serrations (p.110). This tooth is larger for B. osborni, there's only one buccal cusp, and ridges associated with the serrations are more widely spaced. Furthermore, the p3 is proportionately larger in comparison with the p4. B. osborni is smaller than B. crassidens, and the upper P4 premolar has a middle cusp row with a trio of large cusps (p.112), with a small cuspule to the front. There are also cuspules on the buccal side of the crown. The other species has two large cusps in the central row, and a cingulum to the front on the buccal side. Skull The length of the preserved jaw suggests a large mouse-sized animal with a three centimetre long skull. Lower incisor No specimen is yet available. Lower premolars There are four per side. Information on p1 is limited to a glimpse of the lingual side in one jaw. The p2 has three serrations, but one is weak. The buccal side has a pair of ridges, with a trio found on the lingual side. Premolar number 3 is larger. This tooth has four serrations and all but the first are associated with ridges. The p4 increases in size again. It nearly measures the same as its height (which is 2.3mm. The lengths are below, and they come from a paper by Carpenter. Both sources agree on them.) There are six serrations and ridges run from all but the first. Lower molars The m1 has a vaguely rectangular outline from the occlusal perspective, and a cusp formula of 2:2. However, the lingual side is a bit shorter than the buccal. The width amounts to 1.2mm. Of the two roots, the rear one is the largest. Both lingual cusps are crescentric and the foremost has a very small cuspule in front of it. Before the first buccal cusp is a raised cingulum. Both buccal cusps are conical. The second molar is somewhat larger, which is in contrast to later multis. Its length (not given by Carpenter) and width are 1.6mm and 1.3 respectively. The outline is more oval in this case, and the lingual row has two cusps with a wide groove between them. The buccal side of the crown features and ridge rather than distinct cusps, and this has suffered from wear at the front. Upper incisors There were three per side, but only part of an I2 is known. It was small. Upper premolars P1, 4 and 5 are preserved with the type fossil. P3's also present, but the following tooth blocks the view. Three isolated specimens are probable either P2s or 3s. These are double-rooted, and correspond with the holotype P3 in terms of size and morphology (p.114). They show the presence of a cingulum at the rear of the crown. In contrast to the P1, they lack a cingulum at the front, and are also smaller. Upper molars The M2 crown is longer on the lingual side than on the labial. Its buccal row contains two cusps, while the lingual has three. Holotypes The type fossil, BMNH 47735A, is a right maxilla with the postcanine dentition (excepting for P2). The type of C. cf. minor is BMNH 48399. This is a right lower jaw with premolars. Seven isolated teeth were subsequently found in the same sample of matrix from Sunnydown Farm, and these probably come from the same individual. Additional notes Carpenter, 1988 (p.398) supplies lower lengths as follows: premolars p2 1.7mm, p3 2.1mm, p4 2.4-2.7mm; molars m1 1.4mm. A tooth features on plate 2 of Kielan-Jaworowska & Hurum (2001). |
| Reference: | Simpson (1928), A catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum. Brit. Mus. (Nat. Hist.), London, p1-215. |
| Link: Palaeontology, 35 http://palaeontology.palass-pubs.org/pdf/Vol%2035/Pages%2095-126.pdf Kielan-Jaworowska & Ensom, 1992 is presently freely accessible in pdf format. |
| Species: | 'Bolodon' falconeri (Owen R, 1871) |
| Aka: | Plioprion falconeri Owen, 1871 |
| Place: | Purbeck Limestone Group, Dorset |
| Country: | England |
| Age: | Berriasian, Lower Cretaceous |
| Remarks: | Update It's possible this species could now be involved with Parabolodon, but I don't know. 'Bolodon' falconeri contrasts with Bolodon too much to qualify for the genus. The front upper premolars (P1-P3) lack prominant cingula at the back, and P1 is close in size with P2 instead of being clearly larger. The lower p4 has more buccal cusps (Kielan-Jaworowska & Ensom, 1992, p.109-110.) |
| Reference: | Owen, (1871), Monograph on the fossil Mammalia of the Mesozoic formations. Palaeontological Society Monograph, 24, p.1-115. |
| Species: | Bolodon sp. |
| Aka: | Plioprion sp. |
| Continent: | North America? |
| Age: | Upper Jurassic |
| Remarks: |
If this is accurate, Plioprion-Bolodon would be one of a number of
mammals recorded from both the USA and Dorset. (There’s
also a mini-dinosaur, Echinodon). In the other such cases, the American material is
from the Upper Jurassic Morrison Formation of Wyoming. However, I've yet to find any
confirmation for this entry. The Purbeck Limestone Group, UK, is now best interpreted as earliest Lower Cretaceous. Previously, it was thought that the Jurassic-Cret, (J-K), border ran through the middle of it. Contrastingly, the Purbeckian strata of Wyoming is held to be late Upper Jurassic. From a paleobook-keeping perspective, this is somewhat untidy. Such is life. Compared to the K-T border, the J-K is much fuzzier. Judging by the recorded fossils, the two sites were home to broadly similar mammal populations, at approximately the same time. |
| Reference: |
| Genus: ‘Ctenacodon’ 'comb tooth' Remarks: Although originally assigned to Ctenacodon: Allodontidae, this species has raised objections and demanded inclusion here. Specialists seem sympathetic to its case. |
| Species: | ‘Ctenacodon’ brentbaatar Bakker RT, 1998 |
| Place: | Morrison Formation, Wyoming |
| Country: | USA |
| Age: | Upper Jurassic |
| Remarks: | Update:
2004 saw the establishment of a taxon called Morrisonodon
brentbaatar. As Bakker's friend has the same specific name, comes from the
same time and place and was due for 'redevelopment', it would be extremely odd
indeed if this were not based on the same material. Confirmation would be welcome.
Meanwhile, from a sense of Über-caution, I'll let this entry remain until
certainty allows its final demolition. I'm 99.99% sure this fossil has been
assigned to that genus within Allodontidae. This was based on a well preserved upper tooth, (1mm long). The species name honours the Wyoming paleontologist, Brent Breithaupt. Baatar, ‘hero’, is apparently a reference to the heroics involved in surviving, whilst being very small and surrounded by dinosaurs. |
| Reference: | Bakker (1998) Dinosaur mid-life crisis: the Jurassic-Cretaceous transition in Wyoming and Colorado. in Lucas, Kirkland & Estep (eds.), Lower and Middle Cretaceous terrestrial ecosystems, New Mexico Museum of Nat Hist and Sci, Bulletin 14, p.67-77. |
| Link: Prehistoric Mammal Named in Honor of UW Paleontologist http://www.uwyo.edu/geomuseum/Baatar.htm A report from the University of Wyoming. If you want to try this sort of thing at home, the discovery involved a two ton block of rock, a kitchen table and eight years gentle tapping. I like the sketch. |
| Genus: Iberica Badiola A, Canudo JI &
Cuenca-Bescos, 2011 'for Iberia' Remarks: This genus is based upon isolated, upper, anterior premolars, and some other material has been tentatively assigned to it; to whit, a lower p4 premolar and two M2 molars. It's been referred to either this family of Palgiaulacidae or perhaps Eobaataridae. My cursory reading of the paper made the former sound more likely. However, further evidence would help clarify the matter. |
| Species: | Iberica hahni Badiola et al, 2011 |
| Place: | Galve, Teruel |
| Country: | Spain |
| Age: | upper Hauterivian-lower Barremian, Lower Cretaceous |
| Remarks: | Holotype. FCPT (CAN 1/936) is a left upper premolar from a locality called La Cantalera, and it's now held prisoner in the dungeons of the Fundacion Conjunto Paleontologico de Teruel-Deinpolis. The specific name honours both Gerhard and Renate Hahn for their efforts with taming Iberian Lower Cretaceous multis. As it honours both a man and a woman, I can't help but think the specific name needed emending before publication! I'm no lover of Latin grammar but the ending "i" is masculine. Frau Hahn isn't. Shouldn't the ending be -orum? |
| Reference: | Badiola et al (2011), A systematic reassessent of Early Cretaceous multituberculates from Galve (Teruel, Spain), Cretaceous Research, 32, p.45-57. |
| Genus: Parabolodon
Hahn & Hahn, 2004 'Beside Bolodon' Aka: Bolodon (partly)
Remarks: Two species assigned to Bolodon had previously been chastized for being in
the wrong genus, and at least one of those has now been transferred here. A second, "B.
falconeri" may also have been, but I have no information available on that as yet. |
| Species: | Parabolodon elongatus (Simpson GG, 1928) Hahn & Hahn, 2004 |
| Aka: | Bolodon elongatus Simpson, 1928 |
| Place: | Purbeck Limestone Group, Dorset |
| Country: | England |
| Age: | Berriasian, Lower Cretaceous |
| Remarks: | After a wait of seven years, I've finally got hold of a
paper that mentions the specific name of this multi and the relevant citations! Badiola et al
(2011) reports it as having upper front premolars with three cusps (p.48). Additional notes This species was originally assigned to Bolodon but: "?new genus to be erected for 'Bolodon' elongatus," (Kielan-Jaworowska & Hurum, 2001, p.414). Kielan-Jaworowska & Ensom, 1992 (p.122) states that the upper premolars, P1-P3, are distinct from the corresponding teeth of other species in several ways. They have a well-developed cingulum at the back, and the third premolar is smaller than the other two. It's also a relatively long tooth. |
| Referencse: | Simpson (1928), A Catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum, London, British Museum. |
| Hahn G & Hahn R (2004), The dentition of the Plagiaulacida (Multituberculata, Late Jurassic to Early Cretaceous), Geologica et Palaeontologica, 38, p.119-159. |
| Genus: Plagiaulax
Falconer H, 1857 Remarks: According to John H Burkitt, this genus was an insectivore. Generally, multis are regarded as omnivores to herbivores. Why he states that is something I don't know but, as far as I'm aware, that was Falconer's view in 1857. That's something I haven't personally seen.
Reassigned species: P. eocaenus see
Neoplagiaulax eocaenus | |
| Link: The Library of the University of Cambridge, the correspondence of Charles Darwin http://www.lib.cam.ac.uk/Departments/Darwin/calendar/all_cal.html
WARNING: This file is very large and needs plenty of time to load. Summaries
of Darwin’s post; about 14,000 items. In a letter to Hugh Falconer, shortly after the
publication of Plagiaulax, he suggested that Richard Owen would probably designate
all Purbeck mammals as marsupials, which is what
happened, (No. 3791, 7.3.1857). Falconer (and most other researchers for the next fifty
years) saw multis as probably being marsupials and I'm grateful to Broom, 1914 for making
that clear. 1,200 words by Self MY (ie. me). |
| Species: | Plagiaulax becklesii Falconer H, 1857 |
| Place: | Purbeck Limestone Group, Dorset |
| Country: | England |
| Age: | Lower Cretaceous |
| Remarks: | Some information's included in page 35 of
Hahn, 1971. At that time only a single specimen had ever been found, and perhaps
that's still the case. It's a lower jaw with a dental formula of: 1
incisor, 0 canine, 3
premolars and 2 molars. Earlier relatives had favoured four premolars, but this
rebel couldn't be bothered to grow the first of those. The second is retained but
as a modest remnant, and it took no part in the shearing duties of the dentition.
Five serrations adorn the crown of p3 whereas its larger comrade, p4, had been
allocated eight. The first molar had two cusps in its
buccal row and three in the lingual one. Quite
what the m2 was up to is unclear as crown details are obscurred by wear. Measure for measure The list of lengths is from Carpenter, 1998, (p.398). Premolars: p2 0.6-0.8mm, p3 1.5-1.7mm, p4 3.3mm. Molars: m1 1.8mm. For its time, this was one of the larger multis around. The range of premolar lengths could perhaps result from further specimens then being available. I can't think of a better explanation, but perhaps I'm not imaginative enough |
| Reference: | Falconer (1857), Description of two species of the fossil genus Plagiaulax from Purbeck, Quart. J. Geol. Soc. of London 13 p.261-282. |
| Links: Dr Ian West, Jaws and Teeth from Beckles’ Mammal Pit http://www.soton.ac.uk/~imw/gif/pujaw.gif A sketch of remains from Beckle’s mammal pit, including P. becklesii. A second site in the area, Ensom’s mammal pit, is currently a significant source of further fossils.
Era Mesozóica, Mamiferos http://www.geocities.com/arturmesozoico/mesomami.html Some more sketches of Mesozoic mammals, including P. Yes, I think it’s based on the same specimen as in the previous link too. Multituberculate jaws don’t grow on trees. |
| Species: | Plagiaulax dawsoni Woodward, 1891 |
| Place: | Wealden, Wadhurst Clay, St Leonards (nr. Hastings) |
| Country: | England |
| Age: | Lower Cretaceous |
| Remarks: | This was based on an isolated tooth which was
later damaged, leaving a root fragment. Twenty years later, a couple of futher
isolated teeth became involved for a while. This name was only provisional, and it
wasn’t connected to a detailed description. Be that as it may, it was bestowed in
honour of Charles Dawson, who, in a fictional account By Irwin Schwartz,
posthumously confessed to involvement in the Piltdown Man hoax, (Eoanthropus
dawsoni). Whoever was really responsible, and that remains unknown, sure fooled
Woodward. Talking of tampering As of December 2006, I've fallen into pleasing correspondence with an erstwhile paleontologist named Eric Freeman. Among the treasures brought by the postal service this morning is chapter two of a book on Piltdown Man by Miles Russell (2003). Accoding to his researches, this fossil was very possibly tampered with before Woodward acquired it from Dawson. It was unusually well worn: "It was the patterning of wear that most seemed to perplex the young geologist, especially as the abrasion had not been produced 'entirely by an upward and downward or antero-posterior motion, of which the jaws of the know (sic) Multituberculata seem (sic) have been alone capable'", (p.29). Much later, the sidewards erosion was found to have been inflicted through extensive (and apparently creative) rubbing. "In short, P. dawsoni is a fake" (p.30). This artificially inflicted damage is also remarkably similar to that observed on the teeth of the Piltdown fellow. Who done it? Russell does go into this matter but, as it's a kind of Krimi, I'm not going to spoil things by addressing that question here. Many thanks to Eric Freeman. |
| Reference: | Woodard A Smith (1891), On a mammalian tooth from the Wealden formation of Hastings. Proc. zool. Soc. London, p.585. |
| Links: Clemens WA, Wealdean Mammalian Fossils, Paleontology 1963 http://www.clarku.edu/~piltdown/map_gen_hist_surveys/fossils_of-Pilt.html A review of then known mammals from the English Lower Cretaceous. The tooth gets mentioned in both these links.
Irwin Schwartz, The Piltdown Confession
An edited, (and FICTIONAL), version of Charles Dawson’s confession. 'Written' in 1916, it was 'intended' for publication in 2008, but actually appeared in 1994. (Irwin Schwartz wrote it.) As well as himself, pseudo-Dawson cites the active involvement of Father Teilhard de Chardin and William Abbott, as well as the compliance of Arthur Conan Doyle. (In a separate farce, the creator of Sherlock Holmes was fooled by photos of alleged fairies from Yorkshire.) As someone recently observed, a problem with intelligent people, is that they can think up very clever ways of being stupid. |
| Species: | ?Plagiaulax falconi |
| Place: | |
| Country: | |
| Age: | |
| Remarks: |
The title of the reference is all I know. This baffles me. Microlestes antiquus is
now known as Thomasia antiqua. The identity of P. falconi is presently
a mystery to me. Update: It seems likely this has become 'Bolodon' falconeri, a species presently housed in the wrong genus. |
| Reference: | von Plieninger T (1859) Microlestes antiquus teeth compared with Plagiaulax falconi. Verh. Ges. Deutsch. Naturforsch. Arzte XXXIII 94. |
| Species: | Plagiaulax sp. |
| Place: | Galve |
| Country: | Spain |
| Age: | Barremian, Lower Cretaceous |
| Remarks: | |
| Reference: |
| Other reports: Xxxxxxxxxxxx Xxxxxxxxxxx |
A. Plagiaulacidae B
Albionbaataridae C. Eobaataridae & Arginbaataridae
Small euro-teeth, which once inhabited small euro-mouths, though long before Europa was
seduced by Zeus.
Genera: Albionbaatar,
Kielanobaatar, Proalbionbaatar,
other reports
Time-Line:
Lower Cretaceous: Albionbaatar, Kielanobaatar, North-east China
Upper Jurassic: Proalbionbaatar
'English hero'
Remarks: 'Albion' is the oldest known name for England and may be Celtic. Baatar is
Mongolian and means 'hero' or 'warrior'. Given that we’re talking about vegetarians,
warrior seems the less appropriate alternative. An old spelling is bagator, as reflected by
the Russian word, bagatir. The root is bahtur (Modun Shan-Yu Hun).
Link:
Shirchin Baatar, Mongolian Great Gobi
He also knows much about the history, culture, geography and etc of Mongolia. I didn’t
find any information on Mesozoic Mammalia, though there are several items about dinosaurs.
I’ll never again think of the Gobi as being a large desert. A fine homepage with some
appealing audio accompaniment.
Dr Ian West, Bibliography of the Purbeck Formation, Dorset, UK - Vertebrates
http://www.soton.ac.uk/~imw/purbdin.htm
This is part of an excellent guide to the paleontology and geology of a very beautiful
corner of the world. Dorset has yielded many interesting fossils; for example, there’s
me.
Palaeontology 37
http://palaeontology.palass-pubs.org/pdf/Vol%2037/Pages%2017-31.pdf
Kielan-Jaworowska & Ensom, 1994 is presently freely avaialable in pdf format.
Remarks: Presently, I've seen nothing other than the abstract.
'before English hero'
North-east China
"?Valanginina or ?Hauterivian of north-east China (Wang et al. 1995),"
(Kielan-Jaworowska & Hurum, 2001, p.415). This refers to undescribed but
Albionbaatar-similar premolars.
A. Plagiaulacidae B
Albionbaataridae C. Eobaataridae & Arginbaataridae
Arginbaataridae Hahn G & Hahn R, 1983
References: Kielan-Jaworowska, Dashzeveg & Trofimov (1987), Early Cretaceous
multituberculates from Mongolia and a comparison with Late Jurassic forms. Acta
Palaeontologica Polonica, 32, p.3-47.
Remains of the eobaatarids are known from Europe, Asia and possibly North America. In this
case, specimens aren’t restricted to teeth, thanks to a recent description from the
Liaoning fossil factories, (Sinobaatar). They were close relatives of the
Plagiaulacidae, whilst the second upper molar has
similarities to ones known from the informal Paracimexomys group.
'Dawn heroes', late in the evening for the plagis
Genera: Arginbaatar, Dipriodon (partly = Loxaulax),
Eobaartar, Hakusanobaatar,
Heishanobaartar, Liaobaartar,
Loxaulax,
Monobaatar, Parendotherium,
Sinobaatar, Tedoribaatar,
other reports
Time-line:
Lower Cretaceous: Arginbaater, Eobaatar, Hakusanobaatar,
Heishanobaatar, Liaobaatar, Loxaulax,
Monobaatar, Parendotherium, Sinobaatar, Tedoribaatar
Aka: Arguinbaatar
Family: Arginbaataridae Hahn & Hahn, 1983
Remarks: Kielan-Jaworowska & Ensom, 1992 informs (p.101):
'dawn hero'
Aka: Eobataar, Loxaulas sp. (partly)
Museo
http://adigital.pntic.mec.es/~tronchon/dinos/museo.htm
An attractive Spanish page concerning the collection of the museum at Galve, which houses
a number of mammal teeth, including E. hispanicas. Further local fossils include
remains of dinosaurs and pterosaurs.
Acta Palaeontologica Polonica
http://www.app.pan.pl/archive/published/app54/app20080003.pdf
Sweetman, 2009 is presently freely accessible on-line in pdf format.
Kusuhashi 2008, Acta Palaeontologica Polonica
http://www.app.pan.pl/article/item/app53-379.html
The description is presently freely accessible, via the abstract page, in pdf format.
Remarks: The same area has also yielded remains of a further, presently unnamed
eobaatarid. If that proves correct, then these two formations are now alive with five
eobaatars. Some might call that being greedy. In any case, it's an intriguing contrast
to the single known genus from Liaoning's Yixian Formation.
'Liao hero'
Remarks: Liao is an abbreviation of Liaoning, the province from which the material came.
I already happen to know it means 'far away' in English. Combined with 'ning', that
becomes 'far away' and 'quiet'.
Aka: Dipriodon sp.
"Butler and Ford reported some IoW Wealden mammal teeth several decades ago. They
identified one of the teeth as belonging to the
multituberculate Loxaulax but weren't sure about the others. Other IoW Wealden
mammal teeth have been found since but have yet to be written up," (with thanks to
Darren Naish).
The Isle of Wight Wessex Formation - Lower Cretaceous
The following is based upon my reading of Sweetman SC, 2004.
Link:
DinoWight
http://www.dinowight.co.uk/
'single hero' Remarks: Monobaatar is very poorly known. It's tentatively
placed within Eobaataridae by Kielan-Jaworowska & Hurum (2001), but probably
doesn't belong (p.415). It's gotta go somewhere!
'Beside Endotherium'
'Chinese hero'
Chinese Science Bulletin 47 (11)
http://www.scichina.com/ky/0211/ky0933.stm
The abstract.
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Should anybody have any further information, I'd be pleased to hear of it.
Regarding references and Bibliography:
With thanks to all the featured sources.
Trevor Dykes, October 2001 Last update: 27.10.2011
The Society of Vertebrate Paleontology's Bibliography of Fossil Vertebrates (John
Damuth)
BIOSIS: The Index to Organism Names
http://www.biosis.org.uk/triton/indexfm.htm
Shirley Sparks, for kindly supplying the paper by Dr Savage.
B. ALBIONBAATARIDAE
Taxon: Albionbaataridae Kielan-Jaworowska Z & Ensom PC, 1994
Expressed rather more knowledgeably: "Shrew-sized taxa
that differ from all other multituberculates in
having relatively flat, multi-cusped anterior upper
premolars, with 10-14 cusps arranged in three rows, rather then 3-4, rarely up to nine
high cusps in two rows, and in having lingual slope of all
premolars covered by prominent, subparallel ridges...," (Kielan-Jaworowska &
Hurum, 2001, p.414).
Genus: Albionbaatar
Kielan-Jaworowska Z & Ensom PC, 1994
For this information I’m indebted to Shirchin Baatar, who clearly knows the etymology of
his own surname.
Species: Albionbaatar denisae Kielan-Jaworowska Z & Ensom PC, 1994
Place:
Purbeck Limestone Group, Dorset
Country: England
Age: Berriasian, Lower Cretaceous
Remarks: The following is based upon my reading of
Kielan-Jaworowska & Ensom, 1994.
Remains of Albionbaatar are both scarce and small, but size isn't all that
important. At least, that's what my wife tells me. Mammal paleontologists expend much
time studying molars. In this case, these most informative
of teeth haven't been found. Fossils are presently restricted to a few
premolars and they happen to differ significantly from
any preciously known (p.17). Subsequently, an earlier relative was discovered from
Guimarota in
Portugal; Proalbionbaatar. Albion's upper p5
premolar has three rows of small, numerous cusps, and there's a ridged slope located on
the lingual side. Such a slope is known from other
'plagiaulacidans' but the ridges were a new
feature.
Profile of a premolar
The holotype is a P5 premolar in a fragment of upper jaw (p.19), and company is provided by
a second isolated P5, and three tentatively assigned upper premolars from other positions.
A couple of partial lowers could be corresponding teeth, but that's not clear.
The P5 is shaped vaguely like a figure of eight thanks to centrally located bays on both
the lingual and labial sides. It's small even by multi
standards; length 1.4mm, width 0.85mm. This suggests a mammal of shrewish dimensions. The
cusp formula is (labial to lingual) 5-7, 7, 7. The labial row is shorter than the other
two. Cusps generally become smaller from front to back. The rear wall of the tooth has a
centrally located, somewhat pointed bulge while there's a concavity at the front. This is
consistent with an interlocking mechanism to enhance stability of the tooth row.
Cusps
The seven lingual cusps have ridges running from them, and these carry on to a slope at the
margin of the crown Some of the middle and all of the rear ridges also branch. The amount
of wear evident varies from none (to the front) to heavy (at the rear, p.20). The labial
cusps are more variable in size than is the case for the other two rows, and the number is
probably restricted to five. The area behind those cusps is given over to crenulations and
cuspules. There's an extra cusp on the labial margin of the tooth, and this occurs at a
position between the second and third labial cusps.
Other premolars
Possible candidates have been identified for the positions of P1, 2 and 3. As would be
expected, these are all smaller and more simply built than the P5 (p.22-24), as the latter
served as an active part of the grinding equipment in multi
dentitions (excepting for some basal cases). Each has
three rows of cusps, and these crowns vary in outline from near rectangular to trapezoid.
Why were five isolated teeth referred to the same species?
The sizes are compatible, they all bear characteristically conical cusps of multituberculates
and come from the same fauna (p.24). Furthermore, the cusps are unusually small and
numerous, arranged in three rows and ridges run onto the lingual slopes, as mentioned for
the P5. The positions have been deduced by comparisons with what's known from other
similarly aged multis. The proportions help identify the P5s, as the ultimate premolars
are elongated (p.25). This applies for both 'plagiaulacidan' P5s and
cimolodontan P4s, teeth which are presumably
homologues. The other premolars are tentatively assigned to positions.
Lower teeth
Two fragments of p4 premolars were collected (p.25-26). Assigning them to a particular
multi isn't presently possible. However, it can't be ruled out that they could be from this
species.
'English hero', its place in Multidom
Details of structure debarred the genus from any established family, as implied by the
erection of a new one. The narrowness of the P5 premolar disqualified it from affinities
with paulchoffatiids. The
lingual slope does occur in other 'plagiaulacidans' from Dorset, but not in this form
with ridges (p.27). This tooth would also be unusually long for such critters, with a
length-width ratio of 1.64:1. (Bolodon osborni manages 1.6:1,
so the difference isn't too extreme for credibility.)
Of more significance is the distinctive nature of the cusps. These are all of fairly
similar sizes and arranged in three rows. The general fashion was for larger cusps
organised into one and a half to two rows. They're also unusually numerous, as the holotype
boasts of nineteen and the referred P5 manages 21. Allodontids had a total of six to seven
on the equivalent teeth. Among other plagis, Eobaatar takes
things to an adventurous total of eight. The mathematically gifted will conclude this is a
much lower number than for 'English hero'.
That raises the question as to whether this genus might've been a relatively early cimolodontan,
but the answer is no. The lingual ridge isn't found on cimolodontan P4s (the equivalent
premolar). Furthermore, taeniolabidid P4s are
typically more reduced. For eucosmodontids and many ptilodontoids (in the terminology of
the paper), there's a complete lingual cusp row combined with a shorter buccal one restricted
to the front.
That situation changes for some later ptilodontids.
Those P4s became cuspier with two full rows and a partial buccal one. In terms of cusp
numbers, Ptilodus and
Prochetodon can have 20 cusps on a P4, and that's similar to Albionbaatar.
Nevertheless, there's no ridged lingual slope. The other referred premolars seem even more
aberrant. The crowns are unusually flat with ten to fourteen similarly sized cusps in three
rows. More orthodox systems involved two rows of up to nine higher cusps.
Small and rare
Multi teeth of this diminutive size hadn't previously been found, and this may reflect the
prospecting methods employed. In this case, mesh sizes went down to one third of a
millimetre. Often, the smallest sized mesh used had been a millimetre (p.28) and, as all
these Albionbaatar teeth are smaller than that in one dimension or another, they may
have evaded detection by such attentions.
Holotype
The type fossil, DORCM GS 212, is an upper premolar (P5) in the collection of the Dorset
County Museum, Dorchester. The specific name honours Denise Sigogneau-Russell in
recognition of her extensive research into Mesozoic mammals. Reference: Kielan-Jaworowska & Ensom (1994), Tiny plagiaulacoid
multituberculate mammals from the Purbeck Limestone Formation of Dorset, England.
Palaeontology, 37, p. 17-31.
Links:
Genus:
Kielanobaatar Kusuhashi N, Hu Y, Wang Y, Setoguch T & Matsuoka H, 2010
Species: Kielanobaatar badaohaoensis Kusuhashi et al, 2010
Place: Shahai or Fuxin Formation, Liaoning Province
Country: China
Age: Aptian-Albian, Lower Cretaceous
Remarks: This seems to be based on upper
premolars. Reference: Kusuhashi et al (2010), New multituberculate mammals from the
Lower Cretaceous (Shahai and Fuxin formations), northeastern China, Journal of Vertebrate
Paleontology, 30(5), p.1501.1514.
Genus: Proalbionbaatar
Hahn & Hahn, 1998
Species: Proalbionbaatar plagiocyrtus Hahn G & Hahn R, 1998
Place: Guimarota
Country: Portugal
Age: Kimmeridgian, Upper Jurassic
Remarks:
One of twenty species of multi identified from
this location. This seems to have been the most derived of
them. Remains consist of two isolated upper molars, which
are smaller than the corresponding teeth of paulchoffatiids, (the best represented multi
group of Guimarota). They also have more cusps, which are arranged in two rows. (Hahn
& Hahn 2000, p.106).
Mit bestem Dank an David Marjanovic. Reference: Hahn & Hahn (1998), Neue Beobachtungen an Plagiaulacoidea (Multituberculata) des Ober-Juras 4. Ein Vertreter der Albionbaartaridae im Lusitanien Portugals in Berliner geowissenschaftliche Abhandlungen E 28, p.85-89.
Other
reports:
Reference: Wang Y, Hu Y, Zhou M & Li C (1995), Mesozoic mammal localities in western
Liaoning, northeast China. p.221-227. in Sun A & Wang Y (eds.), Sixth symposium on
Mesozoic terrestrial ecosystems and biota. Short papers. Ocean Press, Beijing, vi + 250p.
C. EOBAATARIDAE AND ARGINBAATARIDAE 
Taxon: Eobaataridae Kielan-Jaworowska Z,
Dashzeveg D & Trofimov BA, 1987
Hahn & Hahn (1983), Multituberculata. In Westphal F (ed), Fossilium Catalogus, I:
Animalia, Pars 127. Kugler Publications, Amsterdam, p.409.
Kielan-Jaworowska et al, 2000 contains some general points (p.586). In contrast to
other 'plagiaulacidan' multis (excepting for
Glirodon), the enamel on lower
incisors is reduced to a limited band for
eobaartarids. Lower molars are longer on the
buccal side then the
lingual one. The tooth enamel is also unusual as it's arranged into large
prisms (gigantoprismatic). This is otherwise only known from
Arginbaatar and many of the more advanced
Cimolodonta gang. The number of lower
premolars was three per side, as with some plagis.
Others had four. However, they're comparatively small teeth apart from the final
one.
The monotypic family of Arginbaataridae is of uncertain affinities.
The following has resulted from my reading of Kusuhashi, 2008.
As presently known, multituberculate mammals
fall into three groups; somethings, plagis and cimolods. The somethings are a small
collection of isolated teeth from the Middle Jurassic of England; eg.
Hahnodon, one of the earliest multis found so
far. Let's call them the ancients and turn to the plagis, themselves archaic by the latter
Lower Cretaceous. Plagis don't add up into being a natural taxon;
one ancestor and all of its descendants. Not enough is yet known to securely define such
a unit as a robust Plagiaulacida and, therefore, these
"plagiaulacidans" are forced to wear inverted commas (or some such device) as
acknowledgements of their disgrace. The situation differs for the now long extinct
moderns of Cimolodonta. Those cimolods are united
by inherited characteristics bequeathed them by a founding father or mother.
Among these inheritances are: reduced numbers of premolars with (above) four per side and
(below) only two or later just one; a lower premolars (presently termed p4) typically
resembling something like part of an upturned oyster shell, an arc-shaped blade at the top
with numerous serrations, most of which are found in association with ridges running down
the sides of the tooth crown. Generally plagis, on the other paw, were toothier in
premolar numbers. And, in some of the earlier birds,
paulchoffatiids, upper rear premolars aren't notably adapted for shearing although, to
some degree, the lowers had potentially useful features (Hahn & Hahn, 2000 p.100).
Gradually, as plagi history unfolded, shearing specialisations became more pronounced.
Cimolod ancestors
As this funny named "Plagiaulacida" presently contains all non-cimolod multis excepting for
those Middle Jurassic ancients, and as cimolods did have non-cimolod ancestors, then that
ancestral lineage has to be plagi in the necessarily crude terminology. Some plagis, then,
must have included prototypes of cimolod traits. And the global host of multi-fans would
dearly love to meet and thank them for the diversity of their descendants and, of course,
for their own efforts at life on Earth. However, such expressions of heart-felt
gratitude are dependant upon actually both finding and recognizing (correctly recognizing)
fossils from the little bleeders. There once lived a link between the then extant
archaic plagis and the future cimolod moderns; an evening for plagi-ism that was succeeded
by the cimolod dawn.
A found link?
Eobaataridae, a relatively late plagi family, happens to have been around at just the right
sort of time, and dental developments also happen to be pointing in cimolod directions.
As ancestral suspects go, they're the strongest candidates presently available. Should any
members of the police be looking into just who gave rise to those more derived multis,
then Tedoribaatar should be placed high on the list of
animals you should be interrogating. It's one of two eobaats from the Kuwajima Formation
of central Japan, a place which can boast of an increasingly diverse fauna of Lower
Cretaceous eucynodonts; both mammalian and
exquisitely late non-mammal tritylodontids.
Actually, as the place is delivering the goods, such a claim shouldn't really be termed
a 'boast'.
Genus:
Arginbaatar Trofimov BA, 1980
The p4 lower premolar is unusually big and has limited
enamel. As the animal grew up, this tooth gradually rotated until it covered the space
occupied by p3 and p2, and those premolars were then discarded. The lower
incisor was completely enamelled and there was a
canine. These are 'old fashioned' features for multis. As
with eobaartarids and later taeniolabidoids, tooth
enamel was arranged into large prisms; ie. it was gigantoprismatic.
A plagi of some kind or other, this is the only known
member of its family, which is thus monotypic. Some characteristics are
'Plagiaulacida'-like, whilst others are more akin to the further derived
Cimolodonta. Quite where it fits in is unclear.
"This family shows a mixture of 'plagiaulacidan'
and cimolodontan characters, (Kielan-Jaworowska & Hurum, 2001, p.415).
It was a decidedly small animal.
Species: Arginbaatar dmitrievae Trofimov BA, 1980
Aka: A. dimitrievae; Arguinbaatar dimitrievae
Place: Höövör
Country: Mongolia
Age: Aptian or Albian, Lower Cretaceous
Remarks: Kielan-Jaworowska et al, 2000 (p587-588)
provides a brief introduction.
This multi is the most common one known from Höövör, and it's representated by bits
of both upper and lower jaws. The skull lenght was about two centimetres. While
its possession of five upper premolars per side is
a trait shared with plagis, other characteristics bore some resemblance to
Nessovbaatar, a Mongolian
cimolodontan.
Lower teeth
The premolar count is high and old-fashioned compared to cimolodontans, three down
and five up. Of the lowers, p1 was dispensed with by the ancestors. The first
tooth present is thus p2, and this is followed by a double-rooted p3. However, the
p4 is much longer; seven times the length, and it packs in 15 to 18 serrations. As
the animals aged, that tooth gradually rotated over the ruins of the first two
premolars and, if the critter lived long enough, that pair disappeared. This is a
double-rooted tooth on which the rear one is the larger. The first molar is much
shorter than the p4 by a factor of 2.7, and its cusp rows contain three and two
members
(buccal:lingual).
Upper teeth
It's possible an upper canine was part of the
armoury. If so, then that's a very archaic tooth for a Lower Cretaceous multi mouth.
Both the final premolars are similar to one another,
and have two cusp rows. The first upper molar has two
rows of cusps (3:4), whereas M2 manages three (1:2:3).
Holotype
PIN 3101/49 is part of a right lower jaw, and it may be visited at the Paleontological
Institute, Moscow.
The spelling variations are listed in Averianov & Skutschas 2000, (p.340). I was using
the first one myself. Reference: Trofimov (1980), Multituberculata and Symmetrodonta from the
Lower Cretaceous deposits in Mongolia. Trans. (Dokl) USSR Acad Sci, Earth Sci Sect 251.
p.209-212.
Genus:
Eobaatar Kielan-Jaworowska Z, Dashzeveg D & Trofimov BA, 1987
Species: Eobaatar magnus Kielan-Jaworowska Z, Dashzeveg D
& Trofimov BA, 1987
Place: Höövör, Guchin Us County
Country: Mongolia
Age: Aptian or Albian, Lower Cretaceous
Remarks: Brief details are found in Kielan-Jaworowska
et al, 2000 (p.586-587).
An estimate of the skull length suggests three centimetres, and that's enough for
this to be the giant from the two Höövör species. Viewed from the external side,
the p4 premolar has been described as being
rectangular in an approximate use of the word. These teeth range in length from
3.1 to 3.6 millimetres and bear 9 to 10 serrations. Of the lower
molars, the first has cusp rows with 4
(buccal) and 2 (lingual)
members, and the second of the buccal row is the largest of all. The m2 scores
3:2. The first upper molar has three to four cusps whereas its M2 partner manages
three rows (1:3:3).
Size
Kusuhashi, 2008 contains some dental dimensions on page 385. I'm just noting the
lengths here.
Lower premolars: p4 (2 specimens) 3.0-3.5mm.
Upper molars: M1 (1 sp.) 1.8mm.
Holotype
PIN 3101/57 is a left p4
premolar imprisoned at the Paleontological Institute, Moscow. At least a
dentary fragment is known. Reference: Kielan-Jaworowska et al (1987), Early Cretaceous
multituberculates from Mongolia and a comparison with Late Jurassic forms. Acta
Palaeontologica Polonica, 32, p.3-47.
Species: Eobaatar minor Kielan-Jaworowska Z, Dashzeveg D & Trofimov BA, 1987
Place: Höövör, Guchin Us County
Country: Mongolia
Age: Aptian or Albian, Lower Cretaceous
Remarks: Brief details are found in Kielan-Jaworowska
et al, 2000 (p.587).
This species is both smaller than E. magnus and rarer, with both coming from
the same fauna. The size difference is considerable; an estimated skull length of
one centimetre rather than three. Should the type fossil, part of a jaw, happen to
be from anything like an adult animal, then it must've been near to the minimum
size for mammals. The jaw fragment has remains of the lower
premolars and an
alveolus for the single incisor. The first
premolar, p2, is only shown by its alveolus. Fragments remain of p3 and the front
of p4. This final preserved tooth seems proportionately lower and shorter then the
equivalent on the larger sister, and the ridges running from the serrations are
fainter and more closely packed.
Holotype
The type fossil, PIN 3101/70, is part of a right dentary housed at the Paleontological
Institute in Moscow. Reference: Kielan-Jaworowska et al (1987), Early Cretaceous
multituberculates from Mongoloia and a comparison with Late Jurassic forms. Acta
Palaeontologica Polonica, 32, p.3-47.
Species: Eobaatar hispanicus Hahn & Hahn, 1992
Place: lower Camarillas Formation, Galve
Country: Spain
Age: lower Barremian, Lower Cretaceous
Remarks: The following is based upon my reading of
Hahn & Hahn, 2002, and not the original description. I haven't read that.
In this short, German language paper the Hahns tended to the descriptive needs of a
couple of isolated upper premolars obtained from
deposits in Galve (p.257). One was referred to this species whereas the other, a
tetracusp tooth, was despatched to the genus of
Galveodon. Quite which of the three fossil-yielding horizons they came from
is unknown. When described, they were members of a collection in the possession of JM
Herrero, a local resident. For all I know, they still are.
The upper premolar the Hahns allocated to this species if a tri-cusped tooth with a length
of 0.9mm (p.258). Both the front and rear edges of the crown are damaged and the roots,
of which there were two, have been broken off. The cusps form a triangular arrangement
with two at the front and a larger one at the rear. The front pair share similar sizes.
The cusps haven't been affected by wear, and are decorated with clearly developed ridges
running down from the apices.
This specimen is somewhat smaller than the two teeth described previously, but not much
so, and the Hahns attribute differences as being matters of intraspecific variation.
Determining whether this might be a P1, 2 or 3 wasn't discussed. It's from one of those
positions or another. Reference: Hahn & Hahn, 1992, Neue Multituberculaten-Zähne aus der
Unter-Kreide (Barremium) von Spanien (Galve und Una). Geologica et Palaeontologica, 26,
p.143-162.
Link:
Species: Eobaatar? parjaronensis Hahn G & Hahn R, 2001
Place: Ple pajaron
Country: Spain
Age: Barremian, Lower Cretaceous
Remarks: Don’t forget the question mark! Reference: Hahn & Hahn (2001), Multituberculaten-zahne aus der Unter-Kreide (Barremium) von PIe Pajaron (Prov. Cuenca, Spanien).
Paläontologische Zeitschrift 74 ( 4), p.587-589.
Species: Eobaatar clemensi Sweetman, SC, 2009
Aka: Loxaulax sp.
Place: Wessex Formation, Isle of Wight
Country: England
Age: Barremian, Lower Cretaceous
Remarks: The following is based upon my reading of
Sweetman, 2009.
Back in the mid 1970s, Butler & Ford reported the discovery of a couple of multi teeth
from the Wessex Formation of the Isle of Wight (p.373); an m2
molar and an I3 incisor. The first was poorly
preserved and both were tentatively referred to the genus of Loxaulax. More
recently obtained and better condition Isle of Wight fossils provide grounds for revision.
The genus responsible appears to be the subsequently established Eobaatar, a multi
known to have enriched the wildlife of Mongolia and Spain as well.
A third of a century ago, those two teeth were the only mammal remains to have been
obtained from the Wessex Formation, and that was somewhat frustrating. Conditions
suggested suitable localities could have been available somewhere or other. The only
problem was finding them. Bulk processing of sediment was attempted, most notably by
Eric Freeman (p.374). My correspondence with him leaves me thinking that, had more time
been available, then he would've come up with the cherished goods. However, his
attentions got deflected, with much success, into the Middle Jurassic of Oxfordshire.
Even the most determined and imaginative of ancient mammal hunters haven't yet cracked
the secret of being in more than one place at a time, and that's despite occasional
appearances to the contrary.
In 2002, the challenge was picked up by Steve Sweetman, certainly now an Isle of Wight
resident. As said, conditions suggested suitable localities should be available
somewhere. This formation is part of the Wealden Supergroup, a depositional sequence
which occurs in southeastern England (with three mammal localities in Sussex), disappears
under the sea, pops up again on the east and west coast of the Isle of Wight, and then
cuts across the sea again to continue as a thin band of exposures across the Isle of
Purbeck peninsula about ten miles or so from where I was born and grew up. Sweetman went
out, persevered and found some Isle of Wight localities.
The most generous of the several sites on both the southeast and southwest coasts is at
Yaverland, not all that far from the Dinosaur Isle Museum in Sandown. (In some parts of
the world, fossil localities are found in God forsaken deserts and other inaccessible and
inhospitable places. In southern England, we prefer them to be within walking distance
of a bus stop, pubs, chip shops, ice cream sellers and other essential facilities.) So
far, Yaverland has yielded teeth of at least five taxa of
mammals. Presently, there are no generic overlaps with the small known menagerie of
Sussex although larger sample sizes, should they become available, could conceivably
provide some (p.375). The multi, Eobaatar, is also present in the Barremian of
Spain. So, in addition, is a family representative of gobiconodontid
triconodonts.
Lower molars
The m1 has a cusp formula buccal -
lingual of 3:2. The buccal length of the crown is longer than the lingual side (1.4mm
rather than 1.1, p.378), and the width amounts to 0.9mm. The lingual cusps are higher
than the buccal ones, as seems universal for all
"plagiaulacidans". The front margin runs straight across whereas the rear one cuts a
more diagonal course. That results from the difference in length of the sides. Roots have
gone. However, both are at least partially present on a second specimen.
Lingual cusps are crescent shaped with the open side to the lingual flank. The first of
the pair is the longer. Effects of wear can be seen on the buccal part of the rear of the
crown. This extends towards the front of the second cusp, but the degree of wear lessens.
Further wear can also be found in the valley between the cusp rows, but it's only
light (p.379).
There are three main buccal cusps in a manner of speaking. Two occupy the front half of
the crown, whereas the third is involved in a structure on the other half. The leading
cusp of the row is the smallest of the trio while number two is both the largest and
tallest. Wear has produced a facet on its front lingual area. The third is a single
cusp but with two peaks (cuspules) separated by a pit between them. The rear peak is
smaller and has suffered some erosion, either from wear or abrasion. (The possibility is
noted that this structure could have developed from two distinct cusps coalescing
together, rather than from an ancestral single cusp dividing.)
Family affair
Similarities were recognized to be closest with the m1s of eobaatarids but, as that tooth
isn't known for all relevant taxa, direct comparisons aren't presently possible in all
cases; eg. E. minor and E. hispanicus. For the first named, the geographical
and chronological distance involved would make membership of the same species improbable.
Furthermore, this m1 would be surprisingly large for E. minor. In terms of time and
space, Spain's E. hispanicus seems a more likely candidate (p.380). In that case
though, the upper known upper premolars appear too large
for potential membership of the dentition of the same species as this molar. Consequently,
referring the Isle of Wight specimens to an already established species lacks plausibility,
and setting up a new, poorly known one was seen as justifiable. Naturally, that conclusion
could change in the light of presently unknown evidence.
A second, slightly larger molar was also referred to the new species as was, on a tentative
basis, the heavily worn tooth previously assigned to Loxaulax sp.. An upper
incisor is a further possible candidate for inclusion (p-382).
Holotype
BMNH M 45482 is attracting vast crowds to the Natural History Museum in London. The same
collection also has a further molar that's been named as the paratype. And then there's
the pair of specimens found in the 1970s and tentatively assigned (one now in London,
another in Stuttgart). All four actually come from different localities.
The specific name honours William A Clemens, a fanatical friend of mammals from the
Wealden age and all points of the Mesozoic chronological compass. Reference: Sweetman SC (2009), A new species of the plagiaulacoid
multituberculate mammal Eobaatar from the Early Cretaceous of southern Britain,
Acta Palaeontologica Polonica, 54(3), p.373-384.
Link:
Species: Eobaatar sp. Badiola A, Canudo JI & Cuenca-Bescos
G, 2008
Place: La Cantalera, Teruel
Country: Spain
Age: Hauterivian/Barremian, Lower Cretaceous
Remarks: The following is based upon my reading of Badiola et al,
2008.
This concerns material from La Cantalera that hasn't, as yet, been assigned to a species
of Eobaatar. A couple of upper premolars were
found at a locality that's most likely of Hauterivian age. If correct, then these
fossils are the oldest presently known for the genus and, indeed, the family of
Eobaataridae (p.1460). Both are P5s with one having a length of 1.63mm and a width of
1.35. The cusp formula (buccal -
lingual) is 2:4, and the tooth was double-rooted. The second buccal cusp is much
larger than its partner (p.1462). In the lingual row, the middle two are largest wheras
the leading and final cusps are similarly sized to each other in their more modest
dimensions.
The outline of the tooth, the layout and number of cusps, typify the condition for this
genus. Its size is close to E. magnus. However, the lingual cusps of that species
increase in height from front to rear, and there are further distinctions of detail. The
size is smaller than that of a P5 of Spain's E. hispanicus (length 1.92mm, width
1.2), and lingual cusps of that species also increase in size along the line. Consequently,
this Cantalera P5 is unlikely to belong to either of those species. However, greater
sample sizes could potentially reveal a presently unknown level of variability for such
features and so, for now, the premolars have to be content with only a generic
assignment.
Several rather anonymous multi teeth were also collected, but identifying affinities is
problematic. A P1 and a fragment of lower p4 could be from either an eobaa or a
plagiaulacid. Partial
incisors are "plagiaulacidan" (p.1464). Reference: Badiola, Canudo & Cuenca-Bescos (2008), New multituberculate
mammals from the Hauterivian/Barremian transition of Europe (Iberian Peninsula),
Palaeontology, 51(6), p.1455-1469.
Genus:
Hakusanobaatar Kusuhashi N, 2008
'Hakusan hero'
Remarks: The generic name refers both to Mount Hakusan and Hakusan City which, some may
correctly guess, are rather near each other. The Mongolian word for 'hero' got added on
as a matter of precedence for eobaatarids and other especially Asian multis. Hakusan City
used to get by as Shiramine Village. Anyway, as well as becoming a city it also opted for
a name change operation. I don't know why, but I wouldn't be surprised to hear if it had
something to do with tourist appeal. The name of the mountain's widely known.
Species: Hakusanobaatar matsuoi Kusuhashi N, 2008
Place: Kuwajima Kaseki-kabe locality, upper Kuwajima Formation
Country: Japan
Age: Barremian to Lower Aptian, Lower Cretaceous
Remarks: The following is based upon my reading of
Kusuhashi, 2008.
Six specimens have been assigned to this species
with confidence (p.381), and a poorly preserved upper premolar may also belong. This was
a fairly small member of a family, Eobaataridae, of smallings. A tentative dental formula
per side is available: (uppers): ?3 incisors, 0
canine, 5 premolars, ?2
molars; (lowers): 1, 0, 3 and ?2 respectively. The fossils
don't allow for complete certainty. However, there are such things as
multituberculate norms. The cusp formulae of the
last two upper premolars (buccal to
lingual P4 3:5, P5 2:6:?2) is a distinction from Eobaatar,
Monobaatar and
Sinobaatar. The P4 count also differs from
?Janumys as does a detail of the M1 upper molar.
Lower jaw and front tooth (it's meant to be singular!)
None of the available dentaries provide information on the
front or rear parts (p.382). Nothing, for example, is yet known of the coronoid process or
dentary condyle. There was a single incisor which is comparatively slender, has a rounded
lingual surface and a flatter buccal one. It's uncertain whether the sides were enamelled
but they could've been. As would be expected, there's no canine.
Lower premolars
A couple of p3s show an oval-shaped occlusal outline and
two roots for that tooth. The front root is thicker than its partner. The top of the
crown has two small serrations, with each featuring a small ridge. No obvious indentation
at the front hints at the presence of a p2 in front, however: "... the anterior margin is
indented upward, indicating the presence of p2."
Three p4s agreed to be interviewed. When viewed from the side, multi p4s can have a
rectangular sort of shape or, particularly popular with cimolods, be arcuate. That means
the top has an arch-like shape. It's somewhere between the two in this instance. The
length of the tooth is greater than its height, but not by much. Along its roof are found
ten serrations, at least eight of which have ridges running diagonally down on both sides.
The first and last are ridge-free zones although, in the second case, that could be due to
wear. At the rear, on the buccal side, a cusp occurs about
halfway between the final serration and the base of the crown. It's a double-rooted tooth,
and the back root is about twice as long as the front one.
Lower molars
Please feel free to find some. The present shortage is one reason why Hakusanobaatar
doesn't display much of an appetite. In any case, every adult multi that's ever been informative
upon this subject had two lower molars per side. Reasonably enough, the author tentatively
assumes that to also apply for this genus.
Upper incisors
Two positions are represented, I2 and I3. Both are single-rooted teeth (p.383). The
first mentioned is small, conical and has an even smaller cusp for company at the rear.
The thin I3 is described as leaf-shaped when seen from the front.
Many thanks, kind author!
I'm imposing a short interlude to propose a toast of thanks for the kindness shown in this
paper by Kusuhashi. There's something I can't remember ever having seen stated before.
When citing the numbers of cusps on the teeth of multis, there's a convention for the
given numbers to run from the buccal (or labial) to the lingual row. This is something
the author actually informs the readership of, and it only requires a couple of words.
Naturally, full-blooded specialists and hardly sane amateurs such as myself don't need
telling the obvious. However, I vaguely remember being slightly less insane at some
point in the past. Identifying and confidently unravelling that convention by yourself
can be damnably difficult should you have nobody to ask for advice, especially in the
context of having dozens of other examples of incomprehension whirling around as they
party in your brain.
Upper premolars
A full set contains five per jaw half. The first three are much of a muchness. Each has
a triangular arrangement of cusps, one buccal and two
lingual, with no great difference in their sizes. The
third tooth is somewhat smaller than the first two.
P4 is cuspier; 3:5 (as always buccal-lingual). This is similar to the corresponding
premolar of Eobaatar, albeit with a somewhat different
formula. The cusp heights in the buccal row are fairly uniform but the middle cusp is
larger. The first pair are close together (p.384), with the third favouring more
seclusion. Lingual cusps gain progressively in height from first to the fourth, and then
comes a small fifth one. The last three beat the buccal cusps for height, and all are
adorned with delicate ridges. Also of note is that the lingual wall of the crown forms a
shearing device.
A P5 is available on the type fossil. It has a rectangular occlusal outline and a cusp
formula of 2:6:?2. The middle cusp row shows jaunty inclinations. It commences on the front
lingual area of the crown, and parades along towards the buccal area of the rear. These
cusps are higher than their buccal colleagues (p.384). Perhaps they jeer down at them.
In any event, the third cusp is the highest of all, and there's then a sequential decrease
in height in both directions. A third row would've been located towards the back on the
lingual part of the crown. This is now a flattened area with a groove; the effects either
of wear during life, damage after death or perhaps some of each. The available space
suggests a former complement of two cusps or maybe more smaller ones.
Upper molars
Two specimens are known, both M1s, and the cusp formula is 3:4. All are of similar height
but the final lingual one is a touch bigger. The rear lingual corner of the crown also
hosts a crescent-shaped wing structure with no associated cusp. Ridges connect the cusp
rows at the back.
About the size of things
Various dimensions are given on page 385, but I'll just mention the lengths.
Lower premolars: p3 (2 specimens) 0.9-1.0mm; p4 (2 sp.) 3.2-3,5mm.
Upper cheek teeth: P5 (1 sp.) 1.7mm; M1 (2 sp.) 1.5-1.7mm.
Some eobaat generalities
Dimensions also appear for teeth from Tedoribaatar,
Sinobaatar and Eobaatar magnus.
The following generalities apply with no mentioned exceptions.
Lowers: p3 longer than high; p4 higher than long.
Uppers: P1 and P2 longer than wide; P3 length and width close to equal; P4 and P5 longer
than wide; M1 longer than wide.
The nature of the beast
Five upper premolars are too many for cimolodontans
and that leaves the present choice of plagi. However, it differs from all plagis,
excepting for eobaatarids and Arginbaatar, in the
reduced status of the third lower premolar. The p4 is about 3.5 times longer than that
tooth. This p4 is also less arcuate than is the case in cimolods and Arginbaat. It fits
best with eobaats, thus its admission to the family.
What's available is close in size to Eobaatar magnus and a bit smaller than
Sinobaat. The p4 premolar is of a similar build to those in both cases; more arched
than most plagis. The front upper premolars (P1 to P3) match the cusp numbers of Eobaat
and Monobaatar, although this feature isn't unique for
the eobaats.
Although similar to Eobaat, the upper P4 has five lingual cusps rather than just four; P5
has three cusp rows instead of two assuming, which isn't certain, the tooth has been
correctly identified for that genus. There are also points of distinguishment from other
eobaats, thus the need for a new genus.
An evolutionary recipe for making cimolods
The upper dentition is sadly incomplete. Nevertheless,
it happens to be to the best known for eobaats, and the premolar sequence is complete.
That allows scope for considerations on some evolutionary goings on in the development of
cimolods from plagis.
Cimolods have only four premolars on each half of the upper jaw (p.388). More
basal multis, the plagis, favoured five. One of them was
dispensed with by cimolod ancestors. Which one has been subjected to some debate. Although
these cimolod teeth get numbered 1 to 4, that doesn't necessarily mean the cimolod P4 is
a homologue of the plagi P4. Finding eobaat upper dentitions in good condition was likely
to cast some light upon the matter, seeing as eobaats were evolved towards cimolod
conditions. Until the discovery of Hakusanobaatar no complete upper premolar series
happened to be available. Kusuhashi came to the conclusion that it was the P4 that got
lost, and the cimolod P4 is actually derived from a plagi P5.
There's no real room for doubt about the first three positions. P1 to P3 are simple
things with a few cusps and little extravagance in both plagis and cimolods. The eobaat
P4 is more complex, and unlike a cimolod P3 (or a plagi one). However, no specimen from
any eobaat has more than two cusp rows and, on the lingual side, there's an increase in
height from the front to the rear. This bears no great similarity to a cimolod P4. The
eobaat P5 has more in common with that tooth.
Holotype
SBEI 1736 is a collection of jaw parts and teeth thought to come from one former owner.
It works at the Shiramine Institute of Paleontology, Hakusan City. Sometimes I wished I
did. The specific name honours Hidekumi Matsuo for both his efforts at the locality, and
his overall management of the research into the resultant fossils. Reference: Kusuhashi N (2008), Early Cretaceous multituberculate mammals
from the Kuwajima Formation (Tetori Group), central Japan, Acta Palaeontologica Polonica,
53(3), p.379-390.
Link:
Genus:
Heishanobaatar Kusuhashi N, Hu Y, Wang Y, Setoguch T & Matsuoka H, 2010
Species: Heishanobaatar triangulus Kusuhashi et al, 2010
Place: Shahai or Fuxin Formation, Liaoning Province
Country: China
Age: Aptian-Albian, Lower Cretaceous
Remarks: All I've presently seen is the abstract of the
description. That cites this critter as being a multi of modest size with a lower dental
fomula of (per side): 1 incisor, 0
canine, 3 premolars and 2
molars. Reference: Kusuhashi et al (2010), New multituberculate mammals from the
Lower Cretaceous (Shahai and Fuxin formations), northeastern China, Journal of Vertebrate
Paleontology, 30(5), p.1501.1514.
Genus:
Liaobaatar Kusuhashi N, Hu Y, Wang Y, Setoguch T & Matsuoka H, 2009
Species: Liaobaatar changi Kusuhashi et al, 2009
Place: Shahai or Fuxin Formation, Liaoning Province
Country: China
Age: Aptian-Albian, Lower Cretaceous
Remarks: As all I've presently seen is the abstract of
the publication, not much is known to me. For example, I don't know which formation
is the guilty party. This genus is comparatively large as the family goes, and the ratio
of the length and height of the p4 premolar is 1.9; ie. they're pretty similar. The
m1 cusp formula is 3:3.
The other two species described in the paper both belong to
Sinobaatar. Reference: Kusuhashi et al (2009), Two eobaatarid (Multituberculata:
Mammalia) genera from the Lower Cretaceous Shahai and Fuxin Formations, northeastern
China, Journal of Vertebrate Paleontology, 29(4), p.1264-1288.
Genus:
Loxaulax Simpson GG, 1928
Species: Loxaulax valdensis (Woodward, 1911) Simpson GG,
1928
Aka: Dipriodon valdensis Woodward, 1911
Place: Wealden, Cliff End bonebed,
Hastings
Country: England
Age: Valangian, Lower Cretaceous
Remarks: Two teeth from Hastings were originally described
by Woodward in 1911. Simpson established the genus later. Both were collected by Teilhard
de Chardin and Peiletier.
The location of this bonebed makes fossiling slightly tricky. "We have only found the
bone-bed material in quantity after the spring and autumn gales. This fact, coupled with
our failure to locate the bone-bed in situ in the cliffs, leads us to suppose that
the ultimate source of the material is an off-shore reef. Fragments of the bone-bed could be
dislodged from this by the intense wave-action of storms and thrown up on the beach. An
indication of the possible intensity of wave-action under these conditions is shown by a block
of the bone-bed weighing several tones, found balanced on a ledge 10 ft. up the cliff in the
autumn of 1961", (Kermack et al 1965, p.536).
Update
At least, that was there then conclusion about the bonebed. I've got a more recent
source of information to be incorporated at some time. The layer including the
Cliff End bonebed may be difficult to identify at the beach, but research shows it's
somewhere up towards the top of the cliff.
Another possible locality is the Camarillas Formation, Galve, Spain, (Canudo &
Cuenca-Bescós 1996, p.217).
Holotype
The holotype, BMNH 10480, is a resident at the Natural History Museum, London,
(Clemens 1963).
References: Woodward (1911), On some mammalian teeth from the Wealden of
Hastings. Q. Journal geol. Soc. London, 67, p.278. Simpson (1928), A catalogue of the Mesozoic Mammalia in the
geological department of the British Museum. London: British Museum (Nat Hist).
Isle of Wight Cretaceous Mammals
The friendly souls of the Isle of Wight Museum informed me that sieving is underway at one
fossil location, and I've heard from the researcher concerned. Steve Sweetman has
kindly taken the trouble to provide some details. Two multi teeth were found in the 1970s,
(a left I2 and a left m2). These are presently in Stuttgart.
Steve started work in May 2002, and now has over 25 new microvertebrate taxa awaiting
description. Mammals are rare. There's a lower molar (m3)
which isn't Loxaulax. It's probably something new. There's an upper
incisor which is from a larger multi, but more precise
identification might not be possible. The fact that's it's very well preserved makes
comparison with an equivalent from the mainland difficult. (That one's been rolled and
polished). Other material includes two therian
premolars and a partial lower jaw belonging to a
spalacotheriid. Thanks for the location report, Steve!
There will now follow a few words touching upon the Wessex Formation. Those of a
more anarchic spirit might prefer a more loosely written romp on the same theme.
A time courier service is available at:
Doing the Wessex walk,
the Isle of Wight during the Lower Cretaceous.
An alternative assault... I mean an account... I'm not sure. The manic Mesozoic
tourist guide strikes again. Light on mammals.
While this paper mainly concerns dinosaur (velociraptorine) teeth, it also offers some
information on the broader geology and paleo-ecology of the Wessex Formation, which has
yielded evidence of a diverse vertebrate fauna, (p.353). There were many plant-eating
dinosaurs around; ankylosaurs, ornithopods, sauropods and occasional stegosaurs. Among the
meat-eaters were an allosaurid (Neovenator) and an early tyrannosauroid
(Eotyrannus). Isolated fossils demonstrate the presence of coelurosaurs,
velociraptorines, what may be an oviraptorosaur and further theropods.
The best rock exposures are found on the southwestern coast, (p.354), and the thickness of
the formation comprises about 180 metres. A further 400 metres or so of strata account for
the rest of the Isle of Wight Wealden Group. The Wessex layers are non-marine in origin
and date from the Barremian stage of the Lower Cretaecous, (approximately 127 - 121 million
years ago). They're topped with a further 70 metres of lagoon sediments, (Vectis
Formation).
At the time when the Wessex Formation was being deposited, the area generally offered a
diverse array of habitats, though there's also evidence of seasonal aridity and inhospitable
droughts. The rock strata are punctuated by beds formed from plant debris. These seem to
have been dumped by a river on a floodplain near the coast. The water also carried in bones,
teeth and bodies of animals.
As well as the dinosaurs and occasional mammals the fauna also includes crocodiles,
pterosaurs, turtles, lizards, amphibians, sharks and bony fish. Most of these fossils have
yet to be described.
Further Mesozoic site summaries can be found at Localities.
Simon Clabby's homepage homage to the dinosaurs (and other Mesozoic inhabitants) of
the Isle of Wight.
Species: Loxaulax valdensis
Place: ?
Continet: North America
Age: Wealden, Lower Cretaceous
Remarks: This entry, which I suspect is simply wrong,
is in accordance with an internet listing by John H Burkitt. I've so far found no
confirmation for a presence of this species anywhere other than in the Wealden (Lower
Cretaceous) of southern England. Reference:
Genus:
Monobaatar Kielan-Jaworowska Z, Dashzeveg D & Trofimov BA, 1987
Species: Monobaatar mimicus Kielan-Jaworowska et al, 1987
Place: Höövör, Guchin Us County
Country: Mongolia
Age: Aptian-Albian, Lower Cretaceous
Remarks: A brief introduction's provided on page
588 of Kielan-Jaworowska et al, 2000.
Only upper jaw and teeth material are presently available from this mammal, which
had a skull length of about two centimetres (p.588). Remains show there to have
been five premolars per side, and the cusp formula
of P4 was 3:4 (buccal:lingual).
The second buccal cusp was the largest. An M2 molar
may also belong and its cusp formula is 1:2:3.
Holotype
The type fossil, PIN 3101/50, is part of a left maxilla
in the care of the Paleotnological Institute, Moscow. Reference: Kielan-Jaworowska et al (1987), Early Cretaceous
multituberculates from Mongolia and a comparison with Late Jurassic forms. Acta
Palaeontologica Polonica, 23(1-2), p.3-47.
Genus:
Parendotherium Crusafont-Pairó & Adrover, 1966
Species: Parendotherium herreroi Crusafont Pairó M &
Adrover R, 1966
Place: lower Camarillas Formation, Galve
Country: Spain
Age: lower Barremian, Lower Cretaceous
Remarks:
According to McKenna & Bell (1997, p.37) P. is a junior synonym of
Loxaulax. However, as Kielan-Jaworowska & Hurum (2001, p.415) and others list
it as a separate genus, so do I.
The upper premolar (P5) has two rows of cusps, (Canudo
& Cuenca-Bescós 1996, p.222).
Oringally...
Kielan-Jaworowska, Bown & Lillegraven, 1979 (p.242) provides some curious background
information, and many thanks to Eric for sending a copy of the book.
Back in 1966, the authors established this genus on the basis of an upper
incisor. The name suggests connections with
Endotherium which, at the time, was often
considred to be a possible eutherian. Whether that
case has any merit is difficult to assess, especially as all referred material
disappeared.
"From the name, one would suspect that satisfactory comparisons had been made with
the type of Endotherium. The figures of Endotherium, however, do not
allow adequate comparisons, and there is no real evidence that Parendotherium
is in any way related to the Manchurian mammal."
These three authors accused it of being a multi. An alternative suggestion was a
dryolestid. As a premolar has since been
discussed (eg. in 1996), the multi affinities must've won. Reference: Crusafont-Pairó & Adrover (1966), El primer representante
de la clase mamiferos hallado en el Mesozoico de Espana. Treuel 35, p.139-143.
Genus:
Sinobaatar Hu Y & Wang Y, 2002
Species: Sinobaatar lingyuanensis Hu Y & Wang Y, 2002
Place: Yixian Formation, Liaoning
Country: China
Age: Lower Cretaceous
Remarks: The following is based on my reading of Hu &
Wang, 2002. The description was originally published in Chinese, and the details
of the citation are not identical with this English language paper. The reproduction of
the text in my copy is sometimes less than clear.
The fossil record of multis prior to the Upper
Cretaceous is far scrappier than anybody would wish. Happily, when it got to learn of this
misfortune, the generous Yixian Formation decided to provide a reasonably complete skeleton,
(p.933). The animal wasn't fully grown and is mostly represented by impressions of both
its back and front in the positive and negative plates of rock. The skull's crushed but
nevertheless very welcome.
The teeth, and especially the postcanines, are similar
to those known from Eobaatar, which explains its
assignment to the family. They're intermediate between those of Upper Jurassic and later
animals. Unsurprisingly, the skeleton resembles other multis. The presence of an eobaatarid
also provided further support for the age of the Yixian, which had earlier been regarded
as somewhat debatable. Some of the Cretaceous residents were already relics.
Usually, if multis are found in a fossil fauna, they are among the most common of mammals.
Liaoning makes its own rules. This is presently the only representative of Multidom,
(p.934). A further rare touch is the preservation of limbs and feet. A typical Mesozoic
mammal no longer has a leg left to stand on, and paws are even rarer.
Skull
The skull is crushed, but it was narrow when in use. Fans of such things might bemoan the
lack of a superorbital crest or a postorbital process.
Teeth
The dental formula per side features: (uppers): three incisors,
no info on a canine, five
premolars and two molars; (lowers): one, nought, three
and two respectively.
Some lengths have been taken from Kusuhashi, 2008 (p.385). In each case they're for single
specimens. (As far as I'm aware, there still is only one known specimen. Still, my
radar system isn't quite perfect.)
Lower premolars: p4 4.1mm
Uppers: P4 1.7mm; P5 2.1mm; M1 1.8mm.
Uppers
The I1 is broken, but the root is a bit smaller than the second incisor, which is conical
in shape. The I3 has a small cusp at the back. The region where the
premaxilla and maxilla
meet is damaged on the left jaw and not exposed on the right, and that's why there's no
information on the presence or absence of a canine. Although multis didn't generally have
such teeth, they're known from basal forms.
For the premolars, P1 and 2 are damaged. However, like the other three, they were
double-rooted. P3 has a pair of cuspules and P4 is rectangular when viewed in the
occlusal perspective. The row of cusps on the
lingual side is higher than the row of small,
labial cusps. P5 is also rectangular, but it seems to have
three cusp rows, (though the print of my copy isn't terribly good on page 935).
Turning to the molars, M1 is also somewhat rectangular. There's one low cusp at the back
of the lingual side, a row of four in the middle, and three on the external side of the
crown. M2 is in the process of erupting, and the front is broader than the back. There's
a low, ornamented cusp on the labial, a row of three on the middle and four cusps on the
internal side.
Lowers
The incisor is conical and completely enamelled, which is
unusual for eobaatarids.
Multis generally have two (or even only one) lower premolars,
although basal members are known with four, (eg.
paulchoffatiids). Sinobaatar compromises with three; p2 to p4. The first is
single-rooted, reduced and facing oblivion, (p.936). The p3 is double-rooted and shaped
like the head of a spear. The final premolar is well on the way towards domination. It's
four millimetres long, a touch over 2mm in height, and blessed with eleven serrations. At
the time, this p4 was amongst the most effective plant slicers the world had ever seen.
Later, multis lengthened it further and added more serrations. They got rid of the p2 and
reduced the p3 to a remnant, (or junked it as well).
Part of an m1 is visible on the left mandible. The
labial side had four cusps, but the
lingual row isn't fully preserved. For the second molar,
the internal cusps are higher than those on the outer side of the tooth.
Feet
Impressions on both rock plates clearly show the morphology of the hand. Unsurprisingly,
it had five fingers. Much of the wrist is visible. Similarly, the rear paws are also
well preserved. Attempting any summary of the details here isn't something which would
serve any obvious purpose.
Comparisons
The dentition is similar to Eobaatar, which is
known from fragmentary jaws and isolated teeth. The known dental formula is the same, and
the p4 and lower molars share characteristics of shape and structure. However, in
Sinobaatar, the p4 is proportionately longer and has an extra serration. The lower
incisor is conical and fully covered with enamel, whereas in Eobaatar the tooth is
only enamelled at the front, and its shape is more like a chisel. The upper postcanines of
Sinobaatar have more ornamentation, and there are differences in numbers and sizes
of cusps.
Family affinities
Eobaataridae is presently placed with the suborder
'Plagiaulacida', (p.937). However, they have characteristics not present in other
members. There's one less lower premolar, (two less when compared to some cases), and the
p4 is also distinctive. Nevertheless, eobaatarids are clearly not part of
Cimolodonta; a suborder held to be
monophyletic.
Evolutionary developments
As the structure of the skeleton is broadly similar to later multis, the lineage remained
conservative in that respect. This contrasts with the more radical approach to dental
specialisation. Some further derived multis, (eg.
Ptilodus), show adaptations for living in trees.
Others, (eg. Kryptobaatar), were clearly
terrestrial. (As Krypto comes from the generally arid landscape of Upper Cretaceous
Mongolia, its experiences of trees must've been very limited.) Sinobaatar is more
of a generalist; at home in various terrains, but a master of none. Complete multi wrists
haven't previously been found, so comparisons are necessarily limited. With regard to a
non-multi: "In a word, the wrists of Sinobaatar and
Zhangheotherium are more similar to
each other. Their wrist morphology is not significantly specialized and may represent the
prototype of mammalian wrist. This kind of wrist is suitable for locomotion on the uneven
substrate." I think I'll add that, if you're a small mammal, all ground has a
tendency to be uneven.
Holotype
The holotype is IVPP V12517, and resides in the collection of the Institute of Vertebrate
Paleontology and Paleoanthropology, Beijing. The species name refers to the city of
Lingyuan. With thanks to Marcel Opitz for the notification. Reference: Hu & Wang (2002), Sinobaatar gen. nov.: First
multituberculate from the Jehol Biota of Liaoning, Northeast China, Chinese Science
Bulletin.
Link:
Species: Sinobaatar xiei Kusuhashi N, Hu Y, Wang Y,
Setoguchi T & Matsuoka H, 2009
Place: Shahai or Fuxin Formation, Liaoning Province
Country: China
Age: Aptian-Albian, Lower Cretaceous
Remarks: My information is presently restricted to just
the abstract. This species is similar in size to most family members althougha bit
smaller than S. fuxinensis which, in turn, is smaller than
Liaobaatar.
The m1 lower molar has a cusp formula of (buccal -
lingual) 3:2. The upper P4 boasts of 2:4 whereas the
P5 is termed blade-like. Upper molars have also been interrogated; M1 (4:4) and M2
(3:4). Reference: Kusuhashi et al (2009), Two eobaatarid (Multituberculata:
Mammalia) genera from the Lower Cretaceous Shahai and Fuxin Formations, northeastern
China, Journal of Vertebrate Paleontology, 29(4), p.1264-1288.
Species: Sinobaatar xiei Kusuhashi N, Hu Y, Wang Y,
Setoguchi T & Matsuoka H, 2009
Place: Shahai or Fuxin Formation, Liaoning Province
Country: China
Age: Aptian-Albian, Lower Cretaceous
Remarks: Given the specific name, this species has to
be from the Fuxin Formation.
The anterior upper premolars of this species have a stronger
cingulum at the back than those of S. xiei, and the M2 cusp formula is 3:3. As
one specimen reveals information on tooth replacement, there must be more known than
just isolated teeth. However, it's sadly unknown to me. I've not seen the paper. Reference: Kusuhashi et al (2009), Two eobaatarid (Multituberculata:
Mammalia) genera from the Lower Cretaceous Shahai and Fuxin Formations, northeastern
China, Journal of Vertebrate Paleontology, 29(4), p.1264-1288.
Genus:
Tedoribaatar Kusuhashi N, 2008
'Tedori hero'
Remarks: The generic name refers to the locality's local river, the Tedori. Baatar
is Mongolian for 'hero' and often gets used for these heroic critters.
Species: Tedoribaatar reini Kusuhashi N, 2008
Place: Kuwajima Kaseki-kabe locality, upper Kuwajima Formation
Country: Japan
Age: Barremian to Lower Aptian, Lower Cretaceous
Remarks: The following is based upon my reading of
Kusuhashi, 2008.
Presently, this genus is known only from a fragment of lower jaw containing but a single
tooth; a p4 premolar. However, it has the talent
required for stardom and, in terms of multituberculates,
perhaps even megastardom. It's very unlikely that the sex organs of this particular
individual were directly involved in the birth of the whole of
Cimolodonta but, despite the limited nature of the
remains, it does a bloody good demonstration of being guilty. Should you feel like
predicting the attributes of an ancestor for cimolods, then interview this critter before
beginning. It happens to look bang on.
These aren't claims made by the author.
Dental formula
Information is only available for lowers, and just a single tooth is preserved on the jaw
fragment. However, some evidence is also present for other positions. Tentatively, the
formula is (p.386): 1 incisor, 0
canine, ?2 premolars, ?2
molars. There are such things as multi typicalities to help out.
Small clues, big deal?
The single tooth is obviously a p4 premolar. In front and behind come the remains of
alveoli for further teeth; a p3 and an m1 molar that was
double-rooted. The premolar could perhaps have been double-rooted, but there's no
indication it was so. Ahead of its position is found another very small pit which could
be a remnant of a further alveolus. Its size is interpreted as being more in line with
having been for a discarded milk premolar (dp2). No evidence indicates a permanent p2
ever erupted to replace it. Now, it would be good to be able to check this against further
and more complete specimens. However, that can't yet be done.
When viewed from the side, the sole tooth, the p4, is neither rectangular, as with plagi
norms, and nor is it arched at the top (arcuate) a lá cimolods (p.387). It's transitional
between both states. There is a large "U-shaped anterior triangular lobe" (I've quoted as
I'm not entirely confident that refers to what I think it does!). One thing that's clear
even to me are the ten serrations along the top of the crown all of which, excepting for
the first and last, have diagonal ridges running from them down the sides of the tooth.
There's also a small buccal cusp. That's higher up than is
the feature for Hakusanobaatar, a possible
relative from the same locality. Of the two roots, the rear one is less than twice the
length of the front one, and that ratio is relatively low.
Transitional?
Even if the tiny pit isn't an alveolus for a deciduous
premolar, it's in the right sort of position for a p2 premolar. However, it's too small
to be for a permanent one, and other possibilities, eg a foramin for a blood vessel, are
improbable given this location on the jaw's occluding surface. And yet, despite that being
a normal p2 position, no mature tooth was there. This implies only two premolars were
retained on an adult lower jaw half. This is the count of all cimolods excepting for those
who went down to just one. The p4 tooth, the only one present, isn't cimolod although
nor is it typically plagi. It happens to be intermediate. Also, the alveolus for p3 is
larger than would be expected for a cimolod p3. At most, they had pathetic, single-rooted
pegs there. While being reduced in size, it's not been degraded to that sort of extent.
Details like these had to have occurred in the transition from plagis to cimolods.
Affinities
Not being a cimolod, excepting for several ancient Middle Jurassic multis, presently
suffices for a multi to be termed a "plagiaulacidan". While unsatisfactory, that's still
the best that can be done. Congrats, Tedoribaatar, you're a plagi. That then leaves
three realistic options for a familial assignment. You could leave the matter open until
more information is available, shoehorn it into an already established family or, should
that seem inconceivable, attempt to produce a diagnosis for a new family. However, that
would require a useful diagnosis. Establishing a new family for a single fragment may be
fun for some. Its utility, though, would be very limited and, if that changes due to new
information, it could still be done later.
A reduced p3 is a trait of eobaats and Arginbaatar. The latter has a more arcuate
p4. The new genus is more in line with Eobaataridae, and the number of serrations is also
within their known range. "Tedoribaatar reini is tentatively considered as a
member of Eobaataridae and the most derived "plagiaulacidan"
multituberculate yet discovered." I take that as effectively meaning: the closest known
plagi relative of cimolods.
Size
Only the p4 premolar is known. Length 3.7mm (p.385).
Tedoribaatar is a close match in size with Eobaatar and Hakusanobaatar.
Sinobaatar, a Chinese family member, is a bit larger but not by all that much. All
that trio have reduced p3 teeth as well. However, Tedori is the only known plagi with
(apparently) a single-rooted version and (apparently) only two lower premolars per side
(p.388). There are, however, several relatives that have so far neglected to provide such
premolar details.
Holotype
The type fossil, fondly known as SBEI 1570, works for a living at the Shiramine Institute
of Paleontology, Hakusan. The specific name conjures up the memory of a German geographer,
Herr Dr Johannes Justus Rein. Twas he, no less, who collected the first known remains of
Cretaceous plants from the locality as reported in 1877. Reference: Kusuhashi N (2208), Early Cretaceous multituberculate mammals
from the Kuwajima Formation (Tetori Group), central Japan, Acta Palaeontologica Polonica,
53(3), p.379-390.
Other
reports:
Help:
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.
Ktdykes@arcor.de
With further thanks due to:
Bibliography:
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