BASAL CYNODONTS, an internet directory: |
PLEASE NOTE: THIS PROJECT IS NOT SCIENTIFIC. IT IS A HOBBY.
"I was looking for information on an old animal and found this lot. What is this
project?"
It's got lots of information on old animals. For a short bit of background information, see
here.
Cynodontia Owen, 1861
Like all mammals I'm also a member of a wider group called
Eucynodontia, the main focus of my paleo-interests.
Together with some more basal relatives, we make up
Cynodontia; the last surviving and most successful of synapsid lineages. We've so far
managed to breed our way through over 250 million years and three mass extinctions. The
libido of Tyrannosaurus was wiped out with the Cretaceous-Tertiary transition, but
the eco-turbulence did nothing to reduce cynodont virility. It seems to have stimulated a
boost beyond the wildest hopes of users of some products, (eg. Viagra or
NIAGRA).
This directory concerns basal cynodonts from the Upper Permian and Lower Triassic. It's
subdivided into three sections: Permian cynodonts, Galesauridae and Thrinaxodontidae. The
first contains the most distant of my cynodont relatives, whereas
Thrinaxodon was the more closely related taxon.
Synapsids
Before briefly mentioning some features of cynodont anatomy, some the group's prehistory
might be of interest. That story begun during the Upper Carboniferous. By about 315
million years ago, two main lines of non-amphibian, terrestrial
vertebrates had emerged; reptiles and synapsids
(sometimes termed "mammal-like reptiles"). The early wave synapsids,
'pelycosaurs', went on to dominate the equatorial
land faunas of the Lower Permian. By the early stages of the Upper Permian, (about 270 mya),
pelys were being succeeded by advanced synapsids called
therapsids. These animals radiated relatively quickly, and this may be largely because
they were able to colonise a wider variety of habitats. As far as is known, the pelys were
restricted to the equatorial zone. Therapsids have been found much further to the north and
south.
Therapsid lines
Therapsids came in a great variety of shapes and sizes; small insectivores to seriously
large herbivores. They dominated the Upper Permian landscapes. The most 'pelycosaur'-like
representatives are biarmosuchians. There were also
large animals called dinocephalians, which were common
for a while. However, they disappear from the fossil record before the end of the Permian.
A highly successful group of herbivores were the anomodontidans, most of which were
dicynodonts. They survived until at least 230 million
years ago. A specimen from Australia has been astonishingly and reasonably interpreted as
a Lower Cretaceous dicynodont. If correct, than relict populations persisted for 110
million years longer than previously realised. Permian forms would have been hounded by
the carnivorous gorgonopsians such as Lycaenops.
Gorgonops ranged in size from small dog formats to more than tiger-big.
Therocephalians were also meateaters, but generally
of modest sizes. The earlier versions were reminiscent of gorgonopsians, whereas some of
the later members have similarities with cynodonts; the final synapsid lineage to appear,
late in the Permian. In particular, the baurioideans show indications of a high metabolic
rate and presumably endothermy ('warm bloodedness'). The ancestors of cynodonts may have
been therocephalians. A few forms are known from the Lower Triassic. Only dicynodonts and
cynodonts persisted for longer.
Cynodonts
Kemp, 2005 provides an outline of cynodont anatomy on page 60. The group contains animals
which are clearly related with each other, and several dozen significant characteristics
(synapomorphies) have been cited. Among the easiest
points to grasp are:
# A deepening of the cheek bone (zygomatic arch) and
developments on the dentary, both of which are associated
with powerful adductor musculature;
# A reduction in size of the quadrate and
articular bones, the components of the primary jaw joint;
# A differentiation of the teeth into unserrated incisors,
canines and postcanines.
The front postcanines are more simply built than the rear ones;
# A secondary bony palate at the roof of the mouth, with this being fully ossified beyond
the basal members;
# A clear demarcation of the chest into breast (thoracic) and stomach
(lumbar) regions.
Most of these features have significant implications for enhanced efficiency in utilising
food and oxygen; more effective eating and breathing. Cynodonts have raised metabolic
rates. |
A. Permian cynodonts
B. Galesauridae
C. Thrinaxodontidae
| These taxa are the earliest and most basal known members of
Cynodontia, Owen 1861. There are two families involved. Dviniidae is known from Russia
whereas the procynosuchids have been found in Africa and Europe. In at least one case, a
Permian representative is referrable to Galesauridae.
Consequently, that's where Cynosaurus may be visited.
Similarly, Nanocynodon may be a Permian
thrinaxodontid or galesaurid.
Genera: Aleurodraco (= Procynosuchus),
Charassognathus, Cyrbasiodon (= Procynosuchus),
Dvinia, Galecranium
(= Procynosuchus), Galeophrys (= Procynosuchus), Leavachia
(= Procynosuchus), Madysaurus, Mygalesaurus
(= Procynosuchus and/or Cynosaurus), Nanictosuchus (perhaps = Procynosuchus),
Paracynosuchus (= Procynosuchus), Nanocynodon,
Parathrinaxodon (=Procynosuchus), Permocynodon (= Dvinia),
Procynosuchus, Proticynodon
(= Procynosuchus), Scalopocynodon (= Procynosuchus),
Suphedestes (= Procynosuchus), Suphedocynodon (= Procynosuchus),
Uralocynodon, other reports
Time-Line:
Triassic: Madysaurus
Upper Permian: Charassognathus, Divinia, Nanocynodon,
Procynosuchus, Uralocynodon |
| Genus: Charassognathus
Botha J, Abdala F & Smith R, 2007
'notch jaw'
Remarks: This is presently the oldest known cynodont in the world by a couple of
million years or so. Remains include a crushed skull (length of about 5cm), partial
lower jaws and bits of skeleton including a leg. At least it had one left to stand
on.
Of movies and music
The producer responsible for the fossil record doesn't generally display the kind of
instincts required for making exciting cowboy films. For example, in the latter,
should the baddies be about to blow their way into the safe of the First National
Bank, then the audience will have its anticipation sharpened with an explicit study
of the burning fuse. The camera follows the sparks and smoke along the trail of
gun powder or up the string to the dynamite. The cinema viewer has time to duck for
safety behind the lady with the haystack hair-do sitting in the row in front and
stuff popcorn in their ears -should they so wish, and BOOM! Then the smoke clears,
the remains of the safe are thoroughly insecure, and neat bundles of freshly washed
and ironed bank notes are ready to be grabbed. That's the way to do it.
The fossil record producer, in contrast, can't generally be bothered with the fuse.
"You want the latest sound? Get on in and groove on down. Guys and girls, give a
load scream of applause. It's the Upper Permian cynodonts!" They charge onto the
stage from this side and that and, quite suddenly, you find you've got half-a-dozen
of them banging out Rock and Roll. You had hoped for a soloist singing something
new, but no. They've sent on Procynosuchus,
Dvinia and all their Comets. It'd be something if
they all played the same song, but no. They're from various families, cynodont
radiation must've happened earlier, and the producer forgot to press the record
button yet again. The usual ration of frust.
Until now the cynodont rock group were first known to be strutting their stuff
during the last couple of million years of the Upper Permian (according to Botha et
Al, 2007 at least). Three broadly South African and three (update: four) genera
occur more or less in the same chunk of time represented by the Dicynodon
Assemblage Zone in Karoo. The slight exceptions are provided by Procynosuchus.
While it appears for most of that zone, it's also been found in the top part of the
proceeding Cistecephalus AZ (and geographically wider afield in Africa, Germany
and, apparently, Russia). Effectively, that was a band of cynodonts with no sign of
anything like grandparents. They could, perhaps, have all been delivered to gooseberry
bushes by storks, but several doubts make such a hypothesis problematic; for example,
the lack of gooseberry bushes and storks. And it's not even as if all these
critters were doing similar jobs. Procynosuchus has been publicly accused
of semi-aquatic tendencies, the teeth of Dvinia are peculiarly specialised
for some peculiar purpose or other, and Nanictosaurus
seems to be more of a general, terrestrial mugger of the small in the future
traditions of progalesaurids and
Thrinaxodon. (Presently, I'm perhaps unjustly
treating the latter as being a synonym of Procynosuchus.) There were no
scenes showing earlier cynodont sexual activity, and this is something else a
serious film director wouldn't neglect.
However, now there's Charassognathus. |
| Species: | Charassognathus gracilis Botha J, Abdala F
& Smith R, 2007 |
| Place: | Karoo Basin |
| Country: | South Africa |
| Age: | Upper Permian |
| Remarks: | The following, and the above even less formal
musings, are based upon my reading of Botha, Abdala & Smith, 2007. Thanks are due
to the generous supplier. Before continuing, I've heard that the ages of Russian
Permian cynodonts are presently less than certain. Localities regarded in this
study as being uppermost Upper Permian are accused, by other authors, of having older
ages; uppermost 'Middle' Permian. Should that be correct, then some of these notes
might require revision. However, for the here and now, I'm assuming that Botha &
Co are infallible.
A bit further back down the road
A road in South Africa's Western Cape Province leads us a bit deeper into cynodont
history than was previously available. The R353 runs through the Teekloof Pass
between the towns of Leeu Gemka and Fraserburg, and the cutting it follows takes us
deeper than the Cistephalus Assemblage Zone, and into the underlying
Tropidostroma AZ. Among at least 16 fossil localities of this age in a
relatively small area, one revealed remains of a small cynodont corpse. It's the
earliest cynodont by something like 1.5 million years, and it's also more
basal than any so far found. There's no longer any
need to get into heated arguments with your family and neighbours concerning that
controversy, are dviniids or procynosuchids the most primitive cynodonts around.
Charassognathus has loads of charisma, but it most both families appear into
relative sophisticates.
Introducing 'notch jaw'
'Notch jaw' is what Charassognathus means, and the reasoning behind its
selection is instructive. One way of endeavouring to suggest why requires thinking
back to those skeletons you stuck up as decorations last Halloween. The lower jaw
in extant mammals is all dentary, but that didn't
apply for non-mammalian cynodonts or, indeed, early mammals. Nevertheless, the
plastic skeleton had a kind of upwards lump in the end of its jaw behind the tooth
row. That's its coronoid process. It's rather useful for anchoring chewing muscles
on, and also brings us painlessly to the right area of the body. Charassognathus
has got a similar upwards lump but, in this version, there's a notch on the back at
the foot of the thing; an indentation roughly level in height with the lower tooth
row. That's the notch, it's on the jaw, and so the name's Charassognathus.
A similar notch occurs for Procynosuchus and
Dvinia (p.478). It's a badge of membership for early
cynodonts. A bit later we'll have a short natter about why it was there.
Teeth
The known dental formula per side for this individual is: (uppers): ?4
incisors, 1 canine and
eight postcanines; (lowers): 3, 1 and some number
or other respectively. In contrast to the two other cynodonts just mentioned, there
are no signs of any somewhat odd sounding teeth called precanines. These also don't
occur on further derived cynodonts. My intuition would expect them to be there but,
instead, there's a bit of a gap between the incisors and canine. The front group of
postcanines and simple, dull teeth with but a single tall cusp each. Things get a
bit more expressive further back along the line, as the main cusps tilt slightly to
the rear, and there are small accessory cusps both in front and behind.
Grave sweet grave
This individual was found in its last grave rather than its living room. It was in
the upper half of a thick mass of largely mudrock strata deposited by the generosity
of rivers and lakes. The geology indicates large rivers roamed the area; Mississippi
sort of sizes. Sometimes, they were overfuelled and overflowed, and such events
provided much of the mud. The more detailed picture, however, suggests 'notch jaw'
ended up in a pond (p.480). That would've been an odd choice of home but, given the
presence of various bones including an articulated leg, it's not likely such a small
animal had been transported over much of a distance. Such journeys are destructive.
And, roughly, where is this grave?
We're talking in terms of the southwestern part of South Africa. Should your atlas
not indicate the position of Cape Town, then you're either looking at the wrong page
or it's complete rubbish. About 300 kilometres somewhat northwest of there is the
town of Fraserburg. That's close enough to qualify as roughly right.
The age is based upon the vertebrate company
found nearby. As this includes Tropidostoma microtrema, a
dicynodont, it happens to be a good indication
that these fossils are from the Tropidostoma Assemblage Zone. Easily the most
numerous of these herbivore 'cousins' is Diictodon, and further dicynodont
companionship is provided by Oudenodon, Emydops and Pristerodon.
Nature has been far less generous with bodies of meat-eating bullies, but they tend
to be much scarcer when alive. It doesn't take all too many to add excitement to
the lives of plant-eaters; two gorgonopsians, a
therocephalian a yet to be described
burnetiamorph and the new cynodont. Further clues are provided by absentees although,
taken alone, this wouldn't necessarily be informative of anything other than the
appearance of absence. However, this factor isn't alone. Index
taxa for the Tropidostoma AZ are present, and
those from the zones both above and below haven't been found.
A squashed head
The skull has been placed in some kind of natural vice, and this squashed it from
the sides. Its snout is 23mm long as opposed to 26 for the rest of the head. As
the snout's less than half the total, this is a bit unusual. It's longer for other
Permian cynodonts and their relatives among the therocephalians.
A bone called the septomaxilla has a facial
process described as "anteroposteriorly wide". This condition's found in some
therocephalians but not other cynodonts. The probable incisor count, 4 above and 3
below -not completely certain for the uppers due to part of the bone having got lost-
is in line with the majority of South African Permian cynodonts. In this case, the
canines aren't accompanied by precanines. Instead,
there's a diastema, and the space that provides
upstairs is utilized to house the tip of the lower tooth.
As well as a goodly sized canine, the maxilla plays
host to 7 postcanines. A space (and an
alveolus on the right jaw) presumably indicate an
original eighth. The basic form of these teeth is mentioned above, but it's not yet
been stated that the main cusps lose height going backwards along the row.
The authors are cultured hosts, and naturally provide a guided tour of skull
architecture in the paper. They discuss parietals,
nasals and all kinds of other-als, and are only too
happy to assure the reader, that the frontal plays
no role in forming the edge of the orbit. For the
slightly curious tourist, the main story involves a suite of cynodont traits and
not therocephalian ones.
Affinities
Such traits, and more, successfully fill up the membership application form for
Cynodontia. An analysis of 18 theriodonts (ten
cynodonts, seven therocephalians and one gorgonopsian) and 59 characters of the skull
and teeth was undertaken. According to the results, Charassognathus "is the
most basal known cynodont" (p.484). It's followed by
a clade involving Procynosuchus and Dvinia and that, in turn, by
Epicynodontia; in effect, every other known cynodont including me.
All the better to bite you with, Red Riding Hood
The aforementioned notch at the base of the coronoid process is a feature held in
common with Procynosuchus and Dvinia. It was functional, not
decorative, so what's it for? It appears to be involved with: "the invasion of
adductor mandibulae externus musculature on the lateral surface of the
dentary." This concerns the realignment and
redevelopment of muscles for stronger biting and, later, for chewing. It represents
an early stage of that story.
The slaughtering ground
Page 481 provides a listing of the body count from 16 outcrops of vertebrate
yielding rocks from this particular Assemblage Zone, and these are spread across an
area with an east-west extent of about 6 kilometres. I'm now going to attempt to
count the various corpses mentioned, or bits of corpses. While I can't guarantee
you can count upon my counting -these are 'unofficial' figures, I surely can't get
things all that much wrong. Excuse me while I take my shoes and socks off, and for
the removal of any other items of clothing should we get past 20. I know a body
part I can use for 21 but, after that, things could get tricky. 1, 2, 3, 4...
Ten hours later
Ready! I'm now going to tabulate my 'unofficial' figures. Totals aren't given in
the paper, and they weren't of obvious relevance to the subject.
|
Trevor's dodgy corpse count |
|
| Affinities |
Taxon |
Number |
| Dicynodontia |
Diictodon galeops |
87 |
| Dicynodontia |
Dicynodontia |
10 |
| Dicynodontia |
Emydrops minor |
3 |
| Dicynodontia |
Pristerodon mackayi |
4 |
| Dicynodontia |
Oudenodon baini |
3 |
| Dicynodontia |
Tropidostoma microtrema |
8 |
| Gorgonopsia |
Lycaenops ornatus |
1 |
| Gorgonopsia |
Cynosaurus longiceps |
1 |
| Burnetiamorpha |
Burnetiamorpha |
1 |
| Therocephalia |
Ictidosuchoides longiceps |
2 |
| Cynodontia |
Charassognathus gracilis |
1 |
| Provisional total |
|
121 |
Caution: It shouldn't be assumed that this list is necessarily complete or
that I've got my sums correct.
I've come to the figure of 121 identified bodies, and an impressive 72% are from a
single species. This could provoke a sensible question. If this count is anything
like representative, then why on Earth is this the Tropidostoma Assemblage
Zone? There aren't enough of those to form a football team.
On the face of it, Diictodon is ridiculously common. However, maybe the killing
mechanisms or undertakers had an unusual liking for the genus in this place. I've
no way of knowing if the figures are a reasonably accurate reflection of the living
fauna. But there's a more practical problem. Diictodon was a successful
genus for millions of years. While it's certainly common (and that's good for
useful index taxa), it's too bloody common for too bloody long (bad). Members kept
breeding until the end of the Permian, and that makes them fairly useless as more
refined indicators of time. Although less than 10% of this body heap comes from
Tropidostoma, it still made enough babies to be both informative and
findable. It's proven itself useful, and that's why it was granted the deeds to
an Assemblage Zone.
Holotype
SAM-PK-K 10369 is a squashed skull, lower jaws and other bits and pieces. It now
lies in state at Iziko, South African Museum, Cape Town. The specific name honours
the animal's delicacy. |
| Reference: | Botha et al (2007), The oldest cynodont: new clues on
the origin and diversification of the Cynodontia, Zoological Journal of the
Linnean Society, 149, p.477-492. |
| Genus: Dvinia Amalitskii VP, 1922
'from Dvinia'
Aka: Permocynodon Woodward, 1932
Family: Dviniidae Remarks: The family is presently restricted to a single species
represented by three specimens from the same locality (Battail & Surkov, 2000,
p.113). One of these is a complete skull with lower jaws, and it achieves a length
of 12cm. |
| Species: | Dvinia prima Amalitskii VP, 1922 |
| Aka: | Permocynodon sushkini Woodward, 1932 |
| Place: | Sokolki, Malaya Severnaya Dvina River, Arkhangelsk
Region |
| Country: | Russia |
| Age: | Tatarian, Upper Permian |
| Remarks: | The following is based largely on Kemp, 2005 (p.62).
As with Procynosuchus, the coronoid process of the
dentary is relatively small by cynodont standards and the
postdentary bones are relatively large. However, they're respectively large and small in
comparison to non-cynodonts. Aspects of the braincase are more
basal than for Procynosuchus.
In fairness to dvinian dignity, its postcanine teeth are
more complex. The posterior group of both uppers and lowers are fairly broad and something
like circular in occlusal outline. These crowns are
blessed with a ring of cuspules around the margins.
The skull size suggests an animal of half-a-metre or so, as with Procyno. An omnivorous (or
even herbivorous) diet has been suggested. The teeth don't provide obvious pointers to
tastes.
Additional notes
Battail & Surkov, 2000 contains a brief introduction on p.113. There could be
some overlap with the comments above.
This critter was an early, primitive cynodont from the days when we 'dog teeth'-ers
were just starting out. It was resurrected from its ancient grave by a pioneering
Polish paleontologist, Professor Amalitskii. With much help from his friends, he
established the genus posthumously.
As they were attending to a summary of all Permo-Triassic Russian
therapsids, the authors of the 2000 study provide
only a brief introduction. The sketch on page 114 shows a very toothy approach to
living, and especially so in front of the impressive upper
canine. While 13 postcanines per side is fairly extravagant in comparison to
me, it's not an outrageous figure for non-mammalian cynodonts. Dvinia,
however, packed in six incisors and, additionally, a
vestigial precanine tooth; old-fashioned for a cynodont. These teeth are
necessarily crowded together in what is a comparatively narrow snout. But, as the
basal procynosuchids also came supplied with half-a-dozen
incisors and such precanines, this behaviour was normal enough for the time of
Earth.
Holotypes
The type fossil, PIN 2005/2465, is the front of a skull in the collection of the
Paleontological Institute, Moscow. A more complete skull, PIN 2005/2469, was
designated the holotype of Permocynodon sushkuni. The single locality is
located in the area of Kotlas.
Name that author
The author's name is sometimes also given as Amalitzky. This is the spelling given
in the description, so it might be thought he knew. However, as the professor was
already dead, he presumably knew nothing whatsoever at the time. |
| References: | Amalitskii VP (1922), Diagnoses of new forms of
vertebrates and plants from the Upper Permian of North Dvina, Izvezstiya AN SSSR,
VI Seriya, 16, p.329-340. |
| Woodward AS (1932), Zittel's textbook of Paleontology, Volume
2, London, Macmillan, 464pp. |
| Genus: Madysaurus
Tatarinov LP, 2005
'Mady reptile'
This genus obviously doesn't belong in a section for Permian cynodonts, but I'm not
yet sure where else to put it. |
| Species: | Madysaurus sharovi Tatarinov LP, 2005 |
| Place: | Magygen Formation |
| Country: | Kyrgyzstan |
| Age: | Triassic |
| Remarks: | Looking at the abstract of the publication
leads me to conclude this probably is the most appropriate directory, despite the
animal being from the Triassic. It's said to belong to: "aberrant descendants of
the procynosuchian cynodont lineage." Details of the skull include wide
parietal bones, no sagittal crest and an upper
orbital rim involving bones called the postfrontal,
prefrontal and postorbital. As for the teeth, the upper jaw has five
incisors per side and, at the most, eight
postcanines. The lower jaw bears at least three
incisors.
Regardless of the name, this is a synapsid, as you
are, and not a reptile. |
| Reference: | Tatarinov (2005), A new cynodont (Reptilia, Theriodontia)
from the Magygen Formation (Triassic) of Fergana, Kyrgyzstan, Paleontological Journal,
39(2), p.192-198. |
| Genus: Nanocynodon
Tatarinov LP, 1968
'small dog tooth'
Family: ?Procynosuchidae |
| Species: | Nanocynodon seductus Tatarinov, 1968 |
| Place: | Kirov |
| Country: | Russia |
| Age: | Tatarian, Upper Permian |
| Remarks: | The following is based upon my
reading of Battail & Surkov, 2000 (p.114) and thanks are due to the supplier.
Some fossils are found on the ground, but some excavation is commonly necessary for
others. Digging down to the Nanocynodon grave to check for any more remains
would've been a challenge, even for the most dedicated of spade wielders. The hole
required, should anybody be feeling ambitions, will have to go down more than 250
foot.
The owner was tiny with at least ten postcanines
per side. It was only a kid when it died, and its systematic affinities are unclear.
I'm presently assuming the revised view is correct, and that indicates a procynosuchid.
This certainly appears more likely in terms of time, but that doesn't necessarily
mean it's the correct option. The original author was more tempted by links with
the further derived (and otherwise later) galesaurids
(including Thrinaxodon). Battail & Surkov were
more inclined to that view. Of course, both possibilities could be wrong, but it's
at least a young cynodont.
Postcanines
These teeth are narrow and have an array of small cusps on a
cingulum to the buccal side (p.115). They're
sectorial teeth as are the equivalents for galesaurids; that effectively means
slicing teeth for dealing with meat. Should anybody be planning to dig down to this
particular graveyard, then I'm sure further specimens would be more than welcome.
250 foot (or 'feet' should you prefer, but that ain't 'ow we speak in Dorset)
indicates 85 metres below the surface.
Holotype
The type fossil, PIN 2415/1, is a partial lower right jaw in the Paleontological
Institute, Moscow. |
| Reference: | Tatarinov (1968), [New theriodonts from the Upper
Permian of the USSR], p.32-45 in [Upper Palaeozoic and Mesozoic amphibians and
reptiles of the USSR], Moscow, Nauka, [Russian language]. |
| Genus: Procynosuchus
Broom, 1937
'before dog crocodile'
Aka: Aleurodraco Broom & Robinson, 1948; Cyrbasiodon Broom, 1931;
Galecranium Broom, 1948; Galeophrys Broom, 1948; Leavachia Broom, 1948;
Mygalesaurus Broom 1942; Nanictosuchus Broom, 1940; Paracynosuchus
Broom, 1940; Parathrinaxodon Parrington, 1936; Protocynodon
Broom, 1949; Scalopocynodon Brink, 1961; Suphedestes Broom 1949;
Suphedocynodon Brink, 1951
Family: Procynosuchidae
Remarks: Yes, that would appear to be more names than strictly necessary. Confusion
can result from poor preservation, different biological ages and various other
reasons. As I've still got a couple of studies on this genus to read through at
some point, the entry below could end up challenging War and Peace for brevity.
A matter of names
For those who know the rules of zoological nomenclature, there may be an apparent oddity
requiring explanation, and much of the answer is provided by Kammerer & Abdala, 2009 and
thanks are due to Fernando for forwarding a copy. Two of the synonyms for this genus
predate the name Procynosuchus and, normally, the oldest would have priority.
That would lead to the poor critter being called Cyrbasiodon Broom, 1931.
The 2009 paper just cited is an appeal to sanity, should that term be appropriate for
matters of vertebrate paleontology. It's a plea to the International Commission on
Zoological Nomenclature to excercize their right, if justifiable, to overrule the usual
practice and grant Procynosuchus priority as being the valid name. A number of
supporting reasons are given.
# Procynosuchus is used in dozens and dozens and dozens of studies. Both C.
and Parathrinaxodon would struggle to qualify as being famous enough to merit the
term 'obscure'.
# Procyn often gets to feature in books for the general public and textbooks for students.
Neither of the older names have managed that.
# There are lots of museums around the world with exhibits labelled as Procyn.
# "Conversely, the genera Cyrbasiodon and Parathrinaxodon are known by only
a small group of non-mammalian cynodont taxonomists", (p.66). As I know them as well and
I'm not any sort of taxonomist, that's not strictly accurate! However, it's at least not
wildly far from the truth.
# Descriptions of specimens referred to Procyn have been unusually thorough thanks to
excellently preserved specimens.
I'm working on the assumption that the ICZN will let continuity and sense prevail.
Thus, Procynosuchus gets priority on this directory. |
| Species: | Procynosuchus delaharpeae Broom, 1937 |
| Aka: | Aleurodraco microps Broom & Robinoson, 1948;
Cyrbasiodon boycei Broom, 1931; C. vladimiriensis Tatarinov, 1987;
Galecranium liorhynchus Broom, 1948; Galeophrys kitchingi Broom, 1948;
Leavachia duvenhagei Broom, 1948; L. gracilis Brink & Kitching,
1951; L. microps Brink & Kitching, 1951; Mygalesaurus platceps
Broom, 1942; Nanictosuchus melinodon Broom, 1940; Paracynosuchus rubidgei
Broom, 1940; Parathrinaxodon proops Parrington, 1936, Procynosuchus
rubidgei Broom, 1938; Protocynodon pricei Broom, 1949; Scalopocynodon
gracilis Brink, 1961; Suphedestes polydon Broom, 1949; Suphedocynodon
gymnoternporalis Brink, 1951 |
| Place: | Dicynodon Assemblage Zone,
Karoo & Upper Kawinga Formation & Hessen |
| Country: | South Africa, Zambia & Germany & Russia |
| Age: | Upper Permian |
| Remarks: | The following is based upon my reading of Kemp,
2005.
Procynosuchus is a basal cynodont represented by
several skulls from South Africa, a nearly complete skeleton from Zambia and further
fossils including a specimen from Germany, (p.60). Skull lengths reach 14 centimetres and
bodies 40cm. It approaches mammalian anatomy in a number
of ways.
Mammalian traits
The postcanines are differentiated into two varieties.
The first five are relatively simple, with one inwardly curving cusp. The following eight
are more sophisticated, (p.61), as they feature a row of small, distinct cusples on the
inner base. There's no suggestion of occlusion between uppers and lowers. Modifications of
the skull and jaws show the chewing musculature was in advance of the capabilities of
therocephalian therapsids. For example, the coronoid process of the
dentary is relatively wide so as to provide some space for adductor muscles. The
dentary is thus larger and the postdentary bones have been reduced in size. The secondary
palate at the roof of the mouth is also better pronounced, but extensions of the
maxillae and palatal bones didn't reach their opposite
colleagues at the midpoint. The resultant gap was probably bridged by soft tissue instead
of bone.
There is differentiation of the spine into breast and lumbar regions, but the lower spine
is still well ribbed. Hips and shoulders show few typically cynodont characteristics.
Getting in the swim
The skeleton from Zambia suggests a semiaquatic animal analogous perhaps to a small otter.
The lumbar vertebrae would have allowed extensive sidewards
movements. Along with adaptations in the relatively long tail, this would have served well
for swimming.
Perhaps distinct
Leavachia from South Africa is also known from postcranial elements. They were
sketchily described but lack the semi-aquatic specialisations. It was a more terrestrially
inclined animal, and could belong to a distinct genus.
Unclear to me
Cyrbasiodon vladimiriensis Tatarinov, 2004 is some kind of
therapsid from the Upper Permian of Russia. I don't
know for sure whether this species is of relevance to the same generic name reported
to be synonymous with Procynosuchus. I'm grateful to Palaeos for the impressive
nomenclatural collection.
Update 14.7.2009: Kammerer & Abdala (2009) confirms the specimen known as C.
vlad. was indeed transferred to the genus of Procynosuchus. It's a fragment
of upper jaw with two postcanine teeth.
Emerging clarity
Botha et al, 2007 have been telling tales. They accuse Tatarinov of synonymizing
Cyrbasiodon with Procynosuchus in 2004. As a consequence, the genus
has spread to Russia.
The artist formerly known as Parathrinaxodon
The following section's based upon my reading of Abdala & Allinson, 2005, and thanks
go to the supplier. The various exotic names may confuse some people. Bear in mind
that Parathrinaxodon is a synonym of Procynosuchus, and this applies
even when I use the first name below.
This individual is known from a parital skull born in, or near, Tanzania druring
the latter stages of the Upper Permian. Presumably, the rest of the animal was
delivered with it, but all those bits dropped off. From the middle to the rear of
the postcanine row, the upper teeth have an oval
outline (p.45). There's a large main cusp with very modest cuspule partners, one
each fore and aft. This dental architecture accords with the similarly aged
Procynosuchus. Differences were cited as being a fully ossified secondary
palate (as opposed to only a partially ossified one), and an opening by the
maxilla bone. However, pressure and time had been
ungentle. The fossil has been subject to breakage and deformation. Rather than having
a fully boned secondary palate, processes of the maxilla and palatine got bashed a
bit out of position, and the apparent opening (previously grandized by being called
a vomerine fossa) resulted from this displacement. The overall similarity with
Procyno is due to the Procyno identities of its mummy and daddy.
Normally, as the Parathrinaxodon taxon was
actually established first, by Parrington in 1936, it would sweep Broom's 1937
Procynosuchus out of usage. (Apologies are offered for that unfortunate
phraseology, and this will very possibly occur again.) However, as
Procyno has enjoyed far more attention over the years, Abdala & Allinson brush
that aside by citing artcle 23, section 9 of the rules governing zoological
nomenclature. That provision allows long-established names to remain valid.
This individual was found in the Kawanga fauna of Tanzania, and that fauna shows
most similarity with with the former wildlife of South Africa; namely the
Tropidostoma, Cistecephalus and Dicynodon Assemblage Zones.
Upper Permian cynodonts
Ten Permian cynodont species were recognized at the time of publication, but six of
them were disputed in terms of validity, with one of those being this species. Finds
have been made in South Africa, Zambia, Tanzania, European Russia and Germany.
According to Parrington, in 1936, Parathrinaxodon shared most similarities
with Dvinia and Thrinaxodon,
as the name he selected suggests. Subsequently, other researchers argued for
affinities with Procynosuchidae or Galesauridae.
Size
The skull is incomplete but nigh on its entire length is represented. While the
snout's mostly present the cheek areas have gone. Para's head is about 13cm long, and
only 4.5 of those are provided by the snout. It's fairly large for a Procyno
individual but not a giant. A specimen in the Rubidge collection manages 1.4cm
more (p.47).
Upper teeth
The right jaw retains four 'incisors' but, as the
front of the snout's absent, there could have been a couple more in life. Two of
the team may actually be housed in the maxilla bone.
However, as the join between that and the premaxilla
can't be made out for sure, certainty isn't possible as to whether this pair
qualify for the status of precanines; non-incisors still sported by many
basal cynodonts.
The postcanines number ten (left) and eleven
(right). The first and third are the simplest in build, with main cusps accompanied
by small accessories in front and behind. These teeth widen and become more complex
further back, in that a cingulum occurs on the
lingual side, and this bears more cusps. An isolated
crown, possibly the sixth, sportss one such cusp at the front of the cingulum and two
to the rear.
A psychotic cynodont
For a variety of reasons, this critter was originally told to go and play with the
Russian speaking Dvinia. They both had small snouts, eyes set to the front,
similar numbers of teeth and somewhat similar postcanine morphology (p.48). A main
cusp with small helpers fore and aft, combined with a lingual cingulum, is a combination
also found for the later Thrinaxodon. This was taken as support for
affiliation. Also included was Cyrbasiodon boycei. Generally, that was
considered to be a therocephalian rather than
a cynodont in 1936, but it's now regarded as a procynosuchid; indeed, another
synonym of Procyno. delaharpeae. All this was a year prior to the description
of Procynosuchus, and that naturally posed an insurmountable problem for a
comparison.
Parrington was working without hindsight, and Parathrinaxodon was moaning
about his verdict. The animal was furious at being told to get next to its distant
Triassic cousin a number of times removed and, still complaining, it was told to
pull itself together before being shut away in an unclosed case, metaphorically
speaking.
Perhaps attracted by the moans, various doctors popped in to see the patient over
the years. Several of them ummed and ahhed in the direction of Procynosuchidae, but
its smiles of pleasure failed to move others from presenting diagnoses marked
Galesauridae (p.49). 'It has no interpterygoid vacuity, is totally deficient in
the possession of precanines, and is encumbered with a completely ossified secondary
palate,' ran one opinion. 'And besides, no decent lingual cingulum on the postcanines
is a mark of galesaurids.' While that point is true enough, it's not exclusive to
that family.
Disturbed and distorted
In as far as they're well enough preserved to be compared, the postcanines are
consistent with Procynosuchus, and clearly distinct from Dvinia.
Furthermore, the oval outline and smallness of the accessory cusps are contrasts to
Thrinaxodon. The numbers present are in accord as
well, and so are the length proportions of the snout compared to the skull. Other
'distinctions', an opening in the palate and its complete ossification, have been
artificially added by disturbance and repositioning of the bones. The apparent
absence of precanines is also not clear.
Kawinga fauna (p.50)
The latest psychiatric reports indicate that psychotic Parathrinaxodon actually
belongs to Procynosuchus and, hopefully, it'll be happier with this
recognition. If all goes well, it may then be able to return to its former
employment of terrorising smaller vertebrates in the Tanzanian Upper Permian. The
neighbourhood is known to be home to at least four
dicynodonts, a number of stupid and murderous
gorgonopsians, a couple of therocephalians and some kind of pareiasaur. However,
if the semi-aquatic lifestyle is correct for the genus, then it'd presumably show
a preference for fishing expeditions.
In terms of tetrapod genera, six members of this fauna are presently only known from
Kawinga whereas two-thirds, fourteen by number, also occur at various levels in the
Karoo Upper Permian of South Africa. Given the geographic proximity, that seems
none too surprising.
As well as the globetrotting Procynosuchus (Parathrinaxodon), two
dicynodonts also occur further afield(p.51). Dicynodon -possibly not a
natural taxon- has been found loitering in Scotland, China, Laos and Russia. Its
friend, Geikia, has been spotted by tourists near Elgin in Scotland.
No kidding, news of a kid
This next instalment is based upon my reading of Botha-Brink & Abdala, 2008, and thanks
are due to the supplier.
Right-minded German parents, now sadly an endangered species since the rise of Namby-Pambyism,
help their kids along the correct path of responsible conduct by lovingly scaring the
hell into them in the nursery. They read them instructive goodnight stories from a book
called
Struwwelpeter; stories designed to keep the mind active during night-time with
healthy worries about the inevitable consequences of wrong-doing. For example, should a
child be tempted by the sin of thumb-sucking, then a little tailor is sure to leap out
from behind the curtains, and remove the offending member with his sharp scissors. Should
a boy even contemplate masturbation, then reliable Struwwelpeter heightens the menace by
not mentioning such as unspeakable subject. Nevertheless, that silence speaks volumes.
Meet Sam
If only such a useful book had been available during the Upper Permian. Sam, the
cynodont, would undoubtedly have lived a longer life. Sadly, though, illiteracy was rife
at the time, and Sam received no such instructive warnings.
It's not clear how he came to such a sticky end with a flattened skull, but that
presumably had much to do with the great weight pressing down on his head over ever so
many years. However, regardless of details, this squashing did his manners no harm at
all. He never did anything naughty again, and so learnt a valuable lesson from his
misfortune. That's an important point ignored by those leftie "child-rightests" that
foolishly maintain squashed skulls are somehow detrimental to child development! Don't
listen. Trust Struwwelpeter instead.
What's also unknown is whether Sam was actually a boy. His adoptive parents at the Iziko
South African Museum in Cape Town presumably feel he was, for I can't think of any other
reason for them calling him SAM-PK-K 10138. Let's simply accept they're correct.
As well as having his obedience enhanced terminally as a relatively young pup, Sam is also
among the earliest known birds of Cynodontia. He's only the second recovered from the
Tropidostroma Assemblage Zone (p.1), and now acts as a playmate for
Charassognathus, whose final remains were born in
print in 2007. This particular zone is thought to predate all other suppliers in the
world by a bit. That detail naturally also extends the known range of this genus back in
time. Procynosuchus has now become the only Karoo cynodont to post details of its
presence in three local Assemblage Zones. That's a career of around three million
years. Until the past couple of years it had only been found in the Dicynodon AZ
as far as Karoo was concerned.
Pretty head
Having lost his head during the Permian, researchers found it again in 2002 in Western
Cape Province. It's somewhat squashed and battered but complete, and features tell-tale
signs of procynosuchid-osity. However, some features are atypical. These seem to be
indicative of Sam's childishness. An easily comprehensible one is the relatively short
length of a touch over 5.5cm. The snout (2.7cm) accounts for just under a half of it.
The widest part of the skull is in the middle of the temporal area (p.2). Crushing left
many joints between the bones as unrecognisable, although there are some exceptions. The
lower jaw is clamped firmly together with the upper, but the crowns of upper
postcanines can be clearly seen thanks to preparation
work. As is typical for early cynodonts, the secondary bony palate of the roof of the
mouth wasn't completely formed as there's a gap between the palatine bones. This also
applies for adults.
The coronoid process a jutting upwards bit of bone towards the rear of the lower jaw, and
it provides space for the attachment of biting muscles. In this instance, it's a
relatively low built feature (p.3), and the masseteric fossa occurs high up on it. This
is a primitive cynodont trait.
All the better to bite you with, my dear
For the upper teeth, and in varying stages of development, there's evidence of four left
incisors and five right ones. A
diastema separates the small, final right incisor from
the canine, and another occurs between that tooth and the
postcanines. There's no sign of strange teeth known as precanines in this mouth but,
as some things do occur for adults, this absence is a reflection of age rather than
pedigree. Sam was a pup.
The postcanines are, in as far as preservation allows certainty, tri-cusped or less.
There are eight on the left side. Of this octet, 1, 7 and 8 are all too damaged for
details to be discernable. Number 2 seems to have possessed only a single accessory
cusp placed in front of the main one. Numbers 3, 4 and 5 boastfully flaunt rear cusps
as well. Number 6, which was still engaged in erupting, is also tri-cusped. These
uppers have occlusal outlines that are circular.
Tricusped postcanines represent the original cynodont model, and are also favoured by the
other known cynodont of this age, Karoo's aforementioned Charassognathus. The
circular occlusal outline is a trait of procynosuchids. The corresponding teeth of other
ancient cynodonts range from oval to ellipses.
Age matters
The presence of those five upper incisors on the right jaw is somewhat unusual for early
cynodonts as a whole. A more typical count would be four uppers and three lowers (p.4).
However, it happens to be the norm for both procynosuchids and Dvinia
from Russia to have at least those numbers, and sometimes more. That, the build of the
postcanines and several archaic features of the skull indicate Sam is a member of
Procynosuchus: "... such as the interpterygoid vacuity, a massetaric fossa high on
the coronoid process and incomplete secondary palate...".
Protocynodon pricei
This invalid species was based upon a small skull (p.5) which, according to the text, has
a length of "approximately 5mm". As that's drastically smaller than Sam for sensible
comparison, I can only imagine that's meant to say '50mm'. As written, there wouldn't be
room for the reported five upper incisors on the right jaw, let alone anything else.
Be that as it may, this fossil was subsequently told to behave itself as Procynosuchus,
and reexamination shows -in contrast to most juveniles but as with Sam- there are no
precanines. Therefore, when dealing with such kids, the absence or presence of these
teeth is variable within the genus.
A long career
During the end days of the Permian, represented in Karoo by the Dicynodon Assemblage
Zone, Procynosuchus was the most common of cynodonts judging from numbers of
recovered specimens. This find pushes the age range back a bit further, and it's the first
instance of any local cynodont occurring in three such zones. Its geographical range is
also impressive, with home sweet homes also being found elsewhere in Africa, European
Russia and Germany.
As they almost say in the literary traditions of English football, the kid done good. And
that's the objective intended by Struuwelpeter.
Holotypes
The type fossil of Cyrbasiodon boycei is a maxilla living in the collection of the
Durban Museum, Natal. It was the only specimen referred to the genus and, as far as I'm
aware, doesn't have a catalogue number.
Parathrinaxodon proops: UMZC T.819 is a partial skull in the collection of
Cambridge University. Yes, I obviously mean the Cambridge in England, the real one.
If I'd been referring to some colonial imposter, then I would've downright said so.
It was the only specimen ever assigned to the Parathri genus, but has since absconded
to become Procynosuchus.
BP/1/226 claims to be called Aelurodracro microps, and this matter can be
discussed with it at the Bernard Price Institute, Johannesburg. While there, you
could also tackle its colleague, /591. It's under the impression that it's
Leavachia gracilis.
Those looking for sanity might prefer to try the residents of the Oxford University
Museum of Natural History. However, according to news that's just arrived from
Cambridge, they're not likely to find any within about fifty miles. Still, this
might be disputed by OUMNH TSK354; RC 5, the type fossil of Procynosuchus
delaharpeae if not by its colleague, RC 12, P. rubidgei. Also be
prepared for manic interventions from RC 72, Galeophrys kitchingi, and RC 92,
Leavachia duvenhagei.
Protocynodon pricei is BP/1/650 at Joana's Bernard Price Institute. It's a smalling
and presumably a kid.
|
| References: | Broom R (1937) (for Procynosuchus), A further
contribution to our knowledge of the fossil reptiles of the Karroo, Proceedings of
the Zoological Society of London, 107, p.299-318. |
| Broom R (1931) (for Cyrbasiodon), Notice on some new
genera of species of Karroo fossil reptiles, Records of the ALbany Museum, 4,
p.161-166. |
| Parrington FR (1936) (for Parathrinaxodon), On the
tooth replacement in theriodont reptiles, Philosophical Transactions of the Royal Society of London, B, 226, p.121-142. |
| Broom R (1948) (for Leavachia), A contribution to our
knowledge of the vertebrates of the Karroo Beds of South Africa, Transactions of the Royal
Society of Edinburgh, 61, p.577-629. |
| Broom R (1949) (for Protocynodon), New fossil reptile
genera from the Bernard Price collection, Annals of the Transvaal MUsum, 21,
p.187-194. |
| Tatarinov LP (1949) (for Cyrbasiodon vladimiriensis),
A new primitive cynodont from the Upper Permian of the southern Urals, Paleontological
Journal, 3, 103-107. |
| Genus: Uralocynodon
Tatarinov, 1987
'Ural dog tooth'
Family: Procynosuchidae |
| Species: | Uralocynodon tverdochlebovae Tatarinov, 1987 |
| Place: | Blumental 3, Orenburg Province, Southern Urals |
| Country: | Russia |
| Age: | upper Tatarian, Upper Permian |
| Remarks: | Battail & Surkov, 2000 provides some brief
information, and thanks are due to the kindly sender.
As far as is known -and that's not very far, this was a small procynosuchid with a
narrow coronoid process of the dentary (p.114).
However, as the former owner of the jaw didn't get to live for very long, it had
every right to be diminutive.
There seem to be different approaches to spelling the locality, as the above
authors actually favour Blyumental 3. I've followed another version as the name's
German in origin.
Holotype
SGU 10489/308 is a left dentary studying at Saratov State University. Presently,
it's the only known specimen. |
| Reference: | Tatarinov LP (1987), New primitive cynodont from the Late
Permian of the South Cis-Urals, Paleontol. Zh., 3, p.110– 114 (in Russian). |
| Other reports
Xxxxxxxxx
Xxxxxxxxxx |
A. Permian cynodonts
B. Galesauridae
C. Thrinaxodontidae
Galesaurids are more derived than
animals such as Dvinia and
Procynosuchus. The dentary boasts an enlarged
coronoid process at the back for anchoring muscles, (Kemp 2005, p.62); the
zygomatic arch at the cheek is both stronger and
more arched; the quadrate bone is small; and the number of
incisor teeth has been reduced, (four up and three down).
A further South African, Platycraniellus,
is also often included in the family. I'm presently following an unpublished interpretation
which sees that genus as being an aberrant
eucynodont.
An intruder
One genus, Silpheocynodon, may not belong on
this page or indeed anywhere else in particular. It was originally described as
a gomphodont cynodont, but Abdala et al, 2006
thought it more likely to be a young meat-eater of some indeterminable cynodont or
other (p.397). It's effectively invalid.
Genera: Baurocynodont (= Cynosuchus),
Bolotridon, Cromptodon,
Cynosaurus, Cynosuchus (= Cynosaurus),
Galesaurus, Glochinodon (= Galesaurus), Glochinodontoides
(= Galesaurus), Mygalesuchus (= Cynosaurus and/or Procynosuchus),
Nanictosaurus (= Cynosaurus), Notictosaurus (= Galesaurus),
Progalesaurus, Silphedocynodon;
'Tribolodon' (= Bolotridon), Other reports
Time-Line:
Lower Triassic: Bolotridon, Cromptodon, Galesaurus,
Progalesaurus, Silphedocynodon (invalid)
Upper Permian: Cynosaurus |
| Genus: Bolotridon
Aka: Tribolodon Seeley, 1894 |
| Species: | Bolotridon frerensis |
| Aka: | Tribolodon frerensis Seeley, 1894 |
| Place: | Cynognathus Assemblage Zone, Karoo |
| Country: | South Africa |
| Age: | Lower - Middle Triassic |
| Remarks: | Abdala et al, 2005 describe this as a rare
component of the fauna, (p.192). It was late for a galesaurid. The original name was
preoccupied by a fish. |
| Reference: | |
| Genus: Cromptodon
Bonaparte JF, 1972
'Crompton's tooth' |
| Species: | Cromptodon mamiferoides Bonaparte JF, 1972 |
| Aka: | C. mammiferoides |
| Place: | Rio Mendoza Formation |
| Country: | Argentina |
| Age: | Lower Triassic |
| Remarks: | Abdala & Giannini 2002, (p. 1151), point to
similarities of the teeth with a juvenile specimen of the later African
Aleodon.
Holotype
The type fossil, PVL 3858, is a tiny lower jaw with
postcanines in the collection of the Universidad Nacional de Tucumán. |
| Reference: | Bonaparte (1972), Cromptodon mamiferoides, galesauridae
de la Formación Rio Mendoza, Mendoza, Argentina (Therapsida-Cynodontia). Ameghiniana 9,
p.343-353. |
| Genus: Cynosaurus (Owen, 1876)
Schmidt KP, 1927
'dog reptile'
Aka: Baurocynodon; Cyanosaurus; Cynosuchoides Broom R, 1931;
Cynosuchus Owen R, 1876; Mygalesuchus (perhaps); Nanictosaurus Broom, 1936
Remarks: There's also a plant genus called Cynosaurus. Owen's original generic name
fell victim to preoccupation by a crocodile.
An analysis by Abdala, 2007 raises doubts about this genus being a member of
Galesauridae. It seems too basal (p.602). |
| Species: | Cynosaurus suppostus (Owen, 1876) Schmidt KP,
1927 |
| Aka: | Cynosuchus suppostus Owen R, 1876; Cynosuchoides
whaitsi Haughton, 1918; Nanictosaurus kitchingi Broom R, 1936; N. robustus Broom R,
1940; N. rubidgei Broom R |
| Place: | Dicynodon Assemblage Zone,
Karoo |
| Country: | South Africa |
| Age: | Upper Permian |
| Remarks: | This is presently the earliest and best known
galesaurid (Kemp 2005, p.62), assuming it's actually a member of that gang. The
secondary bony palate is still incomplete in this family, (p.64). In contrast to
Procynosuchus, the
postcanines have no row of distinct cuspules in attendance. There is a strong
accessory cusp behind the main cusp. It's possible their favourite food required
more force to crack into.
As mentioned by Sidor & Smith, 2004 (p.548), some South African
cynodonts have collected an impressive array of names over
the years, and these have often been bestowed on the basis of incomplete fossils or
individuals of differing ages. For example, baby animals aren't simply mini-adults as bits
of body tend to develop at different rates. Consequently, recognising and matching kids with
parents isn't always obvious. Further complications have arisen due to preoccupation of
names. Owen described a specimen as Cynosuchus in 1876 but, more than half a century
later (1927), Schmidt noticed that name had already been applied to a crocodile and suggested
Cynosaurus instead.
Holotypes
The type fossil, BMNH R1718, is a partial snout with lower jaws in the collection of the
Natural History Museum, London.
The holotype of Cynosuchus whaitsi is affectionately known as SAM-PK-4333,
and it's employed as an entertainer at Iziko, South African Museum, Cape Town.
The type of Nanictosaurus kitchingi, TM 279, inhabits the Transvaal Museum,
Pretoria.
NMQR 1633, the basis of Nanictosaurus rubidgei, can be visited at the National
Museum, Bloemfontein.
Additional notes
Nanictosaurus
Sidor & Smith also state four specimens were referred to Nanictosaurus, but they
seem to be juveniles of Cynosaurus (p.549). Remains are said to have come from the
Daptocephalus Assemblage Zone (formerly the upper part of the Cistecephalus AZ).
If that's correct, then they would predate most of this genus. (Sidor & Smith make no
mention of that.)
N. robustus was reportedly formerly referred to Procynosuchus. An attribution
of N. rubidgei to Brink & Kitching, 1953 seems to be incorrect.
Adala & Allinson, 2005 states that Nanicto is is presently the only known Upper
Permian cynodont with a fully ossified secondary palate (p.49).
Cynosuchus whaitsi
Sidor & Smith state this C. whaitsi was established by Haughton in 1918. Broom transferred
it to a seperate genus in 1931. Finally, it was synonymised away by Hopson & Kitching
in 1972. |
| References: | Owen (1876), Descriptive and illustrated catalogue of the fossil
Reptilia of South Africa in the collection of the British Museum. Printed by order of the
Trustees, London, 88pp. |
| Schmidt (1927), New reptilian generic names, Copeia, 163,
p.58-59. |
| Haughton (1918), Investigations in South African fossil
reptiles and amphibians (Part II), Some new carnivorous Therapsida, with notes upon
the brain-case in certain species, Annals of the South African Museum, 12,
p.175-215. |
| Broom (1936), On some new genera and species of karroo fossil
reptiles, with notes on some others, Annals of the Transvaal Museum, 18, p.349-386. |
| Genus: Galesaurus Owen R,
1859
'weasel reptile'
Aka: Glochinodon van Hoepen 1916; Glochinodontoides Haughton 1924;
Notictosaurus Broom & Robinson 1948
Remarks: I'm guessing at weasel. The Greek word has several meanings. |
| Species: | Galesaurus planiceps Owen R, 1859 |
| Aka: | Glochinodon detidens van Hoepen, 1916; Glochinodontoides
gracilis Haughton 1924; Notictosaurus gracilis Broom & Robinson 1948;
Notictosaurus trigonocephalus Brink & Kitching, 1951 |
| Place: | Lystrosaurus Assemblage Zone,
Karoo |
| Country: | South Africa |
| Age: | Lower Triassic |
| Remarks: | The following is based upon my reading of
Abdala et al, 2006, and thanks are due to the kindly supplier.
The death of Gale, a who-or-what-dunnit
Dr Fernando Abdala has made something of a name as a successful therapist for
psychotic therapsids. For example, in collaboration
wtih colleague Giannini, he was able to cure a patient known as Chini Quo Don who,
extradinary as it may sound, was under the delusion of possessing three distinct
personalities, all of them murderous. Intensive treatment brought about a complete
recovery of the senses, and the patient came to accept that they were but one ferocious
killer from the Middle Triassic (Chini Quo Don).
Other examples could be cited. These have resulted in a trail of renewed sanity
stretching from Argentina, through Brazil and South Africa, and up into East Africa.
However, and also in conjunction with worthy collaborators, he has also been involved
in helping to explain cases of mysterious deaths. On one occasion, in Argentina,
many dozens of corpses were found in the same small area of
Los Chanares. The local police force was entirely
baffled as none of their theories could account for all the circumstances. There
were no signs of brutality, none of caved in mine workings, and not a sniff of
members of an apocalyptic cult, all sharing a burning ambition to meet their maker
somewhat prior to the anointed appointment.
Knowing of his presence in the country, it's no great surprise to learn that the
police of Eastern Cape Province also called in Abdala & Co for assistance. A body
had been found, Gale S. Investigations had revealed nothing concerning the cause of
death, but they did uncover yet more bodies. Gale was sharing her final resting
place before the mortuary with Owenetta and Milli. Even more macabre was the
severed head of a young child. While mass murder might happen twenty times a day in
Johannesburg, the police in this rural backwater of the Karoo Basin have much less
experience with such matters. With the danger of panic spreading among local
residents, a specialist team was assembled: Abdala, Cisnoros and Smith -the
Casebusters.
The characters
Should anybody now be hoping for a conventional detective story, then that's
something like what's coming. We've got dead bodies, a shared grave, and mysterious
goings on to unravel and explain. I should, however, reveal something about the
identities of the victims. It could also be worth knowing that these deaths occurred
some while ago; roughly 245 million years. The corpses, or what remains of them,
are well preserved but not exactly fresh or still smelly. Oh, and I was fibbing
about the police.
Gale S was a
squirrel-sized, meat-eating cynodont.
Owenetta, a close acquaintance, was a smaller, gecko-like lizardy reptile,
and the stray skull belonged to a younger one of those. It might be tempting to
believe Galesaurus got angry or hungry, attempted to attack Owenetta,
but was then killed in self-defence. But that sort of thing should leave signs of
violence; bite marks, shotgun wounds or something. Neither Gale nor Owenetta
show any such things. Besides, it's unlikely that a live, ten cm lizardy thing
could've been of much nutritional interest to a small cynodont with terrible chewing
talents. A juvenile perhaps, but ten cm was too much to attempt to gulp down in one
go.
I've just realized. I forgot to properly introduce Milli. That's a small millipede
still lying on Owenetta's leg. What we've got is a small group of peacefully
dead animals, not violently killed ones. Then again, there's that severed skull...
Till death doth us keep together
This collection of corpses may appear a rum association; not the sort of group who'd
wish to spend eternity in the company of one another. Then again, I doubt they were
asked for an opinion. It's the first multi-taxon
commune to be described from the Lystrosaurus Assemblage Zone (p.507). There's
an oddity about the skeletal remains. While not complete, what's present is
articulated. This means the bones are still in their natural positions with regard
to each other. These animals kept their heads on their shoulders for far longer
than most. And easily breakable bones are still there. Gale retains the
stapes bone that was used earlier for processing
sound. These bodies must've been protected in some way from the ravages that even a
short time can inflict. They weren't thrown around by playful water, left out to
be attacked by the weather, or available for recycling by hungry scavengers.
A deathly deviation
There's a point which rewards a bit of reflection. As is fairly widely known, the
fossils of land animals, especially vertebrates,
are comparatively rare. All those born are allowed to die. The administrators of
the Earth insist upon them exercising this privilege at some time or other. But
fossilization usually requires fairly freaky conditions, and most animals like this
pair, 30cm Gale and 10cm Owenetta, don't get preserved.
If you happen to live in a town in the right parts of the world, spare a quick
thought for squirrels. These can be very common in urban areas with trees, such as
some parks and many cemeteries. Go and visit them with a bit of patience and a bag
of hazel nuts, and you'll find you can make yourself very popular. These urban
forest dwellers can thrive in hordes that natural forests wouldn't dream of
allowing. Or, if you're not in the right places for squirrels, think pigeons or
something else more appropriate. In any Western European town, you can see enough
pigeons to make even their ardentest fancier sick. We could also contemplate rats.
In Britain, it's sometimes said that there's a four-legged rat for every bi-pedal
one. A largely urbanized country of sixty million people is supposed to provide
homes for about the same number of rodent rats. You very rarely see any outside of
their favoured places, and they're very good at staying under cover and scurrying
from danger. Nevertheless, there's one heck of a lot of small vertebrates around
and among us and, when dead, none of them can scurry or flutter off anywhere.
When's the last time you saw a dead vertebrate? Apart from one of our Guinea girls
-they don't like being called 'pigs', and this one died of an unnatural cause known
as old age- I can't recall having seen such a thing since fishing a drowned mouse
from our rain barrel about a year ago. Every year, millions of squirrels, pigeons,
rats, rabbits, mice, sparrows and etc die, and rarely can any traces be noticed.
Where do all these corpses walk off to?
As it happens, I've got a translation of an old German article addressing that
question: Kosmos
presents What happens to dead animals?.
Virtually all small vertebrates are rapidly broken down and recycled but, somehow,
this didn't occur to our cast of characters from ancient Karoo.
Back to the grave
Gale, Owenetta, Milli and the skull remained entombed together in the Katberg
Formation several hundred kilometres south of Bloemfontein. They still remain together,
but have moved to the Rubridge Collection housed at Wellwood Farm. Various other
groups of corpses have been recovered over the years. However, they've generally
involved members of the same genus. There are several 'nests' of juvenile
dicynodonts named Lystrosaurus, and
these can contain bits of fifteen and more individuals. Rather than being literal
nests, these are more likely collections of drought victims; jumbles of remains
finally dumped together after the clouds burst too late to do those kids any good.
An entirely similar explanation wouldn't account for another dicynodont accumulation
from the Middle Triassic of China. The Nine Dragon Panel contains the appropriate
number of Parakannemeyeria, but these skeletons weren't swirled around by
rapid water. Their bones are still articulated.
Important announcement
I nipped out to the shop this afternoon, so the rest of these notes are being
written somewhat later. The significance of this excursion is partly contained in
the sighting of a dead mouse on the pavement. The chances of me mentioning a shortage
of dead mice and one turning up on the same day must be very low, and this leads me
to conclude that my above words likely contributed to the incident (see Sod's Law
for details). I can only offer my apologies and sincere regrets to any surviving
relatives of this unfortunate victim.
Gale & Co
This fossil commune was collected from a locality known as Fairydale Farm. At the
time, the farm comprised two adjoining properties: Fairydale 193 and Donald 207, and the
fossil-bearing outcrops actually occur on Don. That site produced bags of stuff
now spread around several South African collections, and much material is still
awaiting attention. Among the treasures is a skeleton of
Thrinaxodon, loads of Lystrosaurus
dicynodonts, lizardy-things such as Owenetta and
therocephalian therapsids. The precise
finding place of Gale and friends isn't recorded. Known is that this group potrait
was encased in red mudrock, and most of that material is found higher up than the
Lystrosaurus concentrations. That makes it probable that our friends
dropped dead somewhat later than those pests (p.508).
There's no indication of any weathering prior to burial. This suggests, when
entombed, these animals were either very recent departees from this earthly coil or
even still breathing. Gale and Owenetta possess their complete spines,
and their skulls are appropriately attached. Lots of ribs, the shoulders and hips
and partial limbs are also in place. The pair lie side by side, with the nearly
12cm Owenetta extending from level with Gale's pelvis to its breast region,
should the word be in any way appropriate. Lying on the former floor is part of a
skull from another, smaller Owenetta. It's body was found along with limb
parts a short distance from the two cosy sleepers, but no longer as part of the
tableau. Presumably, the rock was exposed and broke prior to collection.
Gale the cynodont
The uppermost five tail vertebrae are included
with the set, and the distance to the end of the snout is about 30cm. Its lower
jaw remains as do easily lost elements such as the quadrate, stapes and hyoid bones.
Also preserved and accounted for are a total of 26 spine bones, ribs, shoulder and
hip parts and partial limbs. Little has been displaced (p.510).
Who're you gonna call? Casebusters...
This orderly state of affairs indicates protection from interference such as kicking,
prodding, biting and other rude attentions, but also from floods, wind or getting
severely rained upon. In this instance, the team of paleosleuths coudn't take the
geological context of the surrounding sediments of the grave into account, seeing
as its original precise location is unknown.
The Casebusters were, however, able to clear Gale of any charges of assaulting
Owenetta. Gale's postcanines are small
teeth with strongly recurved main cusps. Uppers and lowers didn't occlude, and they
convinced the police that these slashers weren't capable of chewing food
properly prior to swallowing it, regardless of how much maternal nagging may
have occurred. Such recurved cusps are rare among recent cynodonts (meaning mammals),
although several seals have something of the kind. Recurved teeth can also be found
in the mouths of some snakes. In those cases, they have the function of barring the
front exit for small guests attempting to vacate the premises prior to encountering
the entertainments provided further inside their hungry host. On the balance of
probabilities, Gale was inclined to swallow animals with a single satisfying gulp.
Owenetta was too big and completely unsavaged.
What couldn't be discounted for Gale was a less than caring interest in the baby
Owenetta. In New
Zealand, late surviving sphenodont lizards and Bay City Rollers' fans can still be
found on some islands. The first mentioned, tuatara lizards, are known to shack up
with birds called fairy prions. They get along fine in their shared burrows, and
the tuataras show their gratitude by sometimes clearing up the eggs or babies.
Naturally enough, no such burrow-sharing behaviour has ever been observed for late
surviving Bay City Rollers' fans. The smell alone is far too offensive, let alone
the ghastly sounds produced by their record collections.
Hole sweet holes
Increasing numbers of therapsids are known to have been burrowers. Diictodon,
a dicynodont, Thrinaxodon and Trirarachodon
have all now been found dead in fossilized burrows. A number of collections of
cuddling juvenile tetrapods have been cited as probably being buried in cavities or
tunnels. Burrowing was a popular past-time. And, if different animals share their
homes today, then it was a likely possibility for the Permian and Triassic worlds
as well. New Zealand islands don't exactly evoke thoughts of semi-arid floodplains
such as Karoo. However, finding cooperative examples from areas with such conditions
poses no difficulty. Some reptiles are known to sleep with amphibians (hibernation
rather than copulation), kangaroo rats doss down with tortoises, and aardvarks shack
up with various critters. These are examples of peaceful communes. Some guests are
less well behaved. Gopher snakes reside in burrows of gophers, and attempt to
settle the rent questions by disposing of the host.
Traces of cohabitational behaviour can also be found in the more recent fossil
record. A beaver from the American Miocene, Palaeocastor, enjoyed building
oddly spiralled burrows. (Daimonelix is the exciting word used, should anybody like
annoying their opponents at Scrabble.) A long dead carnivore,
Zodiolestes, was found curled up in one.
The investigation concludes
The Casebusters weren't able to allay all suspicions in this instance, but the
Eastern Cape police found they had no chance of securing convictions for any of the
deaths, and the coroner recorded verdicts of death by misadventure for three out of
four of them. The explanation was plausible. A small group of animals were sharing
an abode- a cavity or perhaps a burrow- and something provoked a cave in. The
occupants were duly buried. Given the inadequacies of Lower Permian building
regulations, not even the architect got to face charges for negligence.
True, it's possible that Gale might have had some appetizing ideas concerning the
young Owenetta and presumably Milli. However, cynodonts beating up gecko-like
things and creepy crawlies happens to be a right enshrined in the South African
Constitution. At least, it ought to be.
Holotype corner
The type of Galesaurus planiceps, BMNH R36220, presently hangs out at the
Natural History Museum, London.
BP/1/ 478, of the Bernard Price Institute, Johannesburg, answers to the name of
Notictosaurus trigonocephalus.
Should you prefer conversing with Glochinodon dentidens, then send an e-mail
to TM 24 at the Transvaal Museum in Pretoria:
Glochinodon_dentidens@yahoo.com. Oh, as that address doesn't seem to work, you
could try asking TM 83 to have a word. That's the type of Gochinodontoides
gracilis.
Additional notes
Small specimens tended to be referred to
Galesaurus while larger individuals had a habit of becoming Glochinodontoides.
The distinctions had much to do with biological age.
Thanks
I'm again grateful to Palaeos for the nomenclatural collection. |
| Reference: | |
| Genus: Progalesaurus Sidor
CA & Smith RMH, 2004
'before Galesaurus'
Remarks: The generic name refers to the relatively basal nature
of the beast in comparison to Galesaurus, its closest
known relative. |
| Species: | Progalesaurus lootsbergenesis Sidor CA & Smith
RMH, 2004 |
| Place: | Lystrosaurus Assemblage Zone,
Karoo |
| Country: | South Africa |
| Age: | Lower Triassic |
| Remarks: | The following is based upon my reading of Sidor &
Smith, 2004.
Only a single specimen of Progalesaurus is presently known but it's a pretty good one;
a near complete skull and lower jaws. Most the body declined to display itself other than for
a bit of shoulder and vertebra (p.535). What little of the
skeleton there is resembles Thrinaxodon. These animals
were also of similar sizes. As the teeth suggest much the same tastes, there's a good
chance they selected its meals from the same menu. Both genera populated the
Lystrosaurus Assemblage Zone restaurant (the lower cafeteria in this case). That was a weird,
post-mass extinction world ridiculously dominated by one plant-eating, pig-sized
dicynodont. Progalesaurus looks the kind of
animal which would've made growing up for Lystrosaurus kids more interesting, more
exciting and somewhat less likely; meet, greet and eat. That's the career this predator
enjoyed. At least, I hope so.
The tradition of things
Karoo cynodonts of the Upper Permian and Lower Triassic Lystrosaurus Assemblage Zone
have traditionally been assigned to two families. The more primitive Procynosuchidae
consisted of Procynosuchus and the rest were herded into
Galesauridae. Many generic names have been coined for 'galesaurids' over the
years, but the ones which have remained valid are Bolotridon,
Cynosaurus, Galesaurus,
Platycraniellus and Thrinaxodon. In the scheme I'm presently following, the
latter pair are too derived for the family. Thrinax appears
more closely related with mammals than Galesaurus and
the same conclusion may be even more appropriate for Platy.
Dead in a ditch
The fossil remains were recovered from a drainage ditch in the vicinity of New Lootsberg
Pass (p.536). They were encased in a nugget of rock, and only reported their presence when
this was cracked open. It had come from a small outcrop of siltstone (p.538) which had been
deposited in the course of flooding on a generally semi-arid plain. Sandstone was laid down
in the former river channel itself, and the geological conditions indicate the speed of the
river was usually sedate.
Preservation
What's left is in pretty good condition, although some distortion and breakage has taken place.
Even that has its advantages. For example, the displacement of the lower jaws happens to have
exposed the front of the palate of the roof of the mouth. It's a lucky break in that regard.
A handsome head
This cynodont had a relatively short snout, and its eyes were set slightly in front of the
halfway line of the skull. They pointed roughly towards the front (a bit diagonally so),
which is a popular placement for forward looking carnivores. Many herbivores favour more
all-round views thanks to eyes being positioned further to the side. The length of the skull
is a touch over nine centimetres.
At this juncture I think we'll call on the resident site artist for one of his crude and
dodgy sketches. It's very loosely based on the illustration from page 539.
Progalesaurus.
Towards the front of the snout is a bone called the
septomaxilla, and this has a main body and a facial process. The latter portion is very
small in comparison with non-cynodont therapsids and early
cynodonts such as Procynosuchus (p.540). Most the side of the snout and front of the
rest of the head is supported by the maxilla, and this bone
is punctuated with a rich supply of small holes (foramina), particularly over the
canine. These were natural channels for cables such as nerves.
The maxilla curves inwards at the top to meet the nasal bone.
At their rear comes a jagged contact line with the lacrimal and jugal, with the latter being
met beneath the eye. Only part of the palatal process of the maxilla is visible, but the
position where it joins with the palatine is similar to that known for Galesaurus and
Cynosaurus.
The nasals are the roofing material of the snout, and they contribute little to the side
walls in this case. The roof was convex across its width but flattens to the rear. This
bone is also blessed with plenty of foramina, especially to the front. Part of the nasal
contacts with the lacrimal behind as in other basal cynodonts. The sutre between the nasal
and frontal bones is an upsidedown V-shape, and this is also typical for basal cynodonts.
A quick bit of cheek
The zygomatic arch is more familiarly known as the cheek
bone, although it's not actually built from a single element. The rear half for Progalesaurus
was provided by the squamosal (p.541) and, as with other relatively basal cynodonts (including
Thrinaxodon), this arch was robust and deepened along its
course towards the back.
Lower jaw
The lower jaws were found somewhat out of their natural position and disarticulated (p.545).
The mandible is much like that known from
Galesaurus, and it's more strongly constructed than in
basal relatives (and the more derived Thrinaxodon). In contrast to all extant mammals
(but not the earliest ones) the lower jaw was a multi-boned affair, but the
dentary dominated. The rear was composed of further elements.
A sprinkling of foramina pepper the outer face of the front of the dentary in no particular
pattern. A more substantial mental foramen is found on both sides about nine millimetres
behind the canine.
Teeth
This specimen provided the following numbers of teeth per side: (uppers): 4
incisors, 1 canine and ?7
postcanines; (lowers): 3, 1 and 9 respectively. (Dental
formulae were more variable among non-mammalian cynodonts than for mammals, and this had much
to do with serial replacement of teeth throughout a lifetime.)
Incisors
The upper front teeth were apparently long, thin and round in cross-section, although the
length might have been exaggerated as they're not now firmly affixed in their sockets. The
final pair are stronger than the first two. The lowers are fewsomer (a strange word I just
felt like inventing). Regardless of that linguistic indiscretion, they're also smaller than
their upper colleagues.
Canines
These teeth are oval in cross-section (p.546) and they display strirations (scratch marks).
Although the lower canine is a bit longer than the upper its partner has the thicker root.
Postcanines
Lower postcanines are both well preserved and exposed (p.547) whereas the uppers were granted
more obscurity. As with other galesaurids (and the
eucynodont Probelesodon aka Chiniquodon),
the lowers have 'strongly recurved' main cusps. That means the main cusp curves backwards,
perhaps so as to inform foodstuff of the recommended route, and the side profile reminds me of
a mitten containing 'clutching' fingers. Differences, however, concern accessory cusps.
These are well developed at the front of crowns for Progalesaurus, and that's unlike
the situation found in Cynosaurus and Galesaurus.
Upper postcanines
Remains can be seen of the right row and alveoli seem present
for postcanines one, two and four. The third position contains the ruins of a tooth. The
fifth is also poorly preserved but there was clearly no
buccal cingulum. Number six was probably larger. There's
a recurved main cusp with at least one accessory cusp behind. The seventh postcanine also
has a recurved accessory cusp in front of the main one. It's possible at least one more tooth
was present in life as an isolated crown was found in the matrix, and it must've come from
somewhere. It's presumed rather than known to be an upper postcanine.
Lower postcanines
Preservation is better for the lowers, and the best view is provided by the left jaw. The
postcanine series is complete. Its nine members become progressively both lower and larger
along the line from front to back. The teeth are positioned with a bit of a kink, so that the
rear of one is somewhat to the side of the front of its follower. The buccal sides are bereft
of cingula, which is similar to the situation known from Galesaurus. Number one is
hiding behind the canine, but the second gives a clear picture of the general scheme. There's
a strongly recurved main cusp and a number of well-developed accessory ones behind. By the
fourth in the series accessory cusps begin appearing to the front as well (p.548). The fifth
tooth is somewhat eccentric as it's actually smaller and has but one accessory cusp, but this
could be due to wear.
The body...
is largely absent. The nugget of rock contained the
scapula from a right shoulder and a bit of a vertebra.
These presumably belonged to the same owner, and are much like the equivalent bits of
Thrinaxodon.
Sorting your cynodonts
Sidor and Smith recognise the following South African genera as valid. The Upper Permian
Dicynodon Assemblage Zone has yielded Procynosuchus and Cynosaurus (p.549).
The Lower Triassic Lystrosaurus Assemblage Zone has contributed Progalesaurus,
Galesaurus, Thrinaxodon and Platycraniellus. A slight complication
arises as Cynosaurus remains have also been recovered from Lystrosaurus-yielding
strata, but the latter genus of dicynodont is now known to also occur in the final forty
metres of the Dicynodon AZ.
Affinities of Progalesaurus
The authors used 56 characters of the skull (32), mandible
(12) and teeth (12) from a dozen taxa for an analysis of phylogenetic relationships, and found
Progalesaurus to be most closely related within Galesaurus. Cynosaurus
occupies a more basal position with Galesauridae (as well as
being earlier). The position of Bolotriodon was less clear (p.550). It's relatively
sparsely represented but doesn't qualify for
Eucynodontia.
The world is dead. Long live the world
Progalesaurus was a galesaurid predator living in a very strange time. The wildlife
had been savagely denuded by extinctions late in the Permian. Only four terrestrial
vertebrate genera of Karoo clearly have fossil records from
both sides of the Permo-Triassic transition; Elonichthys, Lystrosaurus,
Tetracynodon and Owenetta (p.551). A more doubtful candidate is
Moschorhinus. For some reason the atmosphere appears to have become drastically
enriched with carbon dioxide and methane, and that had ruinous results. The great floodplain
of Karoo was no longer rich in undergrowth; bad news for small herbivores. Trees and shrubs
retreated from the landscape; bad news for larger herbivores. And, of course, that made bad
news for carnivores. This catastrophic serious of punches to the stomach of biodiversity
beat down within the time it took for about fifteen metres of sediment to build up. Estimates
suggest that was between 100,000 and half-a-million years.
Progalesaurus was found lurking about 35 metres above the P-T boundary. It was part
of the early cynodont recovery from oblivion, and that cynodont radiation was ultimately to
lead to some of the most successful and bizarre animals in global history. For example,
there's me. However, that doesn't mean galesaurids are direct ancestors of mine. Its
contemporary, Thrinaxodon, is more intimately linked with
we mammals, and the divergence of those two cynodont lines must've been back during the Upper
Permian.
Holotype
SAM-PK-K9954 is a resident of the South African Museum in Cape Town. The specific name refers
to the New Lootsberg Pass in Cape Province, which is where the sole specimen was found. |
| Reference: | Sidor & Smith (2004), A new galesaurid (Therapsida:
Cynodontia) from the Lower Triassic of South Africa, Palaeontology, 47(3), p.535-556.
|
| Links:
Dinosauricon features Brad McFeeters
http://dino.lm.com/images/display.php?id=2081
An illustration by Brad McFeeters. Looking at the teeth, Brad must have consulted the
paper carefully. The number of upper and lower incisors
conforms to galesaurid norms. I've not seen the description, but the postcanine teeth
as depicted are reminiscent of a sketch I have seen for Galesaurus. There's a
main cusp with an accessory one behind. The whiskers are based on well-founded,
circumstantial evidence and note also the lack of external ears and small amount of room
for the brain, when compared to mammals.
Sidor & Smith, 2004
http://www.washington.edu/burkemuseum/collections/paleontology/sidor/Sidor_Smith04.pdf
The paper is presently freely accessible on-line in pdf format.
"The discovery of Progalesaurus increases the number of valid Early Triassic
cynodonts to four and sheds light on the tempo of early cynodont diversification after the
end-Permian mass extinction." |
| Genus: Silphedocynodon
Abdala et al, 2006 (p.397) reveals this genus is based on a poorly preserved
juvenile cynodont of some affinities or other. It was referred to the
gomphodont family of Trirachodontidae but, as
far as can be told from the unclear remains of the teeth, it's more likely not a
gomphodont as the the postcanines are probably
sectorial. Preservation is too poor for certainty (or much usefulness). They
taunt this kid by terming it Cynodontia intecertae sedis. |
| Species: | Silphdocynodon gymnotemporalis |
| Place: | Cynognathus
Assemblage Zone, Karoo |
| Country: | South Africa |
| Age: | Lower - Middle Triassic |
| Remarks: | The genus isn't valid but I might as well
mention the type fossil. It's called BP/1/995 and may be sneered at in the
Bernard Price Institute for Palaeontological Research, Johannesburg. |
| Reference: | |
| Other reports
Xxxxxxxxx
Xxxxxxxxxx |
A. Permian cynodonts
B. Galesauridae
C. Thrinaxodontidae
| Taxon: Thrinaxodontidae
Assuming Nanocynodon isn't actually a member, this family presently contains a
single genus known from South Africa and Antarctica. As far as I'm aware, all fossils have
also been referred to the same species. Some Thrinaxodon-like teeth are reportedly
known from North America. As the source for that is the BBC Walking With Dinosaurs book,
it would be risky to assume they represent the family. Broadly Thrinaxodon-like
teeth are known from Morganucodon, the
basal mammal.
Genera: Ictidopsis (= Thrinaxodon), Micrictodon (= Thrinaxodon),
Notictosaurus (= Thrinaxodon), Nythosaurus (partly = Thrinaxodon),
Thrinaxodon, other reports
Time-Line:
Lower Triassic: Thrinaxodon |
| Genus: Thrinaxodon Seeley,
1894
'trident tooth'
Aka: Ictidopsis, Micrictodon, Notictosaurus, Nythosaurus
(partly).
Remarks: The following is informal even by my somewhat anarchic standards. As information has
mainly come from my own Mesozoic Eucynodonts - an internet directory,
I suppose I'm citing myself. Some general background has been provided by Benton, 1990,
Chapters 2 and 3 (especially pages 52-68).
Thrinaxodon, a fan's view
Thrinaxodon was a smallish, meateating cynodont
of the Lower Triassic. Large specimens could be termed
fox-sized, but only
when compared with the smaller end of the range. The length of head and body could
approach fifty centimetres.
Although not a mammal, (Mammalia hadn't been conceived 245
million years ago), 'trident tooth' was an active animal with a relatively high-octane
lifestyle. The anatomy isn't consistent with anything like a 'reptilian' mode of
existence. This creature was endothermic to some degree, ('warm blooded'), and probably
hairy. If one happened to trot by it would look very odd, but more like a mammal than
anything else. The skeleton does a fine impersonation of being an early attempt at
mammalness. Some significant differences will be mentioned below.
Apocalypse then
The world was in a very strange mood when Thrinaxodon was alive. Despite being
half-a-metre long or less, it was one of the largest land predators around. Most fossils
have come from the Karoo Basin of southern Africa, which was a vast flood plain for fast
flowing rivers. Somewhat earlier, during the Upper Permian, the river systems had flowed
more sedately and the place was rich in bio-variety. However, the Earth suffered a chronic
eco-crisis and something like 95% of all species disappeared. Our human rulers, in all
their wisdom, don't have enough nuclear weapons to achieve a similar level of destruction,
but let's try not to falsify my assertion by testing it. The Permian-Triassic transition
was marked by the most catastrophic mass extinction(s) in history.
Diet
'Trident tooth' had a relatively fuel hungry body, and couldn't have afforded to be all that
fussy about what it ate. However, a large proportion of its diet must have been provided by
a herbivorous dicynodont called Lystrosaurus.
This can be said with an unusually high level of confidence because there weren't all that
many alternatives on the menu. The rock strata concerned are concentrated into the
Lystrosaurus Assemblage Zone, and they represent much of the Lower Triassic. The
justification for naming the unit after that vertebrate
is strong to the point of absurdity. This single genus provides an incredible 90% of all
vertebrate remains. Even more ridiculously, the situation is similar in contemporary
faunas from Asia, Russia and Antarctica. Biodiversity was spectacularly dull.
An entirely non-technical look at the body
A Thrinaxodon neck was composed of seven bones. This is the same number as found in
myself, a blue whale and a shrew. Seven neck vertebrae is a feature of virtually every
mammal on the planet today. The only exceptions I've heard of are sloths and sea cows.
Even giraffes don't stick their necks out in this regard.
Take a deep breath
In contrast to most other land-living vertebrates then around, its upper body was clearly
differentiated into breast and lumbar regions. Generally, ribs continue all the way down
to the hips. However, if you'd like to take a quick peek at your chest, (or that of an
intimate acquaintance), you'll notice that in mammals the ribs stop at about two-thirds of
the way down the torso. This isn't exactly the situation with Thrinaxodon, but well
developed ribs aren't found on the lumbar vertebrae. (There were non-mammalian features
called costal plates, and these subsequently diminished over time.) The rib cage protects
organs such as heart and liver. But its absence lower down allows space for a membrane
called a diaphragm. This works in support of the lungs and enables a more efficient use of
oxygen. This is very useful to animals with high metabolic rates.
Open wide please
If Thrinaxodon would now open its mouth, (thanks and please don't snap it shut until
I say so)… The postcanine cheek teeth had three main cusps and thus the name. At the roof
of the mouth is a bony palate. This separates the food hole of the throat from the air
hole of the nose. Generally, no bony palate is present in reptiles, and that's why they
can't breathe and eat at the same time. Then again, as reptiles have got relatively low
metabolic rates, (compared to cynodonts such as myself), they don't have any reason to.
Thrinaxodon might have used this simultaneous intake of food and air as a party
trick, but it more plausibly reflects a need to process both fuels efficiently, which
points to a high metabolic rate. These features make sense in the context of endothermic
animals.
Putting it all together
Making sure to notice the nice, pointy cones on the postcanine teeth for reasonably
effective food chewing, we'll now allow Thrinaxodon to close its mouth.
Unfortunately, soft tissues don't generally fossilize. That means we've only got the hard
bones to go on. If you'd care to look at the tip of the snout, you should be able to make
out things called foramina. They're small pits and short channels. There are some on both
the upper jaw bone called the maxilla and the front of the nasals, which are the nose
bones. Quite what these were for is uncertain. However, such pits are known from dogs
and cats. They would've been of much use for supplying whiskers and a snuffling nose with
blood and nerves and, taken in combination with the space for the diaphragm, the bony
palate and the differentiated teeth, fur wouldn't be a surprising characteristic for an
endothermic critter, which is most likely what these animals were. Whiskers are
specialized hairs and hair is known to provide insulation.
So what?
I have personal reasons for my interest in this critter. It's more mammal-like than
anything known from earlier rocks. However, it's not quite near enough to qualify for
membership of a group called Eucynodontia; the 'true
dog teeth'. The oldest remains of eucynodonts presently come from the next level up in the
geological sandwich. In the Karoo Basin, that upper
level is termed the Cynognathus Assemblage Zone. I'm one of the more recent
eucynodont specimens.
| Reassigned species: T. brasiliensis Barberena, Bonaparte & Teixeira,
1987 = Prozostrodon brasiliensis | |
| Species: | Thrinaxodon liorhinus Seeley HG, 1894 |
| Aka: | Ictidopsis elegans Broom R, 1912; I. formosa von Hoepen
ECN, 1916; Micrictodon marionae Broom R, 1937; Notitctosaurus gracilis,
Notictosaurus luckhoffi Broom R, 1936; Nythosaurus larvatus,
Thrinaxodon putterilli Broom R, 1932 |
| Place: | Lystrosaurus Assemblage Zone,
Karoo & lower Fremouw
Formation |
| Country: | South Africa & Antarctica |
| Age: | Lower Triassic |
| Remarks: | The first couple of paragraphs are based upon my
reading of Kemp, 2005 (p.64).
A somewhat more intimate glance
Thrinaxodon is easily the most common and best known cynodont from its fauna.
Compared to its Permian relative, Procynosuchus, it's more
derived. The postcanines
are fewer in number, and the rear ones have sharp central cusps with accessory ones both
in front and behind. This tricusped arrangement accounts for the generic name, but it's
also a feature shared with basal mammals. These teeth aren't
as sophisticated as the later versions (eg.
Morganucodon), and there's no close alignment of uppers with lowers.
The dentary provides an increased share of the lower jaw,
and its coronoid process is more strongly developed. Further distinctions from the earlier
cynodont include an enlarged hole behind the orbit called
the temporal fenestra, and a more pronounced
zygomatic arch of the cheek. These features are connected with enhanced chewing
muscles and abilities.
What a body!
A somewhat puzzling characteristic of the spine are large
costal plates where the ribs meet the vertebrae. These
overlap with one another, and each has an impressive ridge for anchoring muscles. The
vertebrae also have extra articulations. Quite what the point of these features was isn't
clear. One suggestion concerns an increased lateral bending ability for the spine, while a
second opinion is the opposite; greater rigidity. Whatever the function, later cynodonts
either reduced or entirely dispensed with costal plates.
The legs were nearing the mammalian mode of being attached vertically beneath the body, but
they sprawled sideways to a moderate degree, especially the front ones. The tail is
relatively short, and this helps suggest that more muscle power was invested in proud
movement and momentum.
Walking With Dinosaurs - a guest appearance
Viewers of the BBC Walking With Dinosaurs series, (it was called Im Reich der Giganten in
Germany), may recall that the first episode featured a pair of cynodonts around 220
million years ago. Perhaps so as not to cause offence to prudes, they were a married
couple with babies living in a cosy hole. A gang of rude
dinosaurs found their happy home and acted in very annoying ways. What with all the
yelling and scratching, the cynodonts decided to move to pastures new. After taking good
care of the kids, (the parents ate them), the couple trotted off into obscurity for the
rest of the series.
Understandably, this all involved some artistic licence. They modelled the cynodonts on
Thrinaxodon, (p.25), which had been dead for over 20 million years and was utterly
incapable of further procreation. Still, there were
eucynodont carnivores of the right sort of size and larger, (eg.
Chiniquodon). Inconveniently, none are
available beyond 225 mya. A fair number of the non-dinosaurian cast happened to be
severely dead at the 'time' depicted. The producers could have avoided these continuity
problems by setting the scene earlier, but that would've meant a very limited number of
dinosaurs and no pterosaurs. A bit of creative
book-keeping provided a more scenic solution.
A subsequent publication suggests a further incorrectitude occurred. As far as is known,
adult Thrinaxodon lived...
Home alone
Damiani et al, 2003 is a description of an undoubtedly Thrinaxodon burrow, (p.1747).
This reasonably common fossil has frequently been found in a curled-up pose, and that was
thought to be indicative of death in burrows. As the former resident is entombed in its
home in this instance, there's no reason for doubt concerning the identity of the
architect. And, unromantically, there's no sign of a double bed.
This is none too surprising. Among living adult cynodonts, (ie.
mammals), coupling is a very popular activity. Actually
living in couples is an aberration most mammals leave to the birds.
Fossilized holes
Given that a burrow is a hollow space, the notion that some might fossilize can sound odd.
However, holes are potential moulds. If they happen to fill up with suitable material such
as mud, then a cast of the inside can form. The conditions of the Karoo floodplain have
provided quite a number. Should the mud have flowed in quickly enough, the fatal
consequences can provide an unequivocal identification of the builder. As well as
Thrinaxodon, an Upper Permian dicynodont,
Diictodon, and a Lower-Middle Triassic eucynodont,
Trirachodon, have also been caught in compromising positions. The killing
mechanism for these burrowers was probably flash flooding.
Age
The Thrinaxodon burrow cast was found in Free State Province along with three further,
unoccupied specimens. They came from mudrock deposits which include the Permian-Triassic
boundary. The authors cite the age as 'close to 251 Myr ago', (p.1748).
Architecture
Preserved is the animal's bedroom and part of the shaft leading to the front door. How long
that shaft was is unknown. Its floor is characteristic for non-mammalian cynodont paw-work,
in that it slopes to both sides from the middle; it has the profile of a gentle wedge.
(This is also the case for Trirachodon homes.) This is due to the way the animal
walked. Its posture was more upright than allowed by the leg joints of less derived
therapsids, (eg. dicynodonts), but less so than for mammals. The tunnel is also
proportionately narrower relative to bodysize than dicynodonts could manage, which certainly
saved digging and perhaps afforded some modest advantage against housebreakers. An animal
with forwards pointing knees requires less space than bandy-legged walkers.
The walls and lower parts of the ceiling contain areas with low, parallel ridges, and these
are presumably scratch marks left over from the construction work. As no such traces
remain on the floor, they were probably erased by subsequent comings and goings.
Thrinaxodon also provided a home for subtenants at some stage. Burrow casts left by
small invertebrates occur here and there, and these are commonly found in South African
mudrock of this age.
Setting
The burrow was probably dug in damp conditions next to a water course. Sooner or later,
the water became aggressive and swept lots of sand in, although this doesn't appear to have
been instantaneous as there's evidence of layering. Nevertheless, it was fatal. The
unfortunate victim was a large individual now lacking only the feet and tip of the tail.
The skeleton was beginning to fall to pieces. Some bones are disarticulated and most
teeth had time to fall from their sockets. Two canines and
four incisors are still in the jaws but fourteen assorted
incisors and postcanines are spread around the snout.
As most bones are still joined together, complete burial couldn't have taken all that much
time but it wasn't immediate.
Shelter from the storm
Thrinaxodon has no obvious adaptations for a fossorial (digging) way of life, but
you don't have to be that specialised to dig a burrow, (p.1750). Given the appalling
slaughter of species towards the end of the Permian, spending much time under ground was
very possibly an even better idea than usual. It would have provided some protection against
various potential causes of death. Circumstantial evidence suggests further Lower Triassic
therapsids may also have enjoyed digging; Lystrosarus (
Dicynodontia) and Bauria (Therocephalia).
As it's estimated that at least half of all living mammals are burrowers, the history of
synapsid tunnelling may have much historical depth.
News from Antarctica
Retallack et al, 2005 is a study concerning the P-T boundary in the deep south. As in
South Africa, the earliest Triassic fauna is dominated by dicynodonts. Most vertebrate
fossils from Victoria Land and the Transantarctic Mountains can't be identified with
certainty. However, there are exceptions; eg. Lystrosarus curvatus, L. murrayi,
L. mccaigi (only known from the Permian in South Africa) and Myosarus
gracilis.
T. liorhinus did its best to keep them fit, as the species is known from Graphite
Peak and Thrinaxodon Col; the only geogrphic location I know of named in honour of a
non-mammalian cynodont. At least one specimen, including a skull and
vertebrae, has since made its way to the South African
Museum. The paper is linked below.
Synonyms
The synonyms listed above mostly came from Colbert & Kitching, 1977 (p.3).
However, another was contained in Abdala, 2007 (p.614).
Holotype corner
The type fossil, BMNH R511, attempts to keep order in the collection of the Natural
History Museum, London. However, this task is made more difficult by the inane
babblings of R1715. That specimen roams the corridors claiming to be Nythosaurus
larvatus, the poor thing.
Meanwhile, in Johannesburg's Berdard Price Institute, BP/1/472 draws attention to
itself by insisting on being called Notictosaurus gracilis.
Confusion is spread at Wellwood. The Rubidge collection's haunted by the antics of
RC 107, an animal deluded enough to believe itself to be Notictosaurus
luckhoffi.
The Transvaal Museum of Cape Town's TM 1486 takes pleasure from being called
Micrictodon marionae.
Sadest of all may be NMQ R810 at the National Musum, Bloemfontein. It maintains
it could be the holotype of Thrinaxodon putterilli, but it isn't certain. |
| References: | Seeley (1894), Researches on the structure, organization and
classification of the fossil Reptilia. Part IX, section 1, On the Therosuchia, Philosophical
Transactions of the Royal Society, London, B, 185, p.987-1018. |
| Broom (1912), On some new fossil reptiles from the Permian and
Triassic beds of South Africa, Proceedings of the Zoological Society, London, p.859-876. |
| Hoepen (1916), Preliminary notice of new reptiles of the Karroo
Formation, Annals of the Transvaal Museum, 5(3), 2 pp. |
| Broom (1932), The mammal-like reptiles of South Africa and the origin
of mammals, London, H. F. and G. Witherby, 376 pp. |
| Broom (1936), On some new genera and species of Karroo fossil reptiles,
with notes on some others, Annals of the Transvaal Museum, 18, p.349-386. |
| Broom (1937), A further contribution to our knowledge of the fossil
reptiles of the Karroo, Proceedings of the Zoological Society, London, (B), 107,
p.299-318. |
| Links:
Digimorph - Thrinaxodon liorhinus
http://www.digimorph.org/specimens/Thrinaxodon_liorhinus/
A University of Texas scan of the skull.
Antarctic Science, Retallack et al, 2005
http://www.jhu.edu/~eps/faculty/jahren/RetallackJahren2005.pdf
Retallack GJ, Jahren AH, Sheldon ND, Chakrabarti R, Metzger CA & Smith RMH, The
Permian-Triassic boundary in Antarctica, Antarctic Science, 17 (2).
Fresh findings in the Earth's deep freezer. (The lack of page numbers in the citation
may indicate this is a pre-publication copy.)
Still Walking with Dinosaurs: Marxist Reflections on Evolution and Mass Extinctions by
José Villa
http://www.whatnextjournal.co.uk/Pages/Back/Wnext16/Dinosaur.html
A Marxist perspective on paleontology and related matters including Walking With Dinosaurs.
"There is no evidence whatsoever to suggest that the North American Coelophysis and
the South African Thrinaxodon Cynodonts inhabited the same place and even less that they
lived by stealing eggs from each other, or that the American Utah-raptor lived in
"Europe", or that the Anurognathus flying reptile found only in Germany lived on
the body of the giant North American Diplodocus as modern birds live around large African
mammals."
True, but the makers didn't claim otherwise. Thrinaxodon was already long dead.
However, smaller cynodonts and Coelophysus certainly lived at the same time. |
| Other reports
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| 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.
With thanks to all the featured sources.
Trevor Dykes, July 2005 Latest update: 14.7.2009
Ktdykes@arcor.de |
Bibliography:
Abdala F (2007), Redescription of Platycraniellus elegans (Therapsida,
Cynodonita) from the Lower Triassic of South Africa, and the cladistic relationships
of eutheriodonts, Palaeontology, 50(3), p.591-618.
Abdala F & Allinson M (2005), The taxonomic status of Parathrinaxodon
proops (Terapsida: Cynodontia), with comments on the morphology of the palate in
basal cynodonts, Palaeont. afr., 41, p.45.52.
Abdala F, Cisneros JC & Smith RMH (2006), Faunal aggregation in the Early
Triassic Karoo Basin: earliest evidence of shelter-sharing behaviour among
tetrapods?, Palaios, 21, p.507-512.
Abdala F & Giannini NP (2002), Chiniquodontid Cynodonts: Systematic and
Morphometric Considerations. Palaeontology, Vol. 45, Part 6, p.1151-1170.
Abdala F, Hancox PJ & Neveling J (2005), Cynodonts from the uppermost
Burgersdorp Formation, South Africa, and their bearing on the biostratigraphy and
correlation of the Triassic Cynognathus Assemblage Zone, Journal of Vertebrate
Paleontology, 25(1), p.192-199.
Abdala F, Neveling J & Welman J (2006), A new trirachodontid cynodont
from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort
Group, South Africa and the cladistic relationships of Gondwanan gomphodonts,
Zoological Journal of the Linnean Society, 147, p.383-413.
Battail B & Surkov MV (2000), Mammal-like reptiles from Russia, Chapter 6
in Benton MJ, Shishkin MA, Unwin AM & Kurochkin EN (Eds.), The age of
dinosaurs in Russian and Mongolia, Cambridge University Press.
Benton MJ (1990), The Reign of the Reptiles. Eagle Editions, (printed 1998), ISBN
1-902328-17-5.
Botha-Brink J & Abdala F (2008), A new cynodont record from the Tropidostoma
Assemblage Zone of the Beaufort Group: implications for the early evolution of cynodonts
in South Africa, Palaeont. af., 43, p.1-6.
Botha J, Abdala F & Smith R (2007), The oldest cynodont: new clues on the
origin and early diversification of the Cynodontia, Zoological Journal of the Linnean
Society, 149, p.477-492.
Colbert EH & Kitching JW (1977), Triassic cynodont reptiles from Antarctica,
American Museum Novitates, 2611, p.1-29.
Damiani R, Modesto S, Yates A & Neveling J (2003), Earliest evidence of cynodont
burrowing, Proceeding of the Royal Society of London B, 270, p.1747-1751.
Haines T (1999), Im Reich der Giganten, VGS, ISBN 3-8025-1401-7.
Kammerer CF & Abdala F (2009), Case 3431, Procynosuchus Broom, 1937
(Therapsida, Cynodontia): proposed precedence over Cyrbassiodon Broom, 1931 and
Parathrinaxodon Parrington, 1936, Bulletin of Zoological Nomenclature, 66(1),
p.64-69.
Kemp TS (2005), The Origin and Evolution of Mammals, Oxford University Press,
pp.331.
Modesto SP & Rybczynski N (2000), The amniote faunas of the Russian Permian:
implications for Late Permian terrestrial vertebrate biogeography, p17-34, Chapter
2 in Benton MJ, Shishkin MA, Unwin AM & Kurochkin EN (Eds.), The age of
dinosaurs in Russian and Mongolia, Cambridge University Press.
Ochev VG & Surkov MV (2000), The history of excavation of Permo-Triassic
vertebrates from eastern Europe, p1-16, Chapter 1 in Benton MJ, Shishkin MA,
Unwin AM & Kurochkin EN (Eds.), The age of dinosaurs in Russian and Mongolia,
Cambridge University Press.
Retallack GJ, Jahren AH, Sheldon ND, Chakrabarti R, Metzger CA & Smith RMH,
(2005), The Permian-Triassic boundary in Antarctica, Antarctic Science, 17 (2).
Sidor CA & Smith RMH (2004), A new galesaurid (Therapsida: Cynodontia) from the
Lower Triassic of South Africa, Palaeontology, 47(3), p.535-556.
Smith RMH & Ward PD (2001), Pattern of vertebrate extinctions across an event
bed at the Permian-Triassic boundary in the Karoo Basin of South Africa, Geology, 29(12),
p.1147-1150.
Tverdokhlebov VP, Tverdokhlebov GI, Minikh AV, Surkov MV & Benton MJ (2005),
Upper Permian vertebrates and their sedimentological context in the South Urals, Russia,
Earth-Science Reviews, 69, p.27-77. |
