Triassic Cynodonts; Probainognathia, an internet directory

TRIASSIC CYNODONTS; Probainognathia, 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.

Probainognathia is a taxon of mainly meateating cynodonts first known from the Triassic. It's one of two main branches within Eucynodontia, which contains the most mammal-like of the 'mammal-like reptiles', (therapsids to their friends). The other branch is the mainly plant munching Cynognathia.
The earliest and most basal representative is the recently described Lumkuia from South Africa. Pending further discoveries, the fossilized action is then best known from South America. A major radiation not featured on this directory are the members of a superfamily called Chiniquodontoidea. Amongst their numbers are the yet more mammal-like tritheledontans; small non-mammalian cynodonts which survived into the Jurassic. A further taxon may be descended from that group, or something fairly similar within the ranks of the chiniquodontoids. These are interpreted by some to be the latest radiation of probainognathians and are known as mammals. I understand they're quite a successful taxon.
Or not...
(I should mention there's also support for mammalian origins lying within, or near to a family named Tritylodontidae. Until April 2005 I had that group down as cynognathians, but I presently treat them as probainognathian herbivores.)
Early days
The early fossil record of probainognathians isn't very extensive. As well as the aforementioned Lumkuia there's nothing much, and that seems to be an exaggeration. In the words of Rubige & Sidor, 2001, (p.469), all probainognathians share: "the lack of a pineal foramen and expanded ribs, as well as a posteriorly elongated secondary palate."
In creatures which have such a feature, (repetition for clarity, probainognathians don't), the pineal foramen is a hole in the head. It's an opening in the centre of the skull roof: "supposedly associated with a light-sensitive glandular structure, the pineal organ, which is a feature of many reptilian groups", (Benton 1990, p.55). This is also known as the 'third eye', and may have something to do with sensing the level of sunlight. It's located between two bones called parietals. I'm informed that it's probably not connected with the presence of a soft spot in the skull of small babies, because this is located where four bones meet, (the frontals and the parietals), rather than just the two. (With thanks to David Marjanovic for the discussion.)

Link:
T Mike Keesey, The Ages of the Mesozoic
http://www.dinosauricon.com/times/index.html
A moderner's map of the Mesozoic.

A. Lumkuia B. Probainognathidae C. Probainognathians

A. LUMKUIA

Genus: Lumkuia Hopson JA & Kitching JW, 2001

Species: Lumkuia fuzzi Hopson JA & Kitching JW, 2001

Place: Burgersdorp Formation, Karoo

Country: South Africa

Age: Lower Triassic

Remarks: This is presently the earliest known member of Probainognathia and it must be feeling rather lonely. Further traces of its relatives first appear in the fossil record of the Middle Triassic.
It's pictured on page 66 and briefly discussed on page 70 of Kemp, 2005. "It is modest sized..." is secure. Unfortunately, the skull length is given as 6cm in the text of the sektch, (p.65), but apparently doubles in size four pages later! Whichever is correct could be termed modest by some. There's no pineal foramen and the ribs are not encumbered by costal plates. The postcanines are fairly like those from the later chinquodontids. The crowns are high and narrow, and their tops are inwardly curving. These features make it derived in comparison with its contemporaries such as Cynognathus.
"However, it lacks the chiniquodontid features of a greatly elongated secondary palate, and the angulation of the ventral cranial margin", (p.70).
The sketch shows an impressive strong upper canine, and the neighbouring incisor has a similar shape, but it's smaller. Remains consist of the skull, the lower jaws and parts of the skeleton.
Holotype
The type fossil, BP/1/2669, stands sentry at the Bernard Price Institute, Johannesburg.

Reference: Hopson & Kitching (2001), A probainognathian cynodont from South Africa and the phylogeny of non-mammalian cynodonts. Bull. Mus. Comp. Zool., 156, p.5-35.

Seven Phases of Teeth (Postcanines)
I Carnivorous non-mammalian cynodonts
The following is derived from and inspired by my reading of Butler & Clements, 2001, (p.10).
The origins of mammalian postcanine teeth must have been in the mouths of their ancestors, and these seem to have been carnivorous, non-mammals. The most thoroughly studied representative in such respects is Thrinaxodon, which doesn't quite quality for Eucynodontia. Nevertheless, it's close. It lived a bit earlier than the first known eucynodonts such as Cynognathus. All its teeth were subject to replacement on a number of occasions, (not a mammalian trait), but they were differentiated into incisors, canines and postcanines.
There were six to eight upper and lower postcanines per side, but the uppers and lowers weren't in alignment with each other, (no occlusion). During a lifetime, the dentition shifted back towards the jaw joint. The front postcanines weren't always replaced by new ones at the same position. Vacated alveoli were plugged with bone, and teeth were added at the back of the line. The first tooth to erupt in any position usually had the more complex structure. As a consequence, the anterior postcanines tended to belong to older tooth generations, and the more complex ones were nearer the jaw joint. As the mouth operating muscles are also at the back, this is where the biting mechanism works most powerfully.
Go to Phase: I Carnivorous non-mammalian cynodonts, II Basal mammals, III Kuehneotheriids (basal Holotheria), IV Cladotheria, V Dryolestidae, VI Amphitheriida and Zatheria, VII Tribosphenic dentition.

A. Lumkuia B. Probainognathidae C. Probainognathians

B. PROBAINOGNATHIDAE

Taxon: Probainognathidae Romer AS, 1973
Reference: Romer (1973), The Chanares Formation (Argentina) Triassic reptile fauna XVIII, Probelesodon minor, a new species of carnivorous cynodont; family Probainognathidae nov. Brevoria, 401, p.1-4.

This taxon's apparently closely related to the Chiniquodontidae, and is sometimes assigned to it, (eg. Godefroit & Battail, 1997). However: "Advanced probainognathians can be divided into two subgroups, the chiniquodontids and a lineage including Probainognathus, tritheledontans, and mammals", (Rubidge & Sidor 2001, p.469). The chiniqs have a right-angled bend at the back of the upper jaw, and are more basal.

Genera: Lepagia, Probainognathus

Time-Line:
Upper Triassic: Lepagia
Middle Triassic: Probainognathus

Genus: Lepagia Hahn, Wild & Wouters, 1987
'for Lepage'
Remarks: The affinities of this genus are far from clear. It's based on a few isolated cynodont teeth from the microvertebrate sites of West Europe. They most closely resemble those of Probainognathus in form.
A few words on Lepage
The generic name honours Jean-Claude Lepage, a Belgian fossil hunter whose passionate searches uncovered cynodont remains in Luxembourg and France as well. As it happens, I've got a translation of an obituary here for Lepage and one of the authors of this genus, Georges Wouters. They frequently collaborated in their pursuits and, for unconnected reasons, both of these much respected amateurs happened to die within a couple of months of one another. Wouters had a car crash on 19.3.1992 and Lepage died from an illness on 17.5.1992. (The obituary, from a source unknown to me, happens to be in French. Helpfully, EF has supplied a translation as mon Francais c'est not terribly bon.)
Lepage was 45 when he stopped breathing, and most of his adult life had been spent in the army. He'd enlisted in 1968 and, after gaining experience with radios, became an air traffic controller at an airbase. 1990 saw him become a First Sergeant. He lived in the Gaume area (which includes the fossil locality of Habay-la-Vielle), and spent much effort looking for his ancient, distant relatives. Assuming haramiyidans are mammals, he spotted the oldest mammalian tooth from Belgium, now referred to Thomasia woutersi. That was the prelude for further eucynodonts from Habay-la-Vielle.

Species: Lepagia gaumensis Hahn, Wild & Wouters, 1987

Place: Habay-la-Vielle & Hallau & Saint-Nicolas-de-Point

Country: Belgium, Switzerland & France

Age: Norian (late) - Rhaetian (early), Upper Triassic

Remarks: The following is based upon my reading of Hahn et al, 1987 and thanks are due to the supplier.
In contrast to other ancient eucynodonts from this locality in Gaume, this genus didn't restrict its bequest to isolated tooth. It also supplied a tiny slither of lower jaw (p.4). Regardless of its size, hardly more than 1.5mm in length, it was most welcome and cooperatively informative. For one thing, it undoubtedly confirms which the lingual side is. Although much smaller than the standard model from South America, the authors found reason to refer the genus to Chiniquodontidae (p.5). Postcanines are long and narrow, and both sides run more or less in parallel with each other when viewed from the occlusal perspective. There's a main cusp and a somewhat variable number of accessories both before and behind; up to two. These cusps are arranged into an orderly row, and their slopes served as sharp blades. The enamel is flat and featureless, and the crown is bereft of any cingula. The length exceeds the width by around three times.
The root only just beats the crown in terms of height, looks pretty much rectangular in profile, and shows no enthusiasm for dividing. There is, however, a clear division between the root and crown.
The fragment of jaw preserves a relative wealth of information in comparison to its tiny size. It's nothing more than the bit required for housing the tooth. One side, certainly the lingual, has part of a sausage-like structure clamped onto it at about mid height. That's a bit of a splenial bone lodged in the Meckelian groove. The dentary's depth is twice that of the root of the tooth, which is naturally stored in the upper portion, and below that breakage enables a view of the alveolar canal.
The chiniq referral was using a relaxed approach to that family's extent. The most comparable critter then available with Probainognathus; not generally regarded as being a strict chiniq these days.
Postcanines
The type fossil has a pair of cusps to the front and rear. Together with the main cusp, they all contribute to straight line running along the length of the crown. The most externally situated are the smallest; from forward to rear: small, 'middling', large, 'middling', small. The main cusp is nearly symmetrical in profile, but the front slope is a touch more convex. Clear valleys separate each cusp from its neighbour(s). The pair at the front have worn tips whereas the rear duo are more like fully eradicated, their positions being indicated by wavy lines. These differences in wear is the strongest approach the postcanine takes to being asymmetrical when seen from the buccal perspective. That side of the main cusps bulges somewhat more than the lingual side (p.8).
Jaw
There's a very clear border between tooth and lower jaw on the buccal side, and the bone then bulges outwards below that. After that bulge, the wall of the dentary drops nearly vertically downwards, with just a small concavity intervening near the halfway mark. That sort of level is also shared by part of a foramin at the back. This side of the jaw, in the view of one acidic critic used to reviewing all action movies, is: "as dull as Love Story."
The level of thrills enacted by the lingual side is greater. The demarcation between the tooth and bone is less distinct, and the bone then descends straight down rather than bothering to first bulge. However, it makes up for that inactivity about halfway down; at the level of its Meckelian groove. That retains part of the sausage-like splenial, and the joint is visible to the fore so as to demonstrate this is certainly a distinct bone. Its identity is confirmed by comparison with the aforementioned Probainognathus. That better known South American has a similar arrangement of the vicinity below the postcanines. Apart from being a larger animal, Probainognathus is distinguished by carrying its Meckelian groove lower down nearer the base of the dentary, rather than around halfway.
Holotype
RM 28 is a tooth in the collection of the Institut royal des Sciences naturelles in Brussels. The specific name honours the area of Gaume. Several further teeth from Hallau, Switzerland were also referred to this species in the original description.
Additional notes
Godefroit & Battail 1997, (p.596), cite similarities and differences with and to both Chiniquodontidae and Dromatheriidae and leave the systematical placement open.

Reference: Hahn, Wild & Wouters (1987), Cynodontier-Zähne aus der Ober-Trias von Gaume (S-Belgien), Mèmoires pour servir à l'Explication des Carte Gèologiques et Minières de la Belgique, Mèmoire 24, p.1-33.

Genus: Probainognathus Romer AS, 1970
'advanced (in years) jaw' (With thanks to C.V. Vick)

Species: Probainognathus jenseni Romer AS, 1970

Place: Los Chanares Formation & Ischigualasto Formation

Country: Argentina

Age: Ladinian-Carnian, Middle-Upper Triassic

Remarks: Known from about three dozen specimens, the skull of this creature had a length of up to about 8.5cm, (Hurum 1998, p.84). Other specimens are apparently considerably smaller; down to lengths of a couple of cm.
A short nose
An unusual feature of this genus is the relative shortness of its muzzle. Abdala & Giannini, 2002 provide a comparison of the percentage of length of three regions of the skull in various non-mammalian cynodonts, (p.1159); the muzzle, the temporal and the orbital lengths. In P., the snout accounts for only 35% of the length. With the other nine featured taxa, the spread is between 40 - 54%. (Excluding probaino from the equation, the average figure is a bit less than 46,5%).
No mammalian jaw joint
Kemp, 2005 addresses the genus on page 70. The postcanines are reminiscent of both Thrinaxodon, (a non-eucynodont of the Lower Triassic), and the basal mammalian Morganucodon. They have a centrally placed line of three cusps running along the length of the crown. The central one is the most prominent. Further cusps can also be found.
The original description reported the presence of a small, mammalian jaw joint, but this was in error. The beginnings of a dentary-squamosal joint were said to be present, but the squamosal was actually being friendly with a different lower jaw bone, the surangular. This has been found in further eucynodonts. However, the dentary is closer to the squamosal than in any other non-mammalian taxa other than for tritheledontans. The relationship with mammals may not be as close as once thought, but it's nevertheless intimate.
One of the kids?
Adults are not generally enlarged versions of juniors. Their anatomy often differs in ways other than size. Baby mammals have relatively large heads (ask a new mother) and eyes. Growth in these features occurs relatively early. Such differences due to biological age have been enough for species and genera to be established. If only a few specimens are available, it can be far from obvious that an eleven centimetre skull with a relatively long snout is the juvenile stage for a 25cm skull with a shorter snout. (An example is presented by Chiniquodon, and it's by no means the only case.) Securely matching up parents and kids can be impossible.
Kemp, 2005 (p.78) reports on an earlier study of a juvenile probainognathian. This was the work of Bonaparte and Crompton in 1994. The individual is possibly Probainognathus. In some respects it appears more mammal-like than the adult form. "The prefrontal and postorbital bones are small and the frontal bone borders the orbit. The zygomatic arch is relatively more slender and the braincase relatiely larger. In the lower jaw, the dentary extends backwards very close indeed to the squamosal, and at the front end the symphasis is horizontal and unfused." To add to the fun, the postcanines are more similar to those of Morganucodon than adult Probainognathus.
Affinities
Romer originally assigned the fossil to the Chniquodontidae, but later established a separate family in 1973. It's sole chiniquodontid diagnostic feature: "is the elongated posterior extension of the palate", (Abdala & Giannini 2002, p.1157).
Stolen holotype
This fossil was either UPLR 16 or 17, both of which were stolen from the University of La Rioja, Argentina in 1994. (Abdala, 2007 pins it down to 17.) Other missing material includes the type fossils of Probelesodon lewisi and P. minor, (both since referred to the eucynodont genus of Chniquodon), and parts of a prosauropod called Riohasaurus incertus. Nothing had been recovered by 2000, (Chure D 2000, p.19).

Reference: Romer (1970), The Chanares (Argentina) Triassic reptile fauna. VI. A cynodont with an incipient squamosal-dentary articulation. Breviora 344, p.1-18.

Links:
DMG Projects, Probainognathus sp.
http://digimorph.org/specimens/Probainognathus_sp/
A report from the University of Texas on a juvenile skull. This includes a photo and QuickTime animations. This facility is producing some very interesting on-line material.

Larry Flank, Therapsid--Mammal Transitionary Series
http://www.geocities.com/CapeCanaveral/Hangar/2437/therapsd.htm
I like this essay a lot. Because of it, Larry Flank is partly responsible for setting off this catalogue of Mesozoic eucynodonts. Transitionary series is a well chosen term.

Mesozoic Eucynodonts in South America
For people who are unfamiliar with the word, (and don't worry, as this includes the vast majority), eucynodonts are mammals and their nearest non-mammalian relatives. The earliest members of the group are known from the Lower Triassic, (ca. 245 million years ago). Among the more recent representatives can be found myself. You're also a eucynodont, or a remarkably talented budgie. Making full use of the arbitrary powers available to any author, I'm now going to produce a school report on the eucynodont fossil record of South America.
Lower Triassic: a good effort but room for improvement.
Middle Triassic: excellent work. Keep it up!
Upper Triassic: world beating and making steady progress.
Entire Jurassic: a bit of jaw and a couple of footprints. I know another bit of jaw has been found, but it's pretty pathetic.
Most of the Cretaceous: Vincelestes is good but otherwise...
Uppermost Cretaceous: intriguing.
Lower Triassic
To be fair, the Permian-Triassic transition seems to have involved the most massive mass-extinction in the history of the planet. We're talking in terms of the disappearance of something like 75% of all tetrapod families. In such a context, any diversity at all is good going. South America can boast both meateating and predominantly plant-munching eucynodonts, and is only excelled in quality and quantity by South Africa. (It may be that the herbivores are lower Middle Triassic.)
Cynognathia: Cynognathus; Andescynodon; Rusconiodon; Pascualgnathus.
Middle Triassic
The south Brazilian state of Rio Grande do Sul contains an impressive variety of Triassic strata yielding terrestrial vertebrate remains. Eucynodonts are richly represented. The ages of the various formations have proven difficult to pin down. It appears that the Santa Maria Formation straddles the Middle-Upper Triassic border. Much is Ladinian and the upper reaches are Carnian. The latter stage is the opening episode of the Upper Triassic.
Brazil
The fauna is addressed at: Rio Grande do Sul, Triassic Vertebrates from Brazil
Argentina
The Los Chanares Formation seems to be about contemporaneous with the Ladinian of Rio Grande do Sul, (though opinions can vary).
Cynognathia: Massetognathus; Traversodon
Probainognathia: Candelariodon Chiniquodon; Probainognathus
Upper Triassic
South America is 'the' continent for Upper Triassic eucynodonts. It has riches beyond compare, and new forms are presently being described annually. Some of these are startlingly mammal-like. They're concentrated in various levels of the Carnian, although the following Norian stage may also be present. The uppermost Triassic (Rhaetian) is as yet unrepresented by eucynodonts. The aforementioned Rio Grande do Sul has claimed centre stage for new developments, but Argentina also has two formations of global significance, (Chanares and Ischigualasto).
Brazil
Go back to: Rio Grande do Sul, Triassic Vertebrates from Brazil, and have a look at the Santa Maria Formation (Carnian) and Caturrita Formation.
Argentina
Ischigualasto Formation
Cynognathia: Exaeretodon; Ischignathus
Probainognathia: Probainognathus; Chiniquodon; Ecteninion
Los Colorados Formation
Tritheledontans: Chaliminia
Jurassic
Unfortunately, the supply of eucynodonts then nosedives. There was no Jurassic record at all (aside from some footprints) until a couple of years ago. Patagonia has recently risen to the challenge, and provided a lower jaw from (Middle?) Jurassic Canodon Asfalto Formation. Though small, Asfaltomylos comes equipped with surprisingly derived molars. A second fossil is awaiting description.
Lower Cretaceous
Knowledge of South American mammaldom from this time span (45 million years or so) is restricted to just one genus, Vincelestes from La Amarga Formation of Patagonia. However, remains from a number of individuals have provided detailed information. Vincelestes is regarded as a zatherian, and anatomically fairly close to Boreosphenida. It seems to belong to a southern incursion of a then generally northern taxon.
Upper Cretaceous
The action remains centred in Patagonia, from whence a diverse array of derived dryolestoideans has been described. This group had its heyday in the Upper Jurassic and Lower Cretaceous of the north. These are largely mammals from the Campanian-Maastrichtian Los Alamitos Formation. It's not impossible that one genus could be a weird docodont, although this interpretation is disputed. The fauna also involves a gondwanatherian, (a group of unclear affinities), and some possible multituberculate remains.
These fossils are listed at: The Upper Cretaceous in Argentinian Patagonia.
Dryolestoidean material has also been reported from elsewhere in the continent, but not yet described. Based upon their diversity in the Paleocene, (immediately after the end of the Cretaceous), marsupials were also likely to have been resident at some time in the Upper Cretaceous, and a possible location is Laguna Umayo in Peru, (Peradectes austrinum).

Further Mesozoic site summaries can be found at Localities.

A. Lumkuia B. Probainognathidae C. Probainognathians

C. PROBAINOGNATHIANS

Taxon: None. This section contains probainognathians which are waiting to be pinned down more precisely.

Genera: Candelariodon, Ecteninion, "Hahnia", Trucidocynodon, other reports

Time-Line:
Upper Triassic: Ecteninion, "Hahnia", Trucidocynodon
Middle Triassic: Candelariodon

Genus: Candelariodon Oliveira TV de, Schultz CL, Soares MB & Rodrigues CN. 2011

Species: Candelariodon barberenai Oliveira et al, 2011

Place: Santa Maria Formation, Rio Grande do Sul

Country: Brazil

Age: Ladinian, Middle Triassic

Remarks: As yet, I've only seen the abstract. The genus is based on part of a lower jaw with some complete postcanine teeth. Mostly, these are slightly wider than might be expected, carry a main cusp that's tall and recurved, and it enjoys the company of one or two accessory cusps. However, one tooth towards the rear differs. That has two rows, each composed of four cusps, running along its length. A shallow basin runs between them.
The deviant postcanine is similar to the latter postcanines of Aleodon from Tanzania. The other teeth, however, are unlike their equivalents in that genus.
I've placed it in this section for want of having a better idea. The authors make no claim beyond it having been a carnivorous cynodont, and state further information is required in order to classify it more closely.

Reference: Oliveira et al (2011), A new carnivorous cynodont (Synapside, Therapsida) from the Brazilian Middle Triassic (Santa Maria Formation), Zootaxa 3027, p.19-28.

Genus: Ecteninion Martinez RN, May CL & Forster CA, 1996
'Stretched out back of head'
Remarks: According to an analysis by Abdala in 2007, this genus actually belongs within Cynoganthia rather than Probainognathia. However, until or unless that result receives support from elsewhere, I think it best to leave the entry here.
According to the first page of the description, which I just happened to find on line, the brain case is extremely elongated, thus the name.

Species: Ecteninion lunensis Martinez RN, May CL & Forster CA, 1996

Place: Ischigualasto Formation

Country: Argentina

Age: Carnian (middle), Upper Triassic

Remarks: Kemp, 2005 (p.65-66) includes a sketch, while page 70 provides some brief discussion. This seems to be a rather basal probainognathian, despite not being particularly early. For some reason, Kemp places it in "the Upper Triassic Chanares Formation". This can't be correct. It's not part of that fauna and the Formation happens to be Middle Triassic.
As with Lumkuia, this genus lacks specialisations of chiniquodonts. The secondary palate isn't greatly elongated, and it doesn't have the particular angulation of the ventral cranial margin.
Teeth
There are seven upper postcanines per side, the last trio of which are largest. Each is flattened across its width, and the shape causes an overlap with the subsequent tooth. There's a line of three sharp cusps, with the first being the largest and the third low. The four other postcanines are similar but they decrease in size progressively towards the canine. The lowers are unknown. Assuming they were none too different, they would probably be best employed on relatively soft parts of prey animals.
Flat head
Known from a nearly complete skull of about 11cm in length. It's been flattened at the back, almost as if it'd been violently stamped on. The holotype is in the collection of the Universidad Nacional de San Juan. For some reason, I have great difficulty spelling this name. Then again, there are times when I have problems with my own.
Holotype
PVSJ 422 presently resides at the Museo de Ciencias Naturales, Universidad de San Juan. The specific name is a reference to Valle de la Luna. That's where the skull was collected from by A. Arcucci.

Reference: Martinez et al (1996), A new carnivorous cynodont from the Ischigualasto formation (Late Triassic, Argentina), with comments on eucynodont phylogeny. Journal of Vertebrate Paleontology, 16(2), p.271-284.

Links:
The Journal of Vertebrate Paleontology 1996, 16(2), 271-284
http://www.vertpaleo.org/jvp/16-271-284.html
The abstract, "places Ecteninion in a trichotomy with Probainognathus and a monophyletic clade consisting of Tritylodontidae, Tritheledontidae and Morganucodon." This would be close to the roots of Mammaldom.

DMG Projects, Ecteninion lunensis
http://digimorph.org/specimens/Ecteninion_lunensis/
A further scanning project from the lads and lasses of the University of Texas lab.

Genus: "Hahnia" Godefroit P & Battail B, 1997
'for Hahn' (Prof Dr G Hahn)
Remarks: This generic name is preoccupied by a spider. The authors are aware of this, and will publish a replacement name in the future.

Species: "Hahnia" obliqua Godefroit P & Battail B, 1997

Place: Saint-Nicolas-de-Point

Country: France

Age: Norian late-Rhaetian early, Upper Triassic

Remarks: Apart from not yet having a proper name thanks to a spider, these teeth look rather boring. The crown slopes backwards and has three cusps, though that's more apparent when seen from above than it is from the side. The largest cusp, the middle one, has a "somewhat blunt" apex. Its two colleagues, which "are not very well separated from the main cusp", are "very blunt", (quotes from Godfroit & Battail 1997, p.588). "There is no constriction between the crown and the root."
Boring looking or not, these were nevertheless effective teeth for cutting up small portions of prey. The authors discuss similarities with teeth of galesaurids (something like forerunners of the eucynodonts), Cynognathus, chiniquodontids, tritheledontans, dromatheriids and various other small cynodonts of the European Upper Triassic; carnivores all, of one size or another. However, as there are also clear differences to the tiny teeth of "Hahnia", the authors plump for Cynodontia incertae sedis, (aka of some kind or other).

Reference: Godefroit P & Battail B (1997), Late Triassic cynodonts from Saint-Nicolas-de-Port (north-eastern France), Geodiversitas 19 (3), p.567-631.

Genus: Trucidocynodon Oliveira TV de, Soares MB & Schultz CL, 2010
Remarks: So far I've only seen the first page of this description.

Species: Trucidocynodon riograndensis Oliveira et al, 2010

Place: Santa Maria Formation

Country: Brazil

Age: Carnian (middle), Upper Triassic

Remarks: This taxon is based on a near complete skeleton showing much similarity with Ecteninion from Argentina. For example, both have elongated skulls, short secondary bony palates, impressively large canines and sectorial postcanines for making a mess of smaller animals. However, some skull details differ, Truci posseses pleasing srrated cutting edges on the upper incisors and, thankfully, has a generic name that's easier to spell. It's been nearly fifteen years since the description of Ecti..., Ecteninini... I've still got to look that damned name up!
Holotype
UFRGS PN-1051-T is a skeleton which, according to my notes, must be housed at the Universidade Federal do Rio Grande do Sul. At least, that's what I think the acronym stands for.

Reference: Oliveira et al (2010), Trucidocynodon riograndensis gen. et sp. nov. (Eucynodontia), a new cynodont from the Brazilian Upper Triassic (Santa Maria Formation), Zootaxa 2382, 71pp.

Other reports
Morondava Basin, Madagascar
Possible eucynodont remains were reported at the California Paleontological Conference in 1999, Upper Triassic or Lower Jurassic. These remains included the traversodontids, Dadadon and Menadon, described in 2000 and referred to the Middle Triassic. Further taxa have also been found but not as yet published.

Link:
Burmeister KC, Flynn JJ, Parrish JM & Wyss AR
http://www.geology.uiuc.edu/~burmeist/edu/CalPaleo.pdf
New Fossil Vertebtrates from the Northern Morondava Basin, Madagascar, and the Recovery of Micro Vertebrates from Coprolites. The Abstract. NB: Coprolites are fossilized dung.

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, October 2003 Latest update: 17.9.2011
Ktdykes@arcor.de

With further thanks due to:
Professor Pascal Godefroit, for kindly supplying the informative papers.

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 & Giannini NP AM (2002), Chiniquodontid Cynodonts: Systematic and Morphometric Considerations. Palaeontology, Vol. 45, Part 6, p.1151-1170.
Benton MJ (1990), The Reign of the Reptiles. Eagle Editions, (printed 1998), ISBN 1-902328-17-5.
Butler & Clemens (2001), Dental morphology of the Jurassic holotherian mammal Amphitherium, with a discussion of the evolution of mammalian post-canine dental formulae. Paleontology, 44 (1), p.1-20.
Chure D (2000), New threats to old bones, the theft of fossil vertebrates from museum collections, Cultural Resource Management, 23 (5), p.18-22.
Godefroit P & Battail B (1997), Late Triassic cynodonts from Saint-Nicolas-de- Port (north-eastern France). Geodiversitas, 19 (3), p.567-631.
Godefroit P (1999), New traversodontid (Therapsida: Cynodontia) teeth from the Upper Triassic of Habay-la-Vielle (southern Belgium). Paläontologische Zeitschrift 73 (3/4), 6 Abb. 1 Tab., p.385-394.
Hahn G, Wild R & Wouters G (1987), Cynodontier-Zähne aus der Ober-Trias von Gaume (S-Belgien), Mèmoires pour servir à l'Explication des Carte Gèologiques et Minières de la Belgique, Mèmoire 24, p.1-33.
Hurum JH (1998), The inner ear of two late Cretaceous Multituberculate mammals, and its implications for multituberculate hearing. Journal of Mammalian Evolution, 5 (1), p.65-93.
Kemp TS (2005), The Origin and Evolution of Mammals, Oxford University Press, pp.331.
Rubidge BS & Sidor CA (2001), Evolutionary patterns among Permo-Triassic therapsids. Annual Reviews of Ecology and Systematics 32, p.449-480.

Species:	*Lumkuia fuzzi* Hopson JA & Kitching JW, 2001
Place:	Burgersdorp Formation, Karoo
Country:	South Africa
Age:	Lower Triassic
Remarks:	This is presently the earliest known member of Probainognathia and it must be feeling rather lonely. Further traces of its relatives first appear in the fossil record of the Middle Triassic. It's pictured on page 66 and briefly discussed on page 70 of Kemp, 2005. "It is modest sized..." is secure. Unfortunately, the skull length is given as 6cm in the text of the sektch, (p.65), but apparently doubles in size four pages later! Whichever is correct could be termed modest by some. There's no pineal foramen and the ribs are not encumbered by costal plates. The postcanines are fairly like those from the later chinquodontids. The crowns are high and narrow, and their tops are inwardly curving. These features make it derived in comparison with its contemporaries such as Cynognathus. "However, it lacks the chiniquodontid features of a greatly elongated secondary palate, and the angulation of the ventral cranial margin", (p.70). The sketch shows an impressive strong upper canine, and the neighbouring incisor has a similar shape, but it's smaller. Remains consist of the skull, the lower jaws and parts of the skeleton. Holotype The type fossil, BP/1/2669, stands sentry at the Bernard Price Institute, Johannesburg.
Reference:	Hopson & Kitching (2001), A probainognathian cynodont from South Africa and the phylogeny of non-mammalian cynodonts. Bull. Mus. Comp. Zool., 156, p.5-35.

Species:	*Lepagia gaumensis* Hahn, Wild & Wouters, 1987
Place:	Habay-la-Vielle & Hallau & Saint-Nicolas-de-Point
Country:	Belgium, Switzerland & France
Age:	Norian (late) - Rhaetian (early), Upper Triassic
Remarks:	The following is based upon my reading of Hahn et al, 1987 and thanks are due to the supplier. In contrast to other ancient eucynodonts from this locality in Gaume, this genus didn't restrict its bequest to isolated tooth. It also supplied a tiny slither of lower jaw (p.4). Regardless of its size, hardly more than 1.5mm in length, it was most welcome and cooperatively informative. For one thing, it undoubtedly confirms which the lingual side is. Although much smaller than the standard model from South America, the authors found reason to refer the genus to Chiniquodontidae (p.5). Postcanines are long and narrow, and both sides run more or less in parallel with each other when viewed from the occlusal perspective. There's a main cusp and a somewhat variable number of accessories both before and behind; up to two. These cusps are arranged into an orderly row, and their slopes served as sharp blades. The enamel is flat and featureless, and the crown is bereft of any cingula. The length exceeds the width by around three times. The root only just beats the crown in terms of height, looks pretty much rectangular in profile, and shows no enthusiasm for dividing. There is, however, a clear division between the root and crown. The fragment of jaw preserves a relative wealth of information in comparison to its tiny size. It's nothing more than the bit required for housing the tooth. One side, certainly the lingual, has part of a sausage-like structure clamped onto it at about mid height. That's a bit of a splenial bone lodged in the Meckelian groove. The dentary's depth is twice that of the root of the tooth, which is naturally stored in the upper portion, and below that breakage enables a view of the alveolar canal. The chiniq referral was using a relaxed approach to that family's extent. The most comparable critter then available with Probainognathus; not generally regarded as being a strict chiniq these days. Postcanines The type fossil has a pair of cusps to the front and rear. Together with the main cusp, they all contribute to straight line running along the length of the crown. The most externally situated are the smallest; from forward to rear: small, 'middling', large, 'middling', small. The main cusp is nearly symmetrical in profile, but the front slope is a touch more convex. Clear valleys separate each cusp from its neighbour(s). The pair at the front have worn tips whereas the rear duo are more like fully eradicated, their positions being indicated by wavy lines. These differences in wear is the strongest approach the postcanine takes to being asymmetrical when seen from the buccal perspective. That side of the main cusps bulges somewhat more than the lingual side (p.8). Jaw There's a very clear border between tooth and lower jaw on the buccal side, and the bone then bulges outwards below that. After that bulge, the wall of the dentary drops nearly vertically downwards, with just a small concavity intervening near the halfway mark. That sort of level is also shared by part of a foramin at the back. This side of the jaw, in the view of one acidic critic used to reviewing all action movies, is: "as dull as Love Story." The level of thrills enacted by the lingual side is greater. The demarcation between the tooth and bone is less distinct, and the bone then descends straight down rather than bothering to first bulge. However, it makes up for that inactivity about halfway down; at the level of its Meckelian groove. That retains part of the sausage-like splenial, and the joint is visible to the fore so as to demonstrate this is certainly a distinct bone. Its identity is confirmed by comparison with the aforementioned Probainognathus. That better known South American has a similar arrangement of the vicinity below the postcanines. Apart from being a larger animal, Probainognathus is distinguished by carrying its Meckelian groove lower down nearer the base of the dentary, rather than around halfway. Holotype RM 28 is a tooth in the collection of the Institut royal des Sciences naturelles in Brussels. The specific name honours the area of Gaume. Several further teeth from Hallau, Switzerland were also referred to this species in the original description. Additional notes Godefroit & Battail 1997, (p.596), cite similarities and differences with and to both Chiniquodontidae and Dromatheriidae and leave the systematical placement open.
Reference:	Hahn, Wild & Wouters (1987), Cynodontier-Zähne aus der Ober-Trias von Gaume (S-Belgien), Mèmoires pour servir à l'Explication des Carte Gèologiques et Minières de la Belgique, Mèmoire 24, p.1-33.

Species:	*Probainognathus jenseni* Romer AS, 1970
Place:	Los Chanares Formation & Ischigualasto Formation
Country:	Argentina
Age:	Ladinian-Carnian, Middle-Upper Triassic
Remarks:	Known from about three dozen specimens, the skull of this creature had a length of up to about 8.5cm, (Hurum 1998, p.84). Other specimens are apparently considerably smaller; down to lengths of a couple of cm. A short nose An unusual feature of this genus is the relative shortness of its muzzle. Abdala & Giannini, 2002 provide a comparison of the percentage of length of three regions of the skull in various non-mammalian cynodonts, (p.1159); the muzzle, the temporal and the orbital lengths. In P., the snout accounts for only 35% of the length. With the other nine featured taxa, the spread is between 40 - 54%. (Excluding probaino from the equation, the average figure is a bit less than 46,5%). No mammalian jaw joint Kemp, 2005 addresses the genus on page 70. The postcanines are reminiscent of both Thrinaxodon, (a non-eucynodont of the Lower Triassic), and the basal mammalian Morganucodon. They have a centrally placed line of three cusps running along the length of the crown. The central one is the most prominent. Further cusps can also be found. The original description reported the presence of a small, mammalian jaw joint, but this was in error. The beginnings of a dentary-squamosal joint were said to be present, but the squamosal was actually being friendly with a different lower jaw bone, the surangular. This has been found in further eucynodonts. However, the dentary is closer to the squamosal than in any other non-mammalian taxa other than for tritheledontans. The relationship with mammals may not be as close as once thought, but it's nevertheless intimate. One of the kids? Adults are not generally enlarged versions of juniors. Their anatomy often differs in ways other than size. Baby mammals have relatively large heads (ask a new mother) and eyes. Growth in these features occurs relatively early. Such differences due to biological age have been enough for species and genera to be established. If only a few specimens are available, it can be far from obvious that an eleven centimetre skull with a relatively long snout is the juvenile stage for a 25cm skull with a shorter snout. (An example is presented by Chiniquodon, and it's by no means the only case.) Securely matching up parents and kids can be impossible. Kemp, 2005 (p.78) reports on an earlier study of a juvenile probainognathian. This was the work of Bonaparte and Crompton in 1994. The individual is possibly Probainognathus. In some respects it appears more mammal-like than the adult form. "The prefrontal and postorbital bones are small and the frontal bone borders the orbit. The zygomatic arch is relatively more slender and the braincase relatiely larger. In the lower jaw, the dentary extends backwards very close indeed to the squamosal, and at the front end the symphasis is horizontal and unfused." To add to the fun, the postcanines are more similar to those of Morganucodon than adult Probainognathus. Affinities Romer originally assigned the fossil to the Chniquodontidae, but later established a separate family in 1973. It's sole chiniquodontid diagnostic feature: "is the elongated posterior extension of the palate", (Abdala & Giannini 2002, p.1157). Stolen holotype This fossil was either UPLR 16 or 17, both of which were stolen from the University of La Rioja, Argentina in 1994. (Abdala, 2007 pins it down to 17.) Other missing material includes the type fossils of Probelesodon lewisi and P. minor, (both since referred to the eucynodont genus of Chniquodon), and parts of a prosauropod called Riohasaurus incertus. Nothing had been recovered by 2000, (Chure D 2000, p.19).
Reference:	Romer (1970), The Chanares (Argentina) Triassic reptile fauna. VI. A cynodont with an incipient squamosal-dentary articulation. Breviora 344, p.1-18.

Species:	*Candelariodon barberenai* Oliveira et al, 2011
Place:	Santa Maria Formation, Rio Grande do Sul
Country:	Brazil
Age:	Ladinian, Middle Triassic
Remarks:	As yet, I've only seen the abstract. The genus is based on part of a lower jaw with some complete postcanine teeth. Mostly, these are slightly wider than might be expected, carry a main cusp that's tall and recurved, and it enjoys the company of one or two accessory cusps. However, one tooth towards the rear differs. That has two rows, each composed of four cusps, running along its length. A shallow basin runs between them. The deviant postcanine is similar to the latter postcanines of Aleodon from Tanzania. The other teeth, however, are unlike their equivalents in that genus. I've placed it in this section for want of having a better idea. The authors make no claim beyond it having been a carnivorous cynodont, and state further information is required in order to classify it more closely.
Reference:	Oliveira et al (2011), A new carnivorous cynodont (Synapside, Therapsida) from the Brazilian Middle Triassic (Santa Maria Formation), Zootaxa 3027, p.19-28.

Species:	*Ecteninion lunensis* Martinez RN, May CL & Forster CA, 1996
Place:	Ischigualasto Formation
Country:	Argentina
Age:	Carnian (middle), Upper Triassic
Remarks:	Kemp, 2005 (p.65-66) includes a sketch, while page 70 provides some brief discussion. This seems to be a rather basal probainognathian, despite not being particularly early. For some reason, Kemp places it in "the Upper Triassic Chanares Formation". This can't be correct. It's not part of that fauna and the Formation happens to be Middle Triassic. As with Lumkuia, this genus lacks specialisations of chiniquodonts. The secondary palate isn't greatly elongated, and it doesn't have the particular angulation of the ventral cranial margin. Teeth There are seven upper postcanines per side, the last trio of which are largest. Each is flattened across its width, and the shape causes an overlap with the subsequent tooth. There's a line of three sharp cusps, with the first being the largest and the third low. The four other postcanines are similar but they decrease in size progressively towards the canine. The lowers are unknown. Assuming they were none too different, they would probably be best employed on relatively soft parts of prey animals. Flat head Known from a nearly complete skull of about 11cm in length. It's been flattened at the back, almost as if it'd been violently stamped on. The holotype is in the collection of the Universidad Nacional de San Juan. For some reason, I have great difficulty spelling this name. Then again, there are times when I have problems with my own. Holotype PVSJ 422 presently resides at the Museo de Ciencias Naturales, Universidad de San Juan. The specific name is a reference to Valle de la Luna. That's where the skull was collected from by A. Arcucci.
Reference:	Martinez et al (1996), A new carnivorous cynodont from the Ischigualasto formation (Late Triassic, Argentina), with comments on eucynodont phylogeny. Journal of Vertebrate Paleontology, 16(2), p.271-284.

Species:	*"Hahnia" obliqua* Godefroit P & Battail B, 1997
Place:	Saint-Nicolas-de-Point
Country:	France
Age:	Norian late-Rhaetian early, Upper Triassic
Remarks:	Apart from not yet having a proper name thanks to a spider, these teeth look rather boring. The crown slopes backwards and has three cusps, though that's more apparent when seen from above than it is from the side. The largest cusp, the middle one, has a "somewhat blunt" apex. Its two colleagues, which "are not very well separated from the main cusp", are "very blunt", (quotes from Godfroit & Battail 1997, p.588). "There is no constriction between the crown and the root." Boring looking or not, these were nevertheless effective teeth for cutting up small portions of prey. The authors discuss similarities with teeth of galesaurids (something like forerunners of the eucynodonts), Cynognathus, chiniquodontids, tritheledontans, dromatheriids and various other small cynodonts of the European Upper Triassic; carnivores all, of one size or another. However, as there are also clear differences to the tiny teeth of "Hahnia", the authors plump for Cynodontia incertae sedis, (aka of some kind or other).
Reference:	Godefroit P & Battail B (1997), Late Triassic cynodonts from Saint-Nicolas-de-Port (north-eastern France), Geodiversitas 19 (3), p.567-631.

Species:	*Trucidocynodon riograndensis* Oliveira et al, 2010
Place:	Santa Maria Formation
Country:	Brazil
Age:	Carnian (middle), Upper Triassic
Remarks:	This taxon is based on a near complete skeleton showing much similarity with Ecteninion from Argentina. For example, both have elongated skulls, short secondary bony palates, impressively large canines and sectorial postcanines for making a mess of smaller animals. However, some skull details differ, Truci posseses pleasing srrated cutting edges on the upper incisors and, thankfully, has a generic name that's easier to spell. It's been nearly fifteen years since the description of Ecti..., Ecteninini... I've still got to look that damned name up! Holotype UFRGS PN-1051-T is a skeleton which, according to my notes, must be housed at the Universidade Federal do Rio Grande do Sul. At least, that's what I think the acronym stands for.
Reference:	Oliveira et al (2010), Trucidocynodon riograndensis gen. et sp. nov. (Eucynodontia), a new cynodont from the Brazilian Upper Triassic (Santa Maria Formation), Zootaxa 2382, 71pp.