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5 Acta Palaeontologica Polonica

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A new tritylodontid synapsid from Mongolia

100%

Watabe M. , Tsubamoto T. , Tsogtbaatar K.

2007

tom 52

nr 2

The Upper Jurassic Ulaan Malgait Beds in the Shar Teg locality of southwestern Mongolia have yielded remains of a new tritylodontid therapsid (Synapsida), Bienotheroides shartegensis sp. nov. The specimen consists of a fragmentary skull associated with lower jaws. It is assigned to Bienotheroides based on its short snout, a premaxilla−palatine contact, very reduced maxilla, relatively rounded corner of upper postcanine teeth (PC), and PC cusp formula of 2−3−3. It differs from the other species of Bienotheroides in having a much more reduced middle mesial cusp of PC. It further differs from B. zigongensis and B. ultimus in having shorter and wider PC, from B. ultimus in lacking a projection at the middle mesial margin of PC, and from B. wansienensis in lacking the vestigialmost mesiobuccal cusp of PC and in lacking a diastema between upper I1 and I2. This is the first discovery of the Tritylodontidae in Mongolia. This discovery extends the taxonomic (morphological) diversity and geographic range of Bienotheroides and underlies the success of the genus in the Middle to Late Jurassic biota of eastern Eurasia.

New features of the snout and orbit of a therocephalian therapsid from South Africa

100%

Sigurdsen T.

2006

tom 51

nr 1

I describe the anterior part of the externally poorly preserved skull of a therocephalian from the Karoo Basin in South Africa, using the method of serial grinding. The skull is incomplete, and its estimated length in life is 130 mm. The skull can be assigned to the Akidnognathidae with some confidence. The stratigraphic age of the specimen and its locality are not known, but the surrounding sediment suggests that it may be from the Upper Permian Dicynodon Assemblage Zone. It has five or six postcanine teeth, and a poorly developed crista choanalis. The sinuses and canals of the snout are recognized, and it is believed that the sinus positioned posteriorly in the snout (posterior maxillary sinus) is homologous with the maxillary sinus of anomodonts and cynodonts. It also shows similarities to the infraorbital canal of early mammals, such as Morganucodon. An anteriorly positioned sinus (anterior maxillary sinus), situated directly behind the canine root, is homologized with the maxillary sinus of gorgonopsians. In addition, I identify the previously undescribed canal (designated anterior maxillary canal), leading from the anterior maxillary sinus antero−dorsally. No evidence for maxilloturbinals was found in contrast to the condition known in the primitive therocephalian Glanosuchus

Bone histology of the graviportal dinocephalian therapsid Jonkeria from the middle Permian Tapinocephalus Assemblage Zone of the Karoo Basin of South Africa

80%

Bhat M. S. , Shelton C. D. , Chinsamy A.

tom 66

nr 4

Evolution and identity of synapsid carpal bones

80%

Kummel S. , Abdala F. , Sassoon J. , Abdala V.

nr 4

A new basal sphenacodontid synapsid from the Late Carboniferous of the Saar-Nahe Basin, Germany

80%

Frobisch J. , Schoch R. , Muller J. , Schindler T. , Schweiss D.

tom 56

nr 1

A new basal sphenacodontid synapsid, represented by an anterior portion of a mandible, demonstrates for the first time the presence of amniotes in the largest European Permo−Carboniferous basin, the Saar−Nahe Basin. The new taxon, Cryptovenator hirschbergeri gen. et sp. nov., is autapomorphic in the extreme shortness and robustness of the lower jaw, with moderate heterodonty, including the absence of a greatly reduced first tooth and only a slight caniniform development of the second and third teeth. Cryptovenatorshares with Dimetrodon, Sphenacodon, and Ctenospondylus, but notably not with Secodontosaurus, enlarged canines and a characteristic teardrop outline of the marginal teeth in lateral view, possession of a deep symphyseal region, and a strongly concave dorsal margin of the dentary. The new find shows that sphenacodontids were present in the Saar−Nahe Basin by the latest Carboniferous, predating the record of sphenacodontid tracks from slightly younger sediments in this region.