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Sungeodon, new dicyondont from Early Triassic of China



From: Ben Creisler
bcreisler@gmail.com

A new paper:


Michael W. Maisch & Andreas T.Matzke (2014)
Sungeodon kimkraemerae n. gen. n. sp., the oldest kannemeyeriiform
(Therapsida, Dicynodontia) and its implications for the early
diversification of large herbivores after the P/T boundary.
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 272(1): 1-12
DOI: http://dx.doi.org/10.1127/0077-7749/2014/0394
http://www.ingentaconnect.com/content/schweiz/njbgeol/2014/00000272/00000001/art00001

The dicynodont Sungeodon kimkraemerae n. gen. n. sp. is described on
the basis of a skull from the Lower Triassic Jiucaiyuan Formation of
Dalongkou (Junggar Basin, Xinjiang Uygur Autonomous Region, People's
Republic of China). It is the first representative of
Kannemeyeriiformes from the earliest Triassic. Kannemeyeriiforms were
the predominant clade of Triassic dicynodonts, which constituted a
major component of terrestrial Triassic ecosystems. The new taxon
helps closing one of the most significant gaps in the fossil record of
dicynodonts, since stem-kannemeyeriiforms are known from the Late
Permian, whereas the first true kannemeyeriiforms previously known are
late Early Triassic in age. After a phylogenetic analysis Sungeodon
belongs to the family Stahleckeriidae. Therefore, the Stahleckeriidae
may not have had its origin in Africa as previously assumed, but in
Central Asia. More importantly, Sungeodon also suggests that the major
radiation of kannemeyeriiform dicynodonts, including the emergence of
all relevant subgroups of this clade, occurred not later than in the
Early Triassic, soon after the end-Permian extinction. To date, only
few dicynodont taxa are known from the earliest Triassic, none of
which are kannemeyeriiforms. The addition of Sungeodon confirms
previous predictions that our knowledge of Early Triassic dicynodont
diversity and evolution is far from being complete, and that new
discoveries from historically low-sampled geographic regions may fill
this gap. A rapid post-extinction diversification of kannemeyeriiforms
also fits with the emerging picture from other clades, such as
archosaurs, of a rapid recovery from the end-Permian event in the
terrestrial realm.