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Majiashanosaurus, new eosauropterygian from Early Triassic of China



Ben Creisler
bcreisler@gmail.com

In the new JVP:

Da-Yong Jiang, Ryosuke Motani, Andrea Tintori, Olivier Rieppel,
Guan-Bao Chen, Jian-Dong Huang, Rong Zhang, Zuo-Yu Sun & Cheng Ji
(2014)
The Early Triassic eosauropterygian Majiashanosaurus discocoracoidis,
gen. et sp. nov. (Reptilia, Sauropterygia), from Chaohu, Anhui
Province, People’s Republic of China.
Journal of Vertebrate Paleontology 34(5):  1044-1052
DOI:10.1080/02724634.2014.846264
http://www.tandfonline.com/doi/full/10.1080/02724634.2014.846264#.VA8KYPldXTo

Records of Early Triassic marine reptiles, when they first emerged
after the end Permian mass extinction, are rare. During an excavation
at Majiashan, Chaohu, Anhui Province, a new sauropterygian specimen
was found co-occurring with the ichthyopterygian Chaohusaurus from the
Upper Member of the Nanlinghu Formation, of Olenekian (Spathian, Early
Triassic) age, for which a new taxon, Majiashanosaurus
discocoracoidis, gen. et sp. nov., is erected. This skeleton is
exposed in ventral view, with the last three cervical vertebrae
together with 19 dorsal, three sacral, and more than 18 caudal
vertebrae preserved. The cervical centra are keeled ventrally, and
cervical ribs are double-headed, carrying a free anterior process. The
transverse processes of the dorsal vertebrae are not distinctively
elongated. The dorsal ribs are single-headed, and the clavicles
articulate on the anteromedial aspect of the scapula. The humerus is
curved. These features allow assignment to a new sauropterygian taxon.
The interclavicle has no posterior process, and the scapula is of
typical eosauropterygian shape, with a broad and ventrally expanded
glenoidal portion that is separated from a narrow posterodorsal blade
by a distinct constriction. The coracoid is round and plate-like
without a waist. This feature is different from that of all other
known eosauropterygians, but resembles that of placodonts.