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New Chaohusaurus (Ichthyosauria) species from Early Triassic of China.



From: Ben Creisler
bcreisler@gmail.com

A new paper (the pdf download does not appear to work for this link):


CHEN Xiaohong, P. Martin SANDER, CHENG Long and WANG Xiaofeng (2013)
A New Triassic Primitive Ichthyosaur from Yuanan, South China.
Acta Geologica Sinica (English Edition),87(3):672-677
http://www.geojournals.cn/dzxben/ch/reader/view_abstract.aspx?file_no=201303004&flag=1


Based on the systematic study of two fossil skeleton specimens
collected from the top of the third member of the marine Lower
Triassic Jialingjiang Formation of Yuanan, Hubei Province, South
China, a new Early Triassic primitive ichthyosaur Chaohusaurus
zhangjiawanensis sp. nov. is reported and described. The beds yielding
the type material are correlated with the Neospathodus homeri–N.
triangularis Conodont zone. The new taxon is most similar to
Chaohusaurus geishanensis Young and Dong, 1972 in the shape and
configuration of the scapula, forefin, pelvic girdle and hindfin,
presacral vertebral count and well-developed caudal peak, but
distinguished from the latter by its larger size, the position of the
pineal foramen in the centre of the parietal, the occurrence of a
larger calcaneum in hindfin and the first sacral rib with distal
expansion. The new species exhibits common features of primitive
ichthyosaurs such as: (1) the prefrontal has an antero-dorsal shelf
projecting towards the orbit; (2) the upper temporal fenestra is
small; (3) the postorbital and the squamosal meet laterally to the
upper temporal fenestra; and (4) cylindrical centra. However, more
derived ichthyosaur characters are seen with the frontal separated
from the orbital dorsal margin by the contact of the prefrontal and
postfrontal, which offer new clues to the early radiation of
ichthyosaurs.