New Mesozoic marine reptile stuff

[bh480@scn.org]

New Mesozoic marine reptile stuff

From: Ben Creisler
bh480@scn.org

The latest issue of Science magazine (Science 330: 1164-
1165(Nov. 26, 2010)) has a short article about new finds 
of Early Triassic marine reptile fossils from Chaohu 
region of China. 


Tamaki Sato, Yen-Nien Cheng, Xiao-Chun Wu and Chun Li 
(2010)
Osteology of Yunguisaurus (Reptilia; Sauropterygia), a 
Triassic Pistosauroid from China 
Paleontological Research 14(3):179-195. (2010) 
doi: 10.2517/1342-8144-14.3.179

 Triassic pistosauroids are closely related to the 
Plesiosauria which flourished later in the Mesozoic, but 
their fossil record has been poor due to the fragmentary 
nature of the known specimens. Yunguisaurus liae Cheng et 
al. (2006) (Reptilia, Sauropterygia) from China was the 
first Triassic pistosauroid represented by an almost 
complete skeleton, and we provide a full description of 
the holotype specimen based on the result of complete 
preparation of the skull and postcranium. A revised 
diagnosis characterizes Y. liae by a mixture of primitive 
and derived features for sauropterygians, such as the 
high number of cervical vertebrae (similar to the 
Plesiosauria) with large zygapophyses (shared with basal 
sauropterygians). The holotype skeleton likely represents 
a juvenile individual. In a revised phylogeny, 
relationships among the Triassic pistosauroids are fully 
resolved but weakly supported; the revised phylogeny 
differs from the existing hypothesis on a sauropterygian 
relationship, likely due to the previous reliance on 
fragmentary taxa. The long neck and hyperphalangy give an 
impression that Yunguisaurus is very ?plesiosaurian,? but 
detailed comparison revealed morphological differences in 
various parts of the postcranial. These differences, in 
combination with the revised phylogenetic hypothesis, 
suggest that Yunguisaurus was not necessarily comparable 
to the Plesiosauria in terms of body plan and mode of 
swimming.

http://www.bioone.org/doi/abs/10.2517/1342-8144-14.3.179


V. Fischer, A. Clément, M. Guiomar and P. Godefroit (2010)
The first definite record of a Valanginian ichthyosaur 
and its implications on the evolution of post-Liassic 
Ichthyosauria.
doi:10.1016/j.cretres.2010.11.005
Cretaceous Research (advance publication) 

A complete ichthyosaur rostrum, with 124 associated 
teeth, was recently discovered in Laux-Montaux locality, 
department of Drôme, southeastern France. The associated 
belemnites and ammonites indicate a late Valanginian age 
(Neocomites peregrinus Zone, Olcostephanus nicklesi 
Subzone) for this fossil, which consequently represents 
the first diagnostic ichthyosaur ever reported from 
Valanginian strata. This specimen also represents the 
first occurrence of Aegirosaurus outside the Tithonian 
(Upper Jurassic) lithographic limestones of Bavaria 
(southern Germany). Tooth morphology and wear pattern 
suggest that Aegirosaurus belonged to the ?Pierce II/ 
Generalist? feeding guild, which was hitherto not 
represented in post-Liassic ichthyosaurs. Most Late 
Jurassic ichthyosaurs actually crossed the Jurassic-
Cretaceous boundary.


Sharp-tooth ichthyosaur episode of  Naked Science on 
National Geographic Channel
The National Geographic Channel recently aired an episode 
of Naked Science about a  giant "sharp-tooth ichthyosaur" 
from the Triassic. discovered in Nevada in 2008. The 
critter has not been officially named or described yet 
but is quite interesting--it was probably the biggest 
predator of its day. Photos, art, short video, and info 
at:
http://channel.nationalgeographic.com/series/naked-
science/5125/Photos/4562e6f0d313c210VgnVCM1000000100007fRC
RD#tab-Overview

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