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Cricosaurus (Thalattosuchia) from Jurassic of Mexico



From: Ben Creisler
bcreisler@gmail.com

A recent paper not yet mentioned on the DML:




Marie-Céline Buchy, Mark T. Young & Marco B. de Andrade (2013)
A new specimen of Cricosaurus saltillensis (Crocodylomorpha:
Metriorhynchidae) from the Upper Jurassic of Mexico: evidence for
craniofacial convergence within Metriorhynchidae.
Oryctos 10: 9-21.
http://www.dinosauria.org/oryctos-article.php?article=111

Here we describe a new specimen of the metriorhynchid crocodylomorph
Cricosaurus saltillensis. Furthermore, we amend the specific epithet
to use the masculine suffix rather than the neuter suffix (i.e.,
change saltillense to saltillensis). The new specimen, like the
holotype, is from the Tithonian (Upper Jurassic) La Caja Formation of
Gomez Farías, Mexico. Based on this new specimen, C. saltillensis had
proportionally the shortest snout and the shortest maxillary and
dentary tooth rows of any member of the subfamily Metriorhynchinae.
Furthermore, while the teeth are poorly preserved, carinae are visible
(a rare morphology within Cricosaurus). The enlarged intratemporal
flanges (anteromedial corners of the supratemporal fossae) demonstrate
that the fibre length of the supratemporal adductor muscles were
increased in C. saltillensis, this would have increased the medial
component of the force vectors thereby stabilising the skull against
torque. The reduced tooth count and carinated teeth, and a skull
adapted to better resist torque suggest C. saltillensis was better
suited to feeding on largebodied prey than other members of the genus
Cricosaurus.