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Giant "shield croc" from Cretaceous of Morocco



From: Ben Creisler
bh480@scn.org

Another critter from the SVP meeting in the news:

Giant 'Shieldcroc' Once Stalked Moroccan Rivers

http://www.livescience.com/16896-giant-shield-croc-crocodile-fossils.html


SVP Abstracts 2011

HOLLIDAY, Casey, University of Missouri, Columbia, MO, USA; GARDNER,
Nicholas, Marshall University, Huntington, WV, USA.

A NEW EUSUCHIAN CROCODYLIFORM WITH NOVEL CRANIAL INTEGUMENT AND THE ORIGIN
OF CROCODYLIA. 

We describe a new, giant crocodilian discovered in the coastal deposits of
the early Late Cretaceous (Cenomanian) Kem Kem Beds of Morocco, a region
rich with crocodyliforms and dinosaurs. The taxon, represented by cranial
remains, has an extremely long, fat skull and a novel integumentary display
structure previously unknown for crocodyliforms, though similar to that
described for specimens discovered in the Cenomanian Bahariya Formation.
The frontals are ornamented by a series of thick obliquely-oriented
parallel ridges which expand caudally to form a broad, circular, rough bony
integumentary boss on the parietal. The boss is surrounded by a broad,
smooth, shallow fossa that communicates with deep vascular grooves which
emerge from small, constricted, vertical-walled, dorsotemporal fossae. With
the midline boss, this vasculature likely contributed to forming a
keratinous integumentary display structure previously undocumented for
crocodyliforms which also may have served a thermoregulatory function. The
skull bears a massive, rostrally-situated adductor tubercle, large,
sub-horizontally oriented fossae for jaw closing muscles and immense
post-occipital protuberances indicating the animal had a very fat profle.
The laterosphenoid bodies have small teardrop-shaped, isolated, vestigial
epipterygoids allying the taxon with derived neo-suchians. Applying
previous regression analyses from Alligator skull table width and
crocodyliform brain size suggest that the skull was well over 2 meters
long. Separate phylogenetic analyses using crocodyliform and crocodylian
matrices found the taxon to be a derived eusuchian and the sister taxon of
crown-clade Crocodylia making this group the earliest eusuchian
crocodyliforms known from Africa suggesting modern crocodylians may have
circum-Tethyan rather than North American origins.


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