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Aegisuchus, giant Late Cretaceous "shield crocodile" from Morocco in PLoS ONE



From: Ben Creisler
bcreisler@gmail.com


New in PLoS ONE:


Holliday, C.M. & Gardner, N.M. (2012)
A New Eusuchian Crocodyliform with Novel Cranial Integument and Its
Significance for the Origin and Evolution of Crocodylia.
PLoS ONE 7(1): e30471
doi:10.1371/journal.pone.0030471
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030471


Crocodyliforms were one of the most successful groups of Mesozoic
tetrapods, radiating into terrestrial, semiaquatic and marine
environments, while occupying numerous trophic niches, including
carnivorous, insectivorous, herbivorous, and piscivorous species.
Among these taxa were the enigmatic, poorly represented flat-headed
crocodyliforms from the late Cretaceous of northern Africa. Here we
report a new, giant crocodyliform from the early Late Cretaceous
(Cenomanian) Kem Kem Formation of Morocco. Represented by a partial
braincase, the taxon has an extremely long, flat skull with large jaw
and craniocervical muscles. The skull roof is ridged and ornamented
with a broad, rough boss surrounded by significant vascular
impressions, likely forming an integumentary structure unique among
crocodyliforms. Size estimates using endocranial volume indicate the
specimen was very large. The taxon possesses robust laterosphenoids
with laterally oriented capitate processes and isolated epipterygoids,
features allying it with derived eusuchians. Phylogenetic analysis
finds the taxon to be a derived eusuchian and sister taxon to
Aegyptosuchus, a poorly understood, early Late Cretaceous taxon from
the Bahariya formation. This clade forms the sister clade of
crown-group Crocodylia, making these taxa the earliest eusuchian
crocodyliforms known from Africa. These results shift phylogenetic and
biogeographical hypotheses on the origin of modern crocodylians
towards the circum-Tethyean region and provide important new data on
eusuchian morphology and evolution.


See news story with video:

http://www.physorg.com/news/2012-01-shieldcroc-species-ancient-crocodile.html