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Sauroniops, new thick-skulled carcharodontosaurid theropod from Upper Cretaceous of Morocco



From: Ben Creisler
bcreisler@gmail.com


A new online paper:


Andrea Cau, Fabio M. Dalla Vecchia & Matteo Fabbri
A thick-skulled theropod (Dinosauria, Saurischia) from the Upper
Cretaceous of Morocco with implications for carcharodontosaurid
cranial evolution.
Cretaceous Research (advance online publication)
http://dx.doi.org/10.1016/j.cretres.2012.09.002
http://www.sciencedirect.com/science/article/pii/S0195667112001395



In this study, we erect Sauroniops pachytholus gen. et sp. nov., a
large-bodied theropod dinosaur from the Cenomanian (Upper Cretaceous)
of Morocco, on the basis of an almost complete frontal showing a
unique combination of features including a naso–frontal suture
extended along 40% of the frontal length, a thick dome in the
anterolateral corner of the dorsal surface, a trapezoidal prefrontal
facet that is restricted to the anterodorsal margin of the lateral
surface of the frontal with no participation in the orbital roof and
separated from the lacrimal facet by a narrow vertical lamina, a
hypertrophied ‘D-shaped’ lacrimal facet that is four times the
anterior depth of the postorbital facet, and a raised posteromedial
margin of the dorsal surface describing a saddle with the
anterolateral dome and confluent with a series of anteromedial
rugosities. Phylogenetic analysis found robust support for placing
Sauroniops among the basal carcharodontosaurids and related to
Eocarcharia, showed that some of the unusual features of the new
theropod were convergently acquired by abelisaurids, and revealed a
mosaic pattern in the evolution of the carcharodontosaurid skull
table. The frontals of Sauroniops and Carcharodontosaurus, both from
the ‘Kem Kem compound assemblage’ of Morocco, show comparable size but
differ in the extent of the naso–frontal articulation, the shape and
disposition of the prefrontal and lacrimal articulations, the
development of dorsal ornamentation and the morphology of the
supratemporal fossa. Among carcharodontosaurids, the skull table
developed unique configurations among each lineage and appears
diagnostic at the species-level. The dome-like frontal in Sauroniops
may indicate head-butting behaviour in this taxon or evolved for
visual display.

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Highlights


► A new giant theropod dinosaur from the Cretaceous of Morocco is
erected. ► It is referred to Carcharodontosauridae based on skull roof
synapomorphies. ► This theropod shows a frontal dome and ornamentation
convergent with abelisaurids. ► Homoplasy and taxonomic values of
carcharodontosaurid skull tables are discussed.