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Theropod material from Late Cretaceous of Morocco



From: Ben Creisler
bcreisler@gmail.com

A new online paper:

David C. Evans, Paul M. Barrett, Kirstin S. Brink & Matthew T. Carrano (2014)
Osteology and bone microstructure of new, small theropod dinosaur
material from the early Late Cretaceous of Morocco.
Gondwana Research (advance online publication)
http://dx.doi.org/10.1016/j.gr.2014.03.016
http://www.sciencedirect.com/science/article/pii/S1342937X14001075

The ‘Kem Kem beds’ of Morocco have yielded abundant material of
large-bodied theropod dinosaurs, but remains of small theropod taxa
are rare. Here, we describe two femora that provide additional
information on the diversity of small-bodied theropods in the
Gondwanan mid-Cretaceous. An almost complete femur (ROM 64666)
represents a noasaurid theropod based on the presence of the elongate
anteromedial flange that arises from the distal shaft and terminates
proximal to the distal end of the bone: osteohistological analysis
indicates that it was from a juvenile individual. It is possible that
this femur represents a juvenile Deltadromeus, which is recovered as a
putative noasaurid in some phylogenetic analyses. Nevertheless, as the
affinities of Deltadromeus are debated, this femur currently
represents the first definitive record of a noasaurid from northern
Africa and one of the few records of this clade from the early Late
Cretaceous. Moreover, if this specimen is not a juvenile Deltadromeus
then it probably represents a new addition to the Kem Kem theropod
assemblage. A second partial femur (ROM 65779) can be identified only
as an indeterminate averostran theropod. It is similar in size to ROM
64666, but the presence of an external fundamental system (EFS)
indicates that it pertained to a small-sized adult individual. These
observations indicate that the two femora described herein are from
different theropod taxa, thereby demonstrating that at least one
small-bodied theropod taxon was present in the Kem Kem fauna, adding
to the already high theropod species-richness of this unit.


Highlights
Morphology and bone histology of two theropod femora from the Kem Kem
beds of Morocco are described.
Growth marks indicating skeletal maturity in one femur provides
evidence of a small-bodied non-avian theropod in this assemblage.
A complete femur from a skeletally immature individual has diagnostic
features of Noasauridae.