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Theropod diversity in mid-Cretaceous of Tunisia, northern Africa



From: Ben Creisler
bcreisler@gmail.com

A new online paper:


Federico Fanti, Andrea Cau, Agnese Martinelli & Michela Contessi (2014)
Integrating palaeoecology and morphology in theropod diversity
estimation: a case from the Aptian-Albian of Tunisia.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
doi: http://dx.doi.org/10.1016/j.palaeo.2014.05.033
http://www.sciencedirect.com/science/article/pii/S0031018214002892


Current knowledge of theropod dinosaurs of northern Africa and their
diversity during the Early Cretaceous is deceptively fragmentary and
commonly associated with inadequate stratigraphic and palaeoecological
data. Thereby, confused taxonomic affinities of theropod remains,
represented primarily by isolated teeth and fragmentary skeletal
remains, resulted in speculations on the number of genera and their
stratigraphic, geographic and ecological distribution. In this study,
we introduce a discussion on the theropod diversity in the
Aptian–Albian of southern Tunisia based on a multidisciplinary
approach that combines detailed sedimentological analyses with
canonical morphological and phylogenetic analyses. This study
indicates the presence of three theropod clades, Spinosauridae,
Abelisauroidea, and Carcharodontosauridae. Relevant for the
identification of isolated specimens from the Saharan regions,
carcharodontosaurids are not represented in the Aptian-Albian teeth
record and thus relatively less abundant than spinosaurids and
abelisauroids. Five ziphodont tooth morphotypes are referred to
ontogenetic and/or positional differences among a single abelisauroid
taxon. The other three teeth morphotypes most likely represent two
distinct spinosaurid taxa. Finally, the calibrated stratigraphic
distribution of discussed elements indicates a clear ecological
partition between theropod taxa. In particular, abelisauroids and
carcharodontosaurids are commonly found in inland, fluvial deposits
together with titanosauriform and rebbachisaurid sauropods, and rare
crocodilians. Conversely, spinosaurids are limited to estuarine to
coastal deposits dominated by a rich and diverse crocodilian fauna
along with actinopterygians and sarcopterygians, including large-sized
coelacanthiforms.


Highlights
Theropod diversity in the mid-Cretaceous of northern Africa is discussed.
Detailed morphological, phylogenetic, and stratigraphic data are combined.
Saharan theropod include Spinosauridae, Abelisauroidea, and
Carcharodontosauridae.
Environment-related partitioning of specific group of taxa are discussed.