[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Anthracosuchus, new dyrosaurid crocodylomorph from Paleocene of Colombia



From: Ben Creisler
bcreisler@gmail.com

A new non-dino, non-Mesozoic taxon that may be of interest:

Alexander K. Hasting, Jonathan I. Bloch & Carlos A. Jaramillo (2014)
A new blunt-snouted dyrosaurid, Anthracosuchus balrogus gen. et sp.
nov. (Crocodylomorpha, Mesoeucrocodylia), from the Palaeocene of
Colombia.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2014.918968
http://www.tandfonline.com/doi/full/10.1080/08912963.2014.918968#.U39hn_ldXTo

A new exceptionally brevirostrine dyrosaurid is described from the
middle Palaeocene (58–60 million years ago) Cerrejón Formation,
northeastern Colombia, based on four partial skulls and associated
postcrania. This taxon is unique among dyrosaurids not only in skull
shape, but also in having orbital tuberosities, and osteoderms that
are dorsoventrally thick and unpitted, a trait otherwise unknown in
Crocodylomorpha. Results from a cladistic analysis of Dyrosauridae
suggest that the new taxon, together with Cretaceous–Palaeocene
Chenanisuchus lateroculi from Africa and Cerrejonisuchus improcerus
also from the Cerrejón Formation, are the most basal members of the
family. Results from a biogeographic analysis indicate at least three
independent dispersals of dyrosaurids from Africa to the New World
occurred in the Late Cretaceous or early Palaeocene. Widely set orbits
in the new taxon indicate a deviation from surface-based predation,
characteristic of other dyrosaurids, to sub-surface predation, as in
modern Gavialis. Tooth impressions found on turtle shells recovered
from the same locality match well with teeth of the new taxon
indicating possible predation.