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Fwd: Mosasaurus conodon osteology and taxonomy



Apparently this posting to the DML did not show up. I will try again...

---------- Forwarded message ----------
From: Ben Creisler <bcreisler@gmail.com>
Date: Wed, Oct 29, 2014 at 8:57 AM
Subject: Mosasaurus conodon osteology and taxonomy
To: dinosaur@usc.edu


Ben Creisler
bcreisler@gmail.com

A new online paper:

T. Ikejiria and S.G. Lucas (2014)
Osteology and taxonomy of Mosasaurus conodon Cope 1881 from the Late
Cretaceous of North America.
Netherlands Journal of Geosciences (advance online publication)
DOI: http://dx.doi.org/10.1017/njg.2014.28
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9394587&fulltextType=RA&fileId=S0016774614000286


Two well-preserved skeletons of Mosasaurus conodon Cope 1881
(Squamata, Mosasaurinae) from the Pierre Shale (late Campanian) of
Colorado and the Bearpaw Shale (Late Campanian to Early Maastrichtian)
of Montana are described. The two specimens are important because they
provide new osteological information, especially on the skull
(including jaws with teeth) and forelimbs, whereas those elements are
largely missing in the holotype (AMNH 1380) of M. conodon.
Morphological comparisons of the holotype with the two new specimens
allow us to emend the diagnosis of the species in the genus
Mosasaurus, primarily using tooth and forelimb morphologies. Teeth of
M. conodon are unique in their combination of having a slender, gently
recurved overall shape (similar to Clidastes) with no serration on the
developed carinae (less developed in Clidastes). The tooth count of M.
conodon tends to be low (14–15 in the maxilla, 16 in the dentary and
eight in the pterygoid, respectively) when compared to other species,
such as Mosasaurus lemonnieri, Mosasaurus missouriensis and Mosasaurus
hoffmanni–Mosasaurus maximus. The forelimb is short in the species,
characterised by a much lower number of the manual digital formula,
4(+1?)–4(+2?)–4(+1?)–4(+1)–2 than other species of Mosasaurus. The
forelimb bones are generally robust, especially the box-shaped humerus
(width-to-length ratio 3/2). A variety of new morphological data
support the conclusions that (1) M. conodon is a nominal species, (2)
the European species M. lemonnieri is not a junior synonym and (3) one
of the most complete skeletons of Mosasaurus from South Dakota (SDSM
452) is not assigned to M. conodon (but is likely to be Mosasaurus
sp.). To date, M. conodon occurs only in North America during the late
Campanian to early Maastrichtian.