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Re: Eutretauranosuchus (Jurassic goniopholidid crocodylomorph) osteology



From: Ben Creisler
bcreisler@gmail.com

The paper is now available in open access on the AMNH site. The title
is corrected below--a chunk of embedded text ("no access") was
inadvertently copied from the website and included in the original
posting:

Adam C. Pritchard, Alan H. Turner, Eric R. Allen & Mark A. Norell (2013)
Osteology of a North American Goniopholidid (Eutretauranosuchus
delfsi) and Palate Evolution in Neosuchia.
American Museum Novitates Number 3783: 1-56
doi: http://dx.doi.org/10.1206/3783.2
http://digitallibrary.amnh.org/dspace/handle/2246/6449

On Thu, Oct 24, 2013 at 8:18 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> From: Ben Creisler
> bcreisler@gmail.com
>
> A new paper. Note that the open access version is not yet posted on
> the AMNH site.
>
>
> Adam C. Pritchard, Alan H. Turner, Eric R. Allen & Mark A. Norell (2013)
> Osteology of a North American Goniopholidid (Eutretauranosuchus
> delfsi) and Palate Evolution in Neosuchia no access.
> American Museum Novitates Number 3783: 1-56
> doi: http://dx.doi.org/10.1206/3783.2
> http://www.bioone.org/doi/abs/10.1206/3783.2
>
> [Not yet posted in open access:
> http://digitallibrary.amnh.org/dspace/handle/2246/9]
>
> The goniopholidid Eutretauranosuchus delfsi is currently known from
> two skulls from the Late Jurassic Morrison Formation of Colorado. Here
> we present a detailed osteology for a third Eutretauranosuchus delfsi
> specimen (AMNH FARB 570), consisting of a skull and fragmentary
> postcranium from Bone Cabin Quarry, Wyoming (Morrison Formation).
> Additional preparation, computed tomography (CT), and
> three-dimensional processing of CT images reveal matrix-covered
> structures on AMNH FARB 570, provide new information on goniopholidid
> cranial anatomy, and allow for the first description of an articulated
> North American goniopholidid braincase. These new data, along with
> restudy of the palatal anatomy in Eutretauranosuchus, provide valuable
> insight into the phylogenetic history of goniopholidid crocodyliforms.
> The skull of AMNH FARB 570 is extremely similar to other specimens of
> E. delfsi and Amphicotylus spp., especially in details of the
> architecture of the palate. In these Morrison Formation goniopholidids
> the secondary palate is incomplete such that the nasopharyngeal
> passage has no ventral floor. Additionally, there is a complex septum,
> constructed from the vomers and pterygoid, which extends ventrally
> near to the plane of the secondary palate. Characters diagnosing
> Eutretauranosuchus delfsi include: (1) an elongate, platyrostral
> skull; (2) a prominent depression on the posterolateral surface of the
> alveolar process of the maxilla; (3) minimal lateral undulation of the
> maxillary tooth row; (4) broad- ening of the nasals anterior to the
> prefrontals; (5) nasals that do not contact external nares; (6) a
> broad, flat interfenestral bar with raised rims along the
> supratemporal fenestrae; (7) a nasopharyngeal septum formed from
> diverging vomeral processes anteriorly and a midline pterygoid process
> posteriorly (also in Amphicotylus lucasii, AMNH FARB 5782); and (8) a
> vomeral septal complex that forms an X shape in cross section.
>
> Based on a revised phylogenetic analysis of 88 crocodylomorph taxa, a
> novel phylogenetic hypothesis is proposed in which a clade of
> Calsoyasuchus + Sunosuchus is sister to a clade of Goniopholis
> baryglyphaeus + (Goniopholis simus + (Amphicotylus lucasii +
> Eutretauranosuchus delfsi)). Examination of secondary palate
> characters in Goniopholididae suggests that this group “experimented”
> with changes to the bony secondary palate a number of times, resulting
> in morphologies not seen other mesoeucrocodylian clades.