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Psephoderma alpinum (Sauropterygia, Placodontia) from Late Triassic of Switzerland

Ben Creisler

A new online paper:

James M. Neenan & Torsten M. Scheyer (2014)
New specimen of Psephoderma alpinum (Sauropterygia, Placodontia) from
the Late Triassic of Schesaplana Mountain, Graubünden, Switzerland.
Swiss Journal of Geosciences (advance online publication)
DOI: 10.1007/s00015-014-0173-9

Psephoderma alpinum is an armoured, durophagous placodont known from
the alpine Late Triassic. Here we present a new, well-preserved
isolated skull discovered in the Alplihorn Member (Late Norian–Early
Rhaetian) of the Kössen Formation, Schesaplana Mountain, which
straddles the Swiss/Austrian border. Micro-computed tomographic (µCT)
scanning was used to create an accurate osteological reconstruction of
the specimen, the first time this has been conducted for Psephoderma.
We thus clarify disputed anatomical features from previous
descriptions, such as a lack of a lacrimal and a pineal foramen that
is enclosed by the parietal. We also present the first description
based on µCT data of the lateral braincase wall, sphenoid region and
some cranial nerve canals for Psephoderma, with the location of the
hypophyseal seat, cerebral carotid foramina, dorsum sellae, prootic
foramen, lacrimal foramen, as well as all dental foramina being
described. This specimen represents the first skull of Psephoderma
recovered in Switzerland, and features such as poorly-sutured
braincase elements and its relatively small size compared to other
known specimens may indicate that it was a sub-adult.