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Placodonts had European origin



From: Ben Creisler
bcreisler@gmail.com

A new paper:

James M. Neenan, Nicole Klein  & Torsten M. Scheyer (2013)
European origin of placodont marine reptiles and the evolution of
crushing dentition in Placodontia.
Nature Communications 4: 1621
doi:10.1038/ncomms2633
http://www.nature.com/ncomms/journal/v4/n3/full/ncomms2633.html

Sauropterygia was the most successful marine reptile radiation in
history, spanning almost the entire Mesozoic and exploiting a wide
range of habitats and ecological niches. Here we report a new,
exceptionally preserved skull of a juvenile stem placodont from the
early Middle Triassic of the Netherlands, thus indicating a western
Tethyan (European) origin for Placodontia, the most basal group of
sauropterygians. A single row of teeth on an enlarged palatine
supports this close relationship, although these are small and pointed
instead of broad and flat, as is the case in placodonts, which
demonstrate the strongest adaptation to a durophagous diet known in
any reptile. Peg-like, slightly procumbent premaxillary teeth and an
‘L-shaped’ jugal also confirm a close relationship to basal
placodonts. The new taxon provides insight into the evolution of
placodont dentition, representing a transitional morphology between
the plesiomorphic diapsid condition of palatal denticles and the
specialized crushing teeth of placodonts.


News release:

http://www.mediadesk.uzh.ch/articles/2013/der-pflasterzahnsaurier-ist-ein-europaeer_en.html