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The latest issue of _Lethaia_ has a new ichthyosaur paper
that I haven't seen mentioned here (apologies if it has been..
the search engine at the archives isn't working right now).
Maisch, M. W. & Matzke, A. T. 2002. The skull of a large
Lower Triassic ichthyosaur from Spitsbergen and its
implications for the origin of Ichthyosauria. _Lethaia_ 35,
The specimen concerned is from the Sticky Keep Fm (??) -
this is Spathian in age - and represents the largest Triassic
ichthyosaur yet reported (the Sikanni giant from British
Columbia has certainly been 'reported' but not scientifically
described). The specimen is not new; it was discovered in
1969 and described (briefly) and figured by Mazin (1981,
What is most significant is that it preserves the caudoventral
part of the cheek, demonstrating that the animal was diapsid
in construction. Maisch and Matzke conclude that the
evidence now favours placement of ichthyosaurs within
Diapsida but they argue that the debate is still not over as
there are no known diapsids that appear to be suitable
ichthyosaur ancestors (they may or may not mention
hupehsuchians: I haven't yet read the whole paper). This is
significant because Maisch has previously argued strongly
against the idea that ichthyosaurs are diapsids, favouring for
them a basal reptile position instead. See in particular....
Maisch, M. W. 1998. The temporal region of the Middle
Jurassic ichthyosaur _Ophthalmosaurus_ ? further evidence
for the non-diapsid cranial architecture of the Ichthyosauria.
_Neues Jahrbuch fur Geologie und Palaontologie,
Monatshefte_ 1998, 401-414.
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