Re: NEW RHYNCHOSAUR & TEMNOSPONDYLS

[christian farrell kammerer <cfkammer@midway.uchicago.edu>]

Well, Darren was complaining that no one was announcing new refs of the
fascinating work being done on non-dinosaurian Mesozoic tetrapods, so I'll
throw my hat in and help out. Forgive me if any of these have been
discussed previously--I don't seem to remember any of them coming up on
the list, though.

First, ichthyosaurs:
Sander, Martin P. 2000. Ichthyosauria: their diversity, distribution, and
phylogeny. Palaontogische Zeitschrift. 74(1/2): 1-35.

Sounds familiar? It should, because it addresses the same problem as
Motani, 1999--producing a phylogenetic analysis for the whole of the
Ichthyopterygia. Unlike Motani, however, it used only well-known taxa
(historically well-known, while excluding some rather complete but
recently-described genera like Caypullisaurus) and produced rather
different results (If any of you ichthyosaur buffs out there don't have a 
copy of Motani, 1999b, do yourself a favor and find it!). Some of these
differences include Sander finding a monophyletic traditional
Shastasauridae (that is, one that includes Cymbospondylus), recognition of
Phalarodon as a valid genus (for the moment at least), finding a
paraphyletic Temnodontosaurus (with T. burgundiae closer to "advanced"
ichthyosaurs than T. platyodon), and no support found for Motani's
Thunnosauria, Ophthalmosauria  and Eurhinosauria. Sander creates a new
taxon, Neoichthyosauria (not to be confused with Motani's Euichthyosauria)
for Temodontosaurus and "advanced" ichthyosaurs (e.g. Suevoleviathan,
Ichthyosaurus, Eurhinosaurus, Ophthalmosaurus, etc.) 

Then there's:
Arkhangelsky, M.S. 2000. On the ichthyosaur _Otschevia_ from the Volgian
Stage of the Volga Region. Paleontological Zhurnal. 34(5):pg. 549
The apparently diverse Russian ophthalmosaurs (Plutoniosaurus,
Paraophthalmosaurus, Otschevia) were unfortunately not used in Motani,
1999b because of their poorly-elucidated relationships, good comparisons
to other genera, and fragmentary nature (they were not dealt with in
Sander). This paper should help the situation somewhat, providing a
revised generic diagnosis for the title genus. The species Brachypterygius
zhuralevi is put in Otschevia, and new material (incomplete postcranium)
of the species is described. Continuing on the ichthyosaurs, there is:

Maisch, Michael W. 2000. Observations on Triassic Ichthyosaurs. Part VI. 
On the cranial osteology of Shastasaurus alexandrae Merrian, 1902 from
the Hosselkus Limestone (Carnian, Late Triassic) of Northern California
with a revision of the genus. N. Jb. Geol. Palaont. Abh. 217(1):1-25.
S. alexandrae is found to be the only good species in the genus based on
reexamination of the type skull. The type species, S. pacificus (which S.
alexandrae is often sunk into) may be nondiagnostic (or chimaeric--with
the vertebrae belonging to Californosaurus), but since it is lost this
cannot be decided. As such, it is retained as valid for now. All other
species are either found to be junior synonyms of S. alexandrae
(altispinus and osmonti), nomena dubia (careyi, merriami, carinthiacus,
nordensis, sieversi), or belonging in new genera (neubigi and
neoscapularis, the latter to be redescribed by Nicholls).
Relationship-wise, Shastasaurus is found to be closer to Mikadocephalus
than Cymbospondylus, and is considered more primitive than the former and
more derive than the latter (more support for Motani's placement of
Cymbospondylus a branch down from Mixosauria?)

Well, ichthyosaurs took longer than I expected so I'll send
non-dinosaurian archosaur and temnospondyl refs later.

-Christian Kammerer