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SVP 2K review, part I
like to add to the chorus that this was one of the best meetings I've ever been
to! Met a few list members who I hadn't before, had a good time, got the
traditional post-SVP cold/sinus infection (and I'm not the only
wasn't a talk with any real outstanding new specimens presented (at least none I
saw), but that doesn't mean that there were lots of extremely interesting talks
bits and pieces from the technical sessions:
Missing Data Symposium was great for the methodologically oriented. Lots
of potentially useful approaches discussed. Very few bones,
see the Great Biotic Interchange talks, as I had planned. Bummer.
Good reviews in the Paleo of Lower Vertebrates symposium.
Plenary Session, Sumida et al. detailed the upland German Early Permian
fauna (that contains _Eudibamus_, actually). An extremely interesting bit
for those interested in predator/prey ratios: _Dimetrodon_ (the only sizable
predator known there) is extremely rare, while the main large herbivores
(_Diadectes_ and another, as-yet-unnamed diadectomorph) make up something like
95% of the fauna. Kind of challenges the idea of a high pred/prey ratio
for the Early Permian, at least for this assemblage...
et al. described how many features of the plates of _Stegosaurus_ are
constructional artifacts (i.e., are the natural consequence of the method of
growth), and suggested that display would have been the primary function.
Thermoregulation, if used, would have been a secondary
talk: lots of cladograms. New news (somewhat rushed through): support for
Tyrannosauridae + Ornithomimosauria is greatly reduced, and I suspect the next
iteration will find Tyrannosauridae outside Maniraptoriformes; Troodontidae
winds up in two equally most parsimonious positions: as the sister taxon to
Dromaeosauridae OR as the sister taxon to Alvarezsauridae (!), together the
sister group to _Archaeopteryx_ plus later birds.
Alroy's simulation of the extinction patterns of Pleistocene mammals was
interesting: he showed that using realistic parameters for human hunting ability
and growth rates, you can wipe out the North American megafauna very rapidly
without any appeal to climate change.
Speaking of computer simulations, several talks put these to good
use. Bob Walters et al. showed the use of virtual skeletons in doing life
restorations, based on the Smithsonian's _Triceratops_ project. Don
Henderson's talk on ornithopod locomotion used reconstructions of walking
theropods and ornithopods to investigate the increasingly bird-like digit angle
in larger ornithopods. Emily Rayfield's Romer Prize session used Finite
Element Analysis to reconstruct the bite forces in _Allosaurus_: turns out, not
surprisingly, it is a lot weaker-jawed than _Tyrannosaurus_, and in fact the
cranium can absorb greater impacts if the mandible wasn't used. Emily
suggested that _Allosaurus_ may have used a hatchet-like attack, and then used
the slender mandible only in feeding: this is also the suggestion of Bakker in
the Gaia volume.
& Upchurch presented an interesting history of the identification of the
three sacrals in prosauropods, and how in some it is a dorsosacral, sacral 1
& sacral 2, and in others it is sacral 1, sacral 2 & a
caudosacral. Galton also showed how some workers had moved a bone from the
rear of the sacral series to the front (or vice versa) depending on their
team of Josh Smith, Matt Lamanna, Ken Lacovara, Jen Smith, and various
colleagues (including Peter Dodson) had a couple presentations concering the U
Penn work in Bajariya Oasis, Egypt. Their big (literally!) news is the
discovery of a titanosaur sauropod rivalling _Argentinosaurus_ in size, and
comparable in anatomy and stratigraphic position. They observed that the
likely local environment was a mangrove (which, as Lacovara pointed out, is
technically a type of environment rather than a species of plant: there have
been mangrove environments long before the evolution of red, black, and white
mangrove trees!). In the words of Thulborn and Farlow, back to the
swamps!! (They also did a calculation showing that, in the types of sands
involved in the channels, a giant sauropod would not get mired at all: this
stuff can support hotels!).
described "Sue": weird and wonderful stuff. In the words of Firesign
Theatre, "everything you know is wrong". Forget just about every
interpretation of the sex, pathologies, etc., that was made in the preliminary
reports of ten years ago: they were preliminary, after all, and only now has the
detailed work been done.
little Madagascan theropod with the vaugely spinosaurid-like jaw that Sampson,
Carrano & Forster had been showing around at SVP in years past turns out to
be a little abelisauroid. Additional material suggests that it forms a
clade with Argentine _Noasaurus_ and Indian _Laevisuchus_: in other words, it is
a noasaurid. Multiple specimens are known.
Speaking of abelisauroids, Coria et al.'s new abelisaurid is
magnificent!! It is very close to, but more primitive than,
_Carnotaurus_. The forelimbs are in great condition, and there seemed to
be no signficant carpals (if any): it looked like the metacarpals contacted
directly to the forearm!
Gishlick (presenting for Gauthier & Gishlick) has re-examined the hand of
_Compsognathus_. It turns out to have a relatively typical primitive
coelurosaur hand: very short mc I, long digit I, robust mc II, slender mc
III. He could not be certain if there was a third digit, but the end of mc
III suggests that one was present. He did show how confusingly things are
arranged on the specimen due to postmortem movement, so that the various
interpretations of Huene, Ostrom, Gauthier & Rowe, and others are
Thomas R. Holtz,
Department of Geology
Director, Earth, Life & Time
University of Maryland
College Park, MD
301-405-4084 Email: email@example.com
(Geol): 301-314-9661 Fax (CPS-ELT):