SVP DINO-PRESENTATIONS REVIEW (*VERY* LONG)

[Tetanurae@aol.com]

Hello everyone.  SVP 1997 is just about finished with, and now I am back here
to tell you all what went on.  Especially the good stuff.  Especially the
_Sinosauropteryx_ stuff, which I will put all last, even though it was spaced
sporadically throughout the last two days of the conference.  Note also that
I am only going to comment on the talks that I attended, which was not all of
them unfortunately, though I was at the same time, visiting the Field
Museum's collections (the ones they hide from the public I mean).  Also, I
would like to thank Maru Kirkaldy (sorry if it's misspelled) for organizing
the dino-liat breakfast, it was fun even though I arrived about 15 minutes
late :-P

So yes, on to the presentations:

DE KLERK et al presented some preliminray data on some new dinosaurs found
near Port Elizabeth, South Africa in Early Cretaceous sediments.  There are
the remains of an extremely small Iguanodontian that has teeth that seem to
be similar to something like _Camptosaurus_.  There is no anteorbital
fenestra present and the femur has a length of roughly 5 centemetres.
 Additionally there are some diplodocoid caudals and the nearly complete
skeleton of a small theropod that they think is a basal coelurosaur.

Two consecutive presentations by CARRANO and EGI (not together) showed data
that would indicate that mammals are better analougs for dinosaur limb
motion, rather than birds.

FORSTER presented a preliminary cladogram of the Iguanodontoidea that has
_Bactrosaurus_, _Telmatosaurus_ + _Lophothoron_, "Altirhinus",
_Ouranosaurus_, _Probactorsaurus_, _"Iguanodon" bernesarttensis_, and
_Iguanodon atherfeldensis_ as successive serial outgroups to the clade
Hadrosaurinae + Lambeosaurinae.  She has also redefined the clade
{_Hadrosaurus_ + _Lambeosaurus_} as Hadrosauridae, not Euhadrosauria as per
previous analyses.  This also excludes _Bactrosaurus_, Telmatosaurus_ and
_Lophorothon_ from Hadrosauridae proper.

NORMAN gave a preliminary description of "Altirhinus kurzanovi" as well as
presented a cladogram that was in sharp contrast to that presented by Forster
moments before.  "Altirhinus kurzanovi" is the in-press name that Norman is
going to give to the pancake-headed specimen previously (and incorrectly)
referred to as _Iguanodon orientalis_.  Not surprisingly.... his cladogram
had a monophyletic Iguanodontidae with _Iguanodon_ being the outgroup to the
glade {_Ouranosaurus_ + "Altirhinus"}.  _Probactrosaurus was the outgroup to
the Hadrosauridae.  Additionally, no matter how much he wanted to force it,
_Tenontosaurus_ could not be shoved into the Hypsilophodontidae :-) .  That
in fact, does not surprise me a bit, after looking at some teeth of
_Tenontosaurus_ the day before, they resembled, to me, gigantic teeth of
Dryosaurus_.

DODSON et al presented the first evidence of a titanosaur scute from
Madagascar.  If you haven't seen any material from Madagascar, do it.  The
stuff is absolutely amazing, it hardly even looks fossilized!  Anyways, this
scute has a highly vascularized outer surface, as well as a "woven" medial
surface with quite large vascular foramina.

CORRIA et CURRIE gave a talk on a new Theropod from the Rio Lamy formation
that looks similar to _Giganotosaurus_.  The tibia is about 100 centemetres
in length and there doesn't appear to be any sort of lacrimal horn.
 Additionally, there seems to be a "robust" and a "gracile" morph possibly
indicative of sexual dimorphism.

SAMPSON et al gave a talk on (yet more) material from Madagascar.  This time,
on some new, magnificent theropod skull material.  This is the stuff that was
previously referred to as _Majungasaurus_, but they are dropping that name in
favor of _Majungatholus_.  The reason for this is that the holotype specimen
of _Majungasaurus_ is an indeterminate lower jaw and cannot be positively
associated with the new material.  The _Majungatholus_ holotype however
definately belongs to this taxon.  The skull in lateral profile is roughly
similar to that in _Carnotaurus_, but differs in three areas.  First, the
upper jaw does not flare up quite so much, thus not giving it the fish-mouth
appearance of _Carnotaurus_, the nasals are very rough and thicker than in
any other Abelosaur, and lastly (and weirdest), instead of having frontal
horns, it has a big frontal spike right in front of the parietals.  This big
spike was the "dome" in the _Majungatholus_ holotype, and is diagnostic.
 THAT is why they refer this new theropod material to _Majungatholus_.  The
skull is also somewhat wider than that in _Carnotaurus_, and they suspect
that that is because _C_ has been crushed laterally (this might also have
given _C_ more of a fish-face than it actually had).

I missed Tom CARR's talk on Tyrannosaur ontogeny because I was running
upstairs to see Paul BARRET's talk on herbivorous adaptations.  Barret's talk
started early, so for all intents and purposes I missed both talks :-P

HOLTZ presented a preliminary phylogeny of the Tyrannosauridae.  At the base
there is a weakly supported clade uniting _Alectrosaurus_ and _Stygivenator_
(though refered to as _"Aublysodon" molnari_ in the presentation).
 _Alioramus_ is the next out group, then an unresolved trichotemy between
_Albertosaurus_, _Gorgosaurus_, and all other tyrannosaurs.  At the base of
the "all others" clade is _Daspletosaurus_, then _Nanotyrannus_,
_Maleevosaurus_, leeding to an unresolved trichotomy between _Tyrannosaurus
rex, _bataar_, and _efromovi_.  He also showed some slides, one of which gave
us the best image of _Albertosaurus_ to date - which is not much like
_Gorgosaurus_.  I will let him elaborate....

STEVENS presented the results of a study he did concerning binocular vision
in theropod dinosaurs.  He concluded that although many theropods had eyes
that faced outwards, they still had a fair amount of binocular vision, but
sometimes things like snouts, horns, and crests got in the way.

WILLIAMSON et SULLIVAN presented some info on a previously described specimen
of _Parasaurolophus cyrtocristatus_.  I did not understand many of the
slides, past the fact that the narial passages were very, very, very weird.

BAKKER presented evidence that indicated that _Nanotyrannus_ was actually the
*adult* form of _Tyrannosaurus_ (a tongue-in-cheek refutation of
_Nanotyrannus_ being sunk into _Tyrannosaurus_).  Additionally he presented
evidence that the American Morrison fauna was more diverse than previously
appreciated, ie two species of allosaurid (plus the announcement of a new,
complete skull of _Epantarius_), many species of megalosaurid, and the
referral of _Stokesosaurus_ to the (new) Monolophosauridae.  Bakker also
carried a large, articulated pathological allosaurid manus around in his
briefcase the entire session.  I have no idea what for.

UPCHURCH presented a new phylogeny for the Sauropoda.  His analysis shows
that _Vulcanodon_ is the most basal sauropod, then _Barapasaurus_.  He also
shows a monophyletic Euhelopodidae as the next closest outgroup to advanced
sauropods, though he expressed doubts as to its monophyly privately.
 Cetiosauridae is shown to be paraphyletic with _Patagosaurus_,
_Cetiosaurus_, and _Haplocanthosaurus_ serially closer to the Neosauropoda.
 Neosauropoda consists of a monophyletic Diplodocoidea with the crown group
Diplodocidae + Dicraeosauridae and _Rebachisaurus_ and Nemegtosauridae as
successive outgroups.  Oddly enough... his cladograms now agree with everyone
else' in placing titanosaurs as the sister group to Brachiosauridae, and
Camarasauridae as the sister taxa to that.  _Phuwiangosaurus_ from Thailand
is a tutanosaur more basal than _Andesaurus_ and _Opisthocoelocaudia_ is the
sister taxon to _Saltasaurus_.

WILSON's analysis I suspect was supposed to be a strong counter to Upchurch's
in his placement of titanosaurs, but instead, seemed to be nearly identical
to Upchurch's, except in the placent of _Nemegtosaurus_ and the monophyly and
placement of euhelopodids.  Wilson did synonymise _Nemegtosaurus_ an
_Quaesetiosaurus_, but did not go so far as saying they were the same as
_Opisthocoelocaudia_, however he does claim that _Nemegtosaurus_ is a
titanosaur.

CZERKAS presented evidence that supported the idea that _Stegosaurus) didn't
have cheeks, but instead a big turtle-like beak running the whole way up the
jaw.  He also reitterated his 1987 conclusion that _Stegosaurus_ had a single
row of plates *ontogenetically*, but later, as the animal grew, and the
plates got big, he admitted that they seperated off the midline to appear as
two rows of alternating plates.  Additionally, he insisted that the spikes
were held up at about 50 degrees instead of near-horizontal.

HENGST gave a talk about the evolution of dinosaur ribcages.  He indicated
that there was a transition in the ribcage morphology of dinosaurs that
supported the idea of airsacs in dinosaurs.  He indicated that by the
Jurassic, North American dinosaurs had achieved a stiff anterioir ribcage
that, but a mobile posterior one; ie the bases of the posterior ribs moved,
aiding in breathing like birds.  This was achieved by the Cretaceous in
Argentino dinosaurs.  He also presented evidence that ribcage-based
non-diaphragmatic breathing in dinosausr was just as efficient as
diphragmatic breathing in mammals (something to do with waterlogging rats
:-).

GALE gave a presentation that indicated that sauropods would need some sort
of non-narial vent in the trachea to facilitate breathing because, as he
claimed, there was too much dead space in the long trachea of _Diplodocus_ to
bring any oxygenated air into the lungs.  He figured this out by allometricly
scaling up a _Varanus_ to the size of _Diplodocus_ and taking measurements
from there.  He then suggested that instead of making the tracheal diameter
smaller, which would have too much friction, there were instead "vents," as
he called them, that were farther down on the throat analogous to the
embryonic gill arches of all vertebrates.  (NOTE: up until now I have not
editorialised any of these presentations, but I feel the need now)  This has
got to be one of the most abnormal presentations or suggestions that I have
ever heard in my entire life.  Upon reading the abstract the first time I had
misinterpretted his conclussion because it sounded so absurd and had thought
he was suggesting tidal volume to be the causal afctor in relocation of the
external nares etc...  I read it again.  This quickly became known as the
"sauropod tracheotomy" paper among people eager to find out what the heck he
was talking about by "vent closer to the lungs," and it became a running joke
to find hypotheses that would give you a vent in the lower neck (ie symbiosis
with dromaeosaurs...)....  I find his presentation flawed in so many ways I
can't even list them, the least of which is the fact that there are
pleurocoels in the way of his supposed vents....

JONES et al gave a presentation on dinosaur lungs.  They claimed that
dinosaurs had a hepatic-piston style lung system, where the plural and
abdominal cavities are seperated by an air-tight (fluid-tight is more
accurate) septum and the liver is pulled back by muscles anchored to the
pubes, thus creating a vaccum and inflating the lungs.  They also claim there
is direct evidence to support this in the fact that theropods and crocodiles
have similar pubes (when in truth, they don't), plus they claim that
_Sinosauropteryx_ has a visible septum.  Phil Currie disputes this, but more
on that later.  Additionally, they claim that the pubes of _Archaeopteryx_
are retroverted in a similar fashion to the of modern birds and that the boot
was the insertion of muscles originating on the tail that opperated air-sacs
in the post-pelvic cavity.  I suspect they also suggest that the pubic boots
in birds and non-bird tetanurans are convergent structures.  They conclude
that dinosaurs were ectotherms, there are no transitionals between a
hepatic-piston lung and an air-sac style lung, _Archaeopteryx_ and
enantiornithines were arboral, and the dino-bird connection needs to be
rethought in light of lung structure.

PAUL showed that the high-metabolism birds and mammals had long illia, and
that in contrast, reptiles do not.  The similar illia of dinosaurs could be
correlated to metabolic needs and maximum excercise capacity similar to that
in birds and mammals.  Additionally, the fact that many archosaur tracks show
fairly rapid walking speeds, plus the fact that many could fly also supposrt
the conclusion that they had high metabolisms.  To counter the previous
presentation on some few points, he shows that _Archaeopteryx_' pubis is not
very retroverted and the gut of _Sinosauropteryx_ is a mess.  He attepts the
use of an Extant Phylogenetic Bracket a la Witmer to demonstrate that basal
crocodilians had porrly developed hepatic piston lungs.  He cites many
features which would indicate that the earliest ornithodirans hadair-sac
style lungs, among them pneumatic ribs and vertebrae, short, rigid anterior
ribs, and long moveable posterior ribs with no lumbar region to speak of.
 Additionally, the earliest dinosaurs had pneumatic sinuses in their
vertebrae, indicating that they were not there for lightening of the
skeleton.  The end of his speech was rushed because he was running out of
time and I didn't take proper notes.  I'll let Greg elaborate on this info.

WITMER et SAMPSON investigate dinosaurs that had unusually large external
nares, such as macronarian sauropods, hadrosaurines and ceratopids by
investigating structures on living animals that are similar to those
suggested for these big nosed dinosaurs.  While the study is still in its
preliminary stages, there is some evidence to suggest that macronarians might
have had some sort of erectile tissue display device similar to that seen in
male gharials.

CHATTERJEE et ZHONG describe the wear facets on the teeth of _Shunosaurus_
and compare them to the teeth in other sauropods.  They also construct a
cladogram based on skull data which shows that titanosaurs and diplodocoids
are sister taxa and call that group Homolasauropoda (actually named by
Janensch in the 20's).  They suggest that homolasauropods fed on softer, low
lying plant materials based on jaw musculature and tooth wear facets.

HAPP et MORROW describe the skull of a subadult _Triceratops_ that shows
signs of tooth marks.  The claim that the animal was killed by a crocodile
because there are deep gouges made by crocodile teeth on the postorbital
horn, perhaps indicating a struggle.  There is also evidence that suggests
that the carcass was scavenged by tyrannosaurs, dromaeosaurs and
multituberculates.

GOODWIN et al describe yet another tiny _Triceratops_ skull with most of the
posterior elements preserved.  The parieto-squamosal frill is scalloped
extensively and shows that the exoccipitals of the adults are not homologous
to the scalloped edge in the babies.  The entire reconstructed skull is very
short in the snout and has rather substantial postorbital horns already
developed.  It is very cute.

ZHOU describes some birds from Liaoning and supports the basal bird dichotemy
Sauriurae + Ornithurae.  _Confuciusornis_ has a long ungual claw on manual
digit I and is claimed to retain a jugal-postorbital bar.  Additionally,
_Gansus_ is said to have a pedal claw morphology similar to that of puffins,
perhaps supporting some sort of webbing.

PADIAN explained how there is no positive evidence to support the idea of
arboral origins of bird flight.  He additionally said "Pining for the lagoons
of Solnhoffen" a la Monty Python while a slide of _Archaeopteryx_ was being
shown.

MADISON presented a study of limb analysis based on lifestyle, and not
phylogeny, that eventually showed that (surprise, surprise) _Hesperornis_ was
most similar to limb-propelled divers and (now this is a surprise),
_Ichthiornis_ is most similar to flying ground-birds like chickens and (more
closely) tinimou.

CLARK et al describe a new species of _Dimporphodon_ from Mexico that
confirms, among other things, that the foot in pterosaurs is plantigrade and
there was very little movement in the joint between the foot and the toes.

UNWIN described some features in _Tupaxuara_.  He indicates that pterosaurs
had very narrow acetabula and femora that facilitated a wide range of motion.
 He also suggested that pterosaurs used their hindlimbs in tandom with the
forelimbs in flapping.

PETERS suggested that pterosaurs are in fact derived prolacertiformes closely
related to _Cosesaurus_ and _Sharovipteryx_.  Additionally he suggested that
the trackways assigned to _Rotodactylus_ belong to a _Cosesaurus_-type
animal.  _Germanodactylus_ apperently paraphyletic, with _G. rhamphistinus_
closer to a clade containing: _Pterodactylus_, _Pterodaustro_,
ctenochasmatids, and azhdarcids, and _G cristatus_ closer to the remaining
pterodactyloids (_Nyctosaurus_, _Pteranodon_, tapajarids and
dsungaripterigids).

Now the cool stuff:

GEIST et al suggest that the impressions preserved with _Sinosauropteryx_ in
fact support a sea-snake like fin on the tail.  One good point I will give
them is the statement "they aren't feathers just because you want them to
be."  They shoot themselves in the foot though, with the suggestion (without
personal examination) that they in fact support a sail, citing bad photos of
a dissected sea snake tail that is dissimilar to the structures in
_Sinosauropteryx_.  It could be countered with "they're not *not feathers*
just because you don't want them to be".

SCHWEITZER gave an amazing talk on protein presserved with the flying raptor
and _Mononykus_.  She recovered proteins that were homologous in structure
and chemistry to the beta keritan claw sheeths of modern birds.
 Additionally, she showed quite conclusively, that _Mononykus_ had some sort
of hollow beta keritan tube like structure, probably homologous to the
central rachis of bird feathers.  The protein data is very good and indicates
that the structures were entirely beta keritan, which is only seen in
feathers.  The SEM photo she showed of one of these structures was VERY
similar to a photo of a turkey vulture neck feather.

Lastly, CURRIE gave an impromptu talk on _Sinosauropteryx_ yesterday
afternoon with the title "_Sinosauropteryx_: proto-feathers or quill?"  He
confirms many details of the creatures anatomy, for instance it had a three
fingered manus, with a very long ungual claw on manual digit I, it is said to
equal the radius in length.  Digit I is almost nearly the length of digit II.
 He demonstrated that the structures are not in the dorsal midline, the are
soft and pliable, and they are not imbedded within the skin.  The covering is
apperently not of uniform thickness, and forms a 'corona' around the specimen
similar to that seen in _Confusciusornis_ found in the same area.  He also
confirms that the structures are indeed hollow and seem to suggest a
clumping, then brabching structure by way of camera lucida diagrams.
 Additionally, there are structures that are seen between ribs number 6 and
7, behind the ulna and near the tibia.  He also indicated that Geist et al's
suggestion that the structures were between the haemal arches, in fact
indicates that they were behind them because muscles are between them, not
sea-snake sails.  He additionally counters the argument that it was aquatic
because the tail 1) has short neural spines and haemal arches 2) the
vertebrae's transverse processes were weak and show a limited range of motion
3) the neural spines and haemal arches were not the same length, giving the
tail assymetry not seen in tail propelled animals, 4) the "sail" is taller on
the top of the tail than on the bottom 5) _Sinosauropteryx_ is a rare
component of an aquatic fauna, which is opposite of what you would expect
with a cpmpletely aquatic animal 6) the stomach has terrestrial remains in it
(turtle and mammal) and 7) it is a bipedal cursor.

All in all great fun.  They also had the flying raptor, _Majungatholus_, and
_Archaeopteryx bavarica_ (the real thing) on display at the Field Museum.  No
Sue yet........

Pete Buchholz
Tetanurae@aol.com

"There're some other people there, they're not paleontologists, but they're
useful to have around."