[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

SVPCA 2000, part 1



Am now back from the 48th Symposium of Vertebrate Palaeontology 
and Comparative Anatomy. This year the venue was here (Portsmouth) 
which made travelling a bit cheaper. Thanks to organisation by Dave 
Martill and Stig Walsh, this SVPCA was perhaps the most visually 
impressive ever with a display of Luis Rey artwork, some of the 
models from Walking With Dinosaurs (_Ophthalmosaurus_, 
ornithocheiroid and _Koolasuchus_ head), an unbelievable display of 
Santana and Crato Fm. fossils (including coelacanths and a complete 
notosuchian) and a full skeleton of a new taxon of robust Liassic 
plesiosaur. Isle of Wight collectors Mick Green and Keith Simmonds 
brought along some stuff for display. Keith showed a complete 
sauropod forelimb - it is one of four forelimbs (from two individuals) 
found preserved vertically in the substrate. Apparently two same-sized 
individuals (siblings?) got mired together and both died standing up. 
Discussing the specimen with Paul Upchurch, it seems to be a non-
macronarian eusauropod (yes, Upchurch does use the term 
Macronaria) with proportions suggesting it's even more basal than 
_Cetiosaurus_. So... cf. _Jobaria_?:)

As always there was much socialising and parties that went on until 2, 
3, 4 or 5 o'clock (depending on stamina and lack of regard for personal 
health). The T-shirts featured my design (our new theropod, see below).

Was great to meet some new people for the first time (e.g. Adam 
Yates, who you might have heard of). Talks and posters were 
dominated by archosaurs with a substantial contribution from marine 
reptiles, squamates and other diapsids. Fish were the losers with 
something paulty like four talks - mammals were similarly ill 
represented. I think I'll make a T-shirt that says "Theropods are the new 
rodents". Personally I like mammals as much as reptiles and I'm not 
happy to see groups underrepresented. Right now I cannot find my 
abstract volume so am going to try and recall the presentations off the 
top of my head. Where to start? Will review the conference in more 
than one email. This is Part 1, the dinosaur one.

DINOSAURIA

Max Langer: Postcranial anatomy and the diagnosis of Dinosauria.

Discussion of all the characters previously used to support dinosaurian 
monophyly showed that, in Max' new tree, many of them (e.g. 
additional of sacrals, fully open acetabulum) have evolved 
independently in different dinosaurian clades (but dinosaur monophyly 
still supported). Herrerasaurids were not theropods but whether 
_Eoraptor_ was the sister taxon to Herrerasauridae or to 
Herrerasauridae + Eusaurischia was controversial. _Guibasaurus_ was 
sister to other theropods. As an aside, in the theropod tree 
Coelophysoidea was paraphyletic because _Dilophosaurus_ was closer 
to _Ceratosaurus_ + Tetanurae than to _Coelophysis_. I think Ollie 
Rauhut has this result as well. Lots more stuff but I wouldn't like to 
say without checking Max' abstract.

SAUROPODOMORPHA

Adam Yates: Whither Sauropoda? New data from a British 
'prosauropod'. 

Adam argued for a paraphyletic Prosauropoda where sauropods were 
part of a clade that included _Lufengosaurus_ and _Massospondylus_, 
_Melanorosaurus_ and _Blikanasaurus_. Much new data from a new 
small _Thecodontosaurus_ specimen, probably a new species, has 
allowed major reevalution. Skull reconstruction of new _Theco._ 
superficially much like _Eoraptor_. Hmmm. Adam has covered some 
of this in DML emails and can obviously do a much better recap than I.

Eric Buffetaut: Triassic sauropods from Thailand.

New genus of Triassic (yes, Triassic) sauropod from Thailand: 
includes material previously described as prosauropod. The femur is 
the main reason for thinking that the animal is a sauropod - the fourth 
trochanter is reduced and peculiar in shape. There is also a huge 
humerus from a different site that might be from the same taxon. 
Surprisingly, all of the material is huge and suggests an animal of 6-7 
m length. 

Kent Stevens: Digital models of joint articulation.

Much discussion of how one models zygapophyseal articulations on 
the computer. Sauropods essentially have three different ways of 
evolving zygapophyseal articulations in the neck. At previous 
presentations, Kent has shown neutral neck poses for euhelopodids and 
brachiosaurs. This time it was the turn of _Dicraeosaurus_: in Kent's 
model, the dicraeosaur neck goes down and the head is nearly touching 
the ground. The sauropod thus looks like a grazing bovid.

THEROPODS

Angela Milner: 'Little and large' - theropods from the Purbeck.

The _Nuthetes_ teeth are most like those of dromaeosaurids. There is 
also a partial metatarsal from the Purbeck that agrees in some features 
with metatarsals of dromaeosaurids.

Darren Naish: An enigmatic new coelurosaurian theropod from the 
Early Cretaceous of the Isle of Wight.

A new specimen of long-legged gracile coelurosaur from the Wessex 
Formation is not synonymous with any of the named Wealden Group 
theropods(nor with any other named taxon) and is a new taxon of 
coelurosaur . It lacks derived features allowing allocation to any 
recognised coelurosaurian clade but there are some similarities with 
tyrannosaurids. Could it be a near-tyrannosaurid? Has fused nasals, a 
distinctive maxilla and a proportionally short premaxilla. Arms are 
long but powerful. Though the specimen is 4-5 m long, it is not an 
adult.

Emily Rayfield: Muscles, mobility and jaws: more finite element 
analysis of theropod skulls.

FEA of _Allosaurus_ shows that it had a relatively weak bite. Of 
course there was more to the presentation that this but I don't 
understand physics enough to repeat any of it. Emily showed photos of 
'big Al': this specimen has an apparently very shallow lower jaw.. this 
could be in agreement with the weak bite hypothesis (this is my 
speculation, it wasn't mentioned by Emily).

Don Henderson: Show some backbone! Axial body mass distribution 
and differing support strategies in theropod and ornithopod dinosaurs.

Don started his talk by stating his regret at involvement in the recent 
_Nature_ paper: he only did the calculations and, quote, "Birds are 
dinosaurs". Theropods and ornithopods have different ways of 
supporting body mass. 

Paul Davis: Fun with dinosaur fluff: interpreting Mesozoic feathers.

Paul claimed that _Archaeopteryx_ and _Confuciusornis_ only 
provide evidence for contour feathers: no filoplumes or down. Also,  
all but the very latest Cretaceous isolated feathers are contour feathers. 
I believe this is wrong. I'm also troubled by the fact that Paul started 
his talk by excluding nonavians - they cannot have feathers because 
they are not birds. Paul also showed his 'alternative' avian phylogeny 
(has been mentioned on this list before). It is controversial and strange 
because avisaurids and a few other enantiornithines group with 
_Patagopteryx_, hesperornithiforms, ichthyornithiforms and 
neornithines: not with other enantiornithines. Gareth Dyke was 
unhappy about this and asked for the data - Paul said it would be 
provided in due course.

Gareth Dyke: _Protornis_ and the concept of 'centres of origin' in 
Tertiary palaeornithology.

Due to festivities the night before I missed this talk (and the following 
one) but I did steal Gareth's overheads. Olson and other authors have 
argued for the presence of some (modern) Southern Hemisphere bird 
groups in the Eocene of Europe. Among these are various 
caprimulgiforms, motmots (momotids) and, most recently, magpie 
geese (anseranatids). Cladistic evaluation does not support some of 
these identifications. The supposed European motmot (_Protornis_) is 
a coraciiform, but apparently outside of the group including meropids 
and motmots. The London Clay anseranatid is an anseriform but not an 
anseranatid. I gather from the overheads that there was some 
discussion of coraciiform monophyly but I don't know what the 
outcome was.

Stig Walsh: Big chested birds - exciting new avian material from the 
Neogene of Chile.

The first pelagornithid coracoid to be announced to the community 
(though others are apparently known, they are secreted away in 
collections and nobody is working on them). Is huge and has features 
intermediate between pelecaniforms and procelariiforms. I missed this 
talk and what I say here is taken from conversations I've had with Stig 
about the bone.

ORNITHISCHIANS

David Norman: A new dinosaur from Transylvania.

A new genus has been recovered from material previously assigned to 
_Rhabdodon_. Most of the postcrania seems to be of 
dryosaurid/camptosaurid grade but the skull is distinctive: this is an 
ornithopod trying to be a ceratopian (sort of). Posterior part of skull is 
rather flattened dorsoventrally, there is a distinctive step in the lateral 
side of the predentary as there is in dryosaurids. Ischium lacks an 
obturator process, which is strange. On the cladogram the new taxon 
fits between _Tenontosaurus_ and Dryosauridae. Intriguingly, the 
cladogram Dr. Norman presented is pretty much a contradiction of 
everything he's been saying for the last few decades: Iguanodontidae 
was paraphyletic and _Tenontosaurus_ (which was monophyletic) was 
closer to higher iguanodontians than to _Hypsilophodon_. 
_Iguanodon_ (atherfieldensis + bernissartensis) was a clade and 
_Altirhinus_ and _Eolambia_ grouped together. The new name 
Thescelosauria was used for (_Thescelosaurus_ + _Bugenasaura_) + 
Hypsilophodontia. Hypsilophodontia = _Hyp._ + _Tenontosaurus_ + 
new taxon + Dryomorpha (Norman did not, and generally does not, use 
latter name). 

That'll do for now. More to come if I have the time.

"I know the real world exists, I see it after 7 pm, but during the day I'm 
in a different world, and I don't want to leave it"

DARREN NAISH 
PALAEOBIOLOGY RESEARCH GROUP
School of Earth, Environmental & Physical Sciences
UNIVERSITY OF PORTSMOUTH
Burnaby Building
Burnaby Road                           email: darren.naish@port.ac.uk
Portsmouth UK                          tel: 01703 446718
P01 3QL