Personal Account - Darren Naish
This account is based on a posting on the Dinosaur Web ring. It is more or less un-edited, though I have added links to images.- RF
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).
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.
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.
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 reevaluation. 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.
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. This is Isanosaurus, the new taxon just described in Nature.
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.
'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.
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.
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).
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.
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.
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.
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.
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).
Sharovipteryx: what can it tell us about the origin of pterosaurs.
Sharovipteryx is more pterosaur-like than previously noticed: there is a patagium between the femur and thorax and there are aktinofibril- like rods in the patagia that are IDENTICAL in size, shape and form to aktinofibrils of pterosaurs. The femur is longer than the tibia, there are elongate caudal verts and there are 4 sacrals. The foot is pterosaur-like, the neck is long. Lots of nice photos. In parsimony analysis, Sharovipteryx is a prolacetiform closest to Macrocnemus. Unwin ran David Dilkes' archosauromorph data set and included pterosaurs: they are prolacertiforms in a clade with Protorosaurus, Macrocnemus and Tanystropheus (and Tanytrachelos IIRC). Unwin thus supports the idea that pterosaurs are prolacertiforms and NOT archosauriforms.
Pterosaurs, flying machines and the first 'bottom deckers' in the world.
new Crato Fm azhdarchid - this is the same specimen that preserves complete feet and has strongly curved unguals and a scaly food pad (discussed at SVPCA in Edinburgh last year) - has proved strikingly complete and well preserved. The whole of the wing and leg (from at least one side) are there. It is STRANGE. Legs are very very long, wings proportionally short. The scap-coracoid is constructed such that the glenoid is very low down in position (no they do not have it the wrong way up) and the wings would have been positioned very low on the body. Dino explained at great length the difference between 'top decker' and 'bottom decker' aircraft: 'bottom deckers' are difficult to fly, more manoeuvrable but unstable. Azhdarchids (or at least this new taxon) seem to have been able to hold the wing in a shallow V and thus confer great stability during flight. The abstract is lengthy and there is a lot of aerodynamic discussion that I will not recount here. This morphology is unique for flying vertebrates.
Internal helical reinforcing of the pterosaur wing skeleton.
X-shaped cross-bracing inside pterosaur long bones is a method of internal reinforcing. Cross-struts in long bones are remodelled during life.
The cheek of it: the skull of the plesiosaur Muraenosaurus... revisited.
New specimens and interpretations allowed Mark to update the skull reconstructions he'd produced in 1997 and 1999. A new specimen is large and chunky: bigger (about 1.5 times) than previous specimens. Individual variation or a new species? New specimen includes cheek region (previously unknown) plus parts of suspensorium, lower jaw, frontals etc. Muraenosaurus is no dainty slim-headed predator: its skull is deep and quite robust with a prominent sagittal crest and a peculiar 'broken nose' effect on the frontals (a rugose bump rostral to the orbits, dorsal to nares). This is not an artefact (is present in other specimens). Not mentioned in the talk was the fact that the external nares are rostral to the internal nares (reverse of condition now well known for plesiosaurs). Despite the large size of the new specimen, it was less well grown that the other, smaller specimens! In many respects Muraenosaurus is identical to cryptoclidids.
Pachycostasaurus dawni, a Callovian pliosaur (Reptilia, Sauropterygia):
is the new genus a juvenile?
Les showed lots of slides of the skull and how he'd managed to reconstruct it. It is not a juvenile of a named pliosaurid taxon.
Plesiosaur necks, service cores and statistics.
Inspired by Ken Carpenter's recent elasmosaurid phylogeny papers, Richard took issue with some aspects of cladistics. Am a bit bored with these kinds of debates so will say no more.
Phil Manning: New discoveries in the Yorkshire Jurassic.
Dig at Kettleness, near Whitby, has yielded new ichthyosaur species. I was on this dig.. though I didn't actually do any digging. Also new dinosaur tracks and previously unnoticed Scelidosaurus material found in the collections of a Yorkshire museum (possibly Whitby). The material was collected in the 19th century. What will interest Jim Kirkland (hint) is that the material - a few caudal verts - had the scutes preserved in the GSP style (i.e. scutes stick up vertically from dorsal surface: do not project laterally).
A 23 m ichthyosaur from the Upper Triassic of Canada.
Yes, 23 m. That is not a typo. First reported by an archaeologist looking for Amerindian burial sites and then reported to the Tyrrell, the specimen has not been easy to excavate and some deforestation has occurred. Skull is more than 5 m long with enormous supratemporal fossae which are floored with bone, pierced by tiny foramina. Very odd. There is a slight tailbend preserved but there are no wedge-shaped centra. Is not Shonisaurus, not does it seem to be a shastasaur. Gigantic ichthyosaurs thus evolved in the Carnian-Norian and appear to have died out at the end of the Triassic (but there are Liassic giants, not mentioned by Makoto). Utatsusaurus is now known from Canada, suggesting biogeographical link across Panthalassian Ocean.
Still have synapsids, parareptiles and lepidosauromorphs to go. In view of my previous comment (about theropods being the new rodents), recently found the following quote. It was written by Robert Wilson, a prominent rodent worker, in a tribute volume on rodents:
"I still remember my first meeting with Richard Swann Lull when I came east to study Bridger rodents at the Yale Peabody Museum. I was ushered into his august presence by Nelda Wright, and after the usual exchange of pleasantries, Professor Lull volunteered that he only knew two things about rodents, that they all looked alike, and that they never changed! Dinosaurs and mice and the twain shall never meet I suppose, but the meek, as now based on numbers of workers, seem about to inherit the earth" - - - R.W. Wilson, 1989.
Though SVPCA meetings have traditionally not ever been written up, meaning that the contents have remained mysterious to those unable to attend, it looks likely that the Dinosaur Society will do a write-up, and that this will appear in the next issue of the Quarterly Review. I say this as I have just gotten hold of vol. 3 no. 5 of The Dinosaur Society's Quarterly Review (from earlier this year) and it has a two page report on the 47th SVPCA (Edinburgh, Sept. 1999). I don't know what the status of the American Dinosaur Society is - has it died? - but the UK version, under the supervision of Jeff Liston, Arthur Cruickshank, John Martin and Dougal Dixon, has returned with a renewed vigour and is definitely worth getting involved with.
Returning to the 48th SVPCA, I have remembered various other archosaur and marine reptile presentations that I forgot to mention last time. This is mostly because some were posters, not talks. They are still worth mentioning however.
Some functional aspects of the skull of the South American horned theropod
Carnotaurus sastrei (Saurischia: Theropoda).
As per Bonaparte et al., Mazzetta argued that Carnotaurus had a highly kinetic skull and could gape widely to swallow large objects. A prokinetic hinge rostral to the orbits would have allowed (as in birds) elevation of the rostrum while the eyes could remain fixed on prey. RFTRA was used to compare Carnotaurus with Ceratosaurus: the former had vaulted its skull for a fast, rather than strong, bite. Carnotaurus was envisioned as an active predator of fast, small prey. I never got to meet Mazzetta and wanted to ask how confident he was that the type skull of Carnotaurus is not distorted: Goodwin et al., in their initial presentation on Majungatholus, suggested that the deep and narrow skull shape of Carnotaurus owed itself to compaction and might not have been natural. Also, I'm a bit sceptical of cranial kineticism in this animal (though I only have the monograph to go on and haven't examined the specimen).
A new monograph of Dimorphodon.
Sarah is working on remonographing Dimorphodon - both Owen's and Padian's works have some conspicuous misinterpretations and reconstructions that differ from what is really seen in the material. A new skull reconstruction was shown.
M. S. Arkhangelsky:
Ichthyosaurs of the Volga region (Russia).
Sadly Arkhangelsky did not attend, so no talk or poster. But it's worth recounting some of the stuff it says in his abstract because there are quite a few new names. Ophthalmosaurus calloviensis, named by Arkhangelsky in 1999, is a new species from the Callovian of Saratov based on a paddle. The new family name Undorosauridae Efimov, 1999 is used for a group that includes undorosaurines (including Undorosaurus Efimov 1999 and Plutoniosaurus Efimov 1997) and platypterygiines. However (this is my comment, not Arkhangelsky's), Platyptergiinae was erected by Bardet in 1994 so Undorosauridae should really be called Platypterygiidae. Among other things, Arkangelsky regards Yasykovia Efimov 1999 as a junior synonym of Paraophthalmosaurus.
Moving onto more talks...
GASTROPODS Stick with me here.
Dave Martill and Mike Barker:
The dinosaur and the snail.
Several Wessex Fm dinosaur bones from the Isle of Wight have strange little rounded bodies arranged in patches on their surface. The bodies are all the same size and arranged in crude rows. It turns out that they are gastropod eggs with embryos still inside. So, Cretaceous gastropods were using dinosaur bones as nesting substrates.
The Lower Triassic 'lizard' Colubrifer: a reassessment.
Colubrifer, described in 1982 by Carroll as a reduced-limb squamate perhaps ancestral to some of the later reduced-limb groups, cannot be shown to be a diapsid. Carroll's interpretation of the skull elements is questionable and what he regarded as the dorsal midline of the skull is suspect. Reidentification of some of the skull elements showed that the skull was parareptile like, specifically like Owenetta, and the proportions of the skeleton matched described specimens of Owenetta exactly. Robert Reisz said that he had independently come to the same conclusion while looking at Colubrifer for a recent review.
A helodermatid-like lizard from the basal Cretaceous of England.
As part of the review of the Purbeck fauna, Paul was asked to look at the 'granicones' previously described as part of Nuthetes, Echinodon or a stegosaur. Histological analysis, carried out by Jane Clarke, shows that the elements have similarities with the osteoderms of thyreophorans, squamates and anurans but they are clearly not from crocs or turtles. Closest similarity is with the cranial osteoderms of helodermatids and this appears to be the best identification for the elements. If correct this is the earliest helodermatid lizard to be reported and the first from the UK. Showing cladograms that include Gao and Norell's Monstersauria always incites a few sniggles.
Short review of the Middle Eocene (MP 13) lacertilian fauna from the fossillagerstatte
Geiseltal near Halle (Saale), Germany.
Corytophanid iguanians are well represented at the locality (not sure what this means for biogeography: another group shared between Eocene Germay and S. America? I'm not aware of corytophanids from elsewhere) and there are also possible skinks and lacertids, a cordylid and both glyptosaurine and anguine anguids. The corytophanids are part of the messelosaurine subfamily, erected by Torsten in _N. Jb._ recently.
A history of snake retinas.
Booids, viperids and colubrids have different retinas but the colubrid type appears to have been derived from the viperid type, not the other way round as Wall, encouraged by the snake systematists of the time, concluded. This work is in agreement with Underwood's other work: all suggests that venomosity was primitive in caenophidians and that colubrids are not primitive in lacking venomosity and grooved teeth - they are derived. Structure of the snake retina cannot be derived from any lizard retina.. dammit, should have asked an intelligent question about amphisbaenians:)
Patterns of amniote diversification during the Late Palaeozoic..
Essentially, 'synapsids did it first'! Cladograms of all Palaeozoic amniote genera show that both synapsids and reptiles underwent three or more major events of diversification but, on each occasion, synapsids evolved more taxa than reptiles. This is not due to a size bias or misrepresentation due to environment. While reptiles are very abundant at some localities (e.g. Bromacker quarry in Germany where there are loads of procolophonids) they are at a lower diversity than synapsids. Slides shown of the new ?bipedal bolosaurid, the earliest known facultative biped (posters at SVP in 1997 and 1999, was also covered in Nat. Geo.)
Gorgonopsid ecomorph niche-filling after the P-Tr extinction by 'aeleromorph'
moschorinid therocephalians: a finite element approach.
As it says. Moschorinids have robust, well-braced palates and felid-like incisor arrays and effectively mimic the earlier macropredatory gorgonopsids and appear to have replaced them ecologically. One problem is that gorgonopsids lived alongside large prey animals like giant dicynodonts and pareiasaurs - in the faunas from which moschorinids are known there are no large prey animals.
I have a speculation. Could it be that, rather than attacking large animals, moschorinids were either (1) biting armoured prey (e.g. small parareptiles) or (2) biting the skulls, rather than the bodies, of small/medium-sized prey? Jaguars (Panthera onca) are reported to have the most robust skulls of any extant felid and (1) they eat armoured prey like caimans and turtles and (2) kill medium-sized prey, like capybara, by biting through the orbit or braincase. Unlike moschorinids however, jaguars often have significant tooth wear to the extent that some individuals have their canines worn down to broken stumps. Oh well.
Another look at haramiyids.
A good review of haramiyids: apparently they are now known from Tendaguru and thus survived for longer than thought. Theroteinus has three rows of cusps on molars and appears not to have the longitudinal chewing present in other forms. MTBs and haramiyids appear to have similar premolars and Butler argued both that haramiyids should be allied with MTBs and that both are very basal mammals that should be recognised as the Allotheria. This is the old school view of course.
Sanchez-Villagra argued that argyrolagids were part of the Paucituberculata,
Janis covered the evolution of pacing locomotion in camels.