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

PROG. PAL. '99

I return from Progressive Palaeontology '99, this year held at 
Bristol University's Dept. of Earth Sciences. Hats off to Trevor 
Cotton, Aaron O'Dea, Lucy McCobb and Gareth Dyke for organising a 
very enjoyable conference. Free wine was provided (good move) and we 
all enjoyed the evening in the pub. The meal at the pizza place was a 
bit raucous: still, the shouting may improve my singing voice (not 
that I have one)

Talks were diverse and vertebrates were VERY well represented. It was 
implied that this was due to Bristol's strong vert. palaeo. 
department, but I reckon that most or all of the vert. palaeo. 
students would still have turned up had the venue been elsewhere. 
Here are summaries of the vertebrate talks (for full abstracts, see 
the www site (http://palaeo.qly.bris.ac.uk/pp99/fhome/htp) or the 
abstracts volume (citation at bottom).

Byron BLESSED (Brisol) discussed new work he has done/is doing at the 
Cromhall Quarry: a late Triassic karstic deposit within Carboniferous 
limestone. Traditional interpretation of this site is that it 
represents filled-in fissures but Byron argued that they may in fact 
have been true cave deposits. Taxa represented include hybodonts, the 
rhynchocephalian _Gephyrosaurus_ , sphenodonts, 
kuehneosaurids, little crocodylomorphs, and bits of 
_Thecodontosaurus_. He figured a MAMMAL MOLAR (the first for 
Cromhall): was suggested that it could be morganucodontid, but I 
couldn't see the inflated cingulum that is (IIRC) diagnostic for this 
group. Microvertebrates are cool but then, as I just spent time 
picking sand grains off a 4 mm lepidosaur maxilla, I suspect this 
opinion is due to novelty value (novelty for >me<, you understand).

Michael BONIFACE (Bristol) reinterpreted_Isalorhynchus genovefae_, a 
Madagascan rhynchosaur described by Eric Buffetaut in 1983. Michael 
suggests that some of the elements referred to this taxon are 
actually from trilophosaurs (Is this a new locality for 
trilophosaurs?), and that derived characters seen in the _I. 
genovefae_ material (maxilla and astragalus) show it to be up in the 
_Scaphonyx_-_Hyperodapedon_ clade. It was in fact intimated from the 
cladograms presented that _I. genovefae_ was a member of 
_Hyperodapedon_, but I may have misinterpreted something.

Leslie NOE (Derby) spoke about pliosaurid skull morphology and what 
it might reveal about diet AND inferences we can make on salt 
secretion in these marine reptiles. Hooray, another skull 
reconstruction of _Simolestes_. Leslie suggested that it appeared 
suited for cephalopod feeding, but this is controversial and I know a 
few workers who think otherwise. IF such animals were invertebrate 
feeders, they were consuming isotonic prey items that bought a high 
salt load into the body; to get rid of the salt, plesiosaurs simply 
must have had salt glands. Makes sense to locate these somewhere 
around the orbit. Comparisons with sea turtles are infinitely 
valuable, and it was suggested (by Clive Trueman, a 
pathology/taphonomy expert) that oxygen isotope analysis (i.e. as 
preserved in the pliosaur's teeth) could be informative as to diet. 
As I pointed out, exactly this kind of work has been done by 
Thewissen et al. on protocetoid whales (except these workers were not
looking at diet, but whether or not the whales drank sea or 
fresh water).

Stig WALSH (Portsmouth) discussed the bird fossils from the new 
Neogene bonebed he is working on from north-central Chile. Scrappy 
but nevertheless diagnostic elements reveal that presence of 
pelecans, cormorants and a mollymawk-sized _Diomedea_ in the region 
at the time (late Mio-early Plio). These are all either the earliest, 
or the most southerly, of their respective groups in the South 
American fossil record. Bit bigs of carpomet, tarsomet etc reveal the 
presence of a pelagornithid in the deposit. This is excellent news 
should Stig get an artist to do a restoration of the fauna:) 
Pelagornithids are big, amazing long-winged seabirds with serrated 
jaw margins, if you don't know. They are horrendously understudied. 
The commonest bird in the assemblage is a medium-sized penguin. It's 
so common there may have been a breeding colony at the site.

Emmanual FARA (Bristol)  spoke about 'filling the gap': the supposed 
depauperate fossil record of Cretaceous tetrapods. Molecular 
biologists (Hedges etc.) assert that pretty much all extant higher 
bird and mammal taxa evolved in the Cretaceous, but their fossil 
records do not show this. What does the quality of the Cretaceous 
fossil record have to say about this? Well, the Cretaceous is bad, 
but... it's not **that** bad, and in fact bits of it (especially 
latest Cretaceous) are comparatively good. Indicates that the 
sampling is good enough to show that some of this proposed bird and 
mammal diversification is post-Cretaceous, as often implied by 

Marco SIGNORE (Bristol)  gave a run down on new research on 
_Scipionyx_. With its fully ossified forelimb skeleton, Marco 
suggested that Scippy was a precocial baby, and that it and other 
'maniraptoriforms' (I put the term in quotes as it is irrelevant here 
whether we are talking about a clade or a morphotype) were grasping 
predators that lack any analogue in extant Tetrapoda. PREYING MANTIDS 
and, perhaps, mantis shrimps, are his analogues. Not a new idea round 
these parts, and quite a good one I think. The guts of Scippy reveal 
the villi, and that the guts were apparently entirely 
gastralia-supported, and not propped up by the pubis. Again, where is 
the stomach? Little bits of mineralised tissue in the stomach region  
might be ingested grit, and not fragments of prey bones as previously 
suggested. The big, amorphous reddish stain in the ribcage was again 
regarded as a very large liver. Controversial, of course. And in 
respiration, Marco favoured the hepatic piston system. I must admit I 
am not so sceptical given that Marco insists that birds are still 
theropod dinosaurs and, after all, members of the bird lineage must 
have evolved their air-sac system from hepatic piston breathers at 
some point in amniote history (seeing as amniotes are, primitively, 
hepatic piston breathers).

Marco mentioned that Italy has recently yielded another dinosaur: a 
hadrosaur apparently.

Darren NAISH (Portsmouth) spoke about the tangled taxonomy of 
_Calamospondylus_ and _Aristosuchus_. Tedious stuff, and I can't be 
bothered to write it up. Unless people really want me to. My 
conclusion is that _Calamospondylus_ and _Aristosuchus_ are not 

Emily RAYFIELD (Cambridge) gave a superb presentation on Finite 
Element Analysis as applied to the skulls of three theropods: Stan 
the _Tyrannosaurus rex_, _Allosaurus fragilis_ and _Coelophysis 
bauri_. Theoretical bite forces were applied to 2-dimensional mesh 
models of these skulls. In the _T. rex_ skull, Emily created two 
kinetic jones (max-jugal and jugal-postorbital contacts), and in this 
model, stress dissipation followed a different pattern from a 
non-kinetic skull. There is an awful lot to all of this, and much of 
it is pretty complex and has some fascinating implications for 
theropod skull morphology and feeding/killing behaviour. At the fear 
of not doing Emily and her work justice, I will refrain from citing 
any more details.

Huw BOULTON (Bristol) discussed his work on the Karabastau Formation 
(Upper Jurassic) of Kazakstan. Represents a lake: 
Konservat-Laggerstatten with paper-fine shales. Very interesting 
tetrapod fauna: Huw showed slides of pterosaurs _Sordes_ and 
_Batrachognathus_, the basal urodele _Karaurus_, the little 
Karabastau Fm croc whose name I can't remember, and the putative 
feather _Praeornis_ (regarded by Nessov as a junior synonym of a 
cycad species, but said by Unwin and Bakhurina to be a feather after 
all, and one that resembles a ratite feather! (It is, clearly, from a 
troodont or therizinosaur:))). Huw is concentrating on the style of 
preservation, the controls on deposition etc., and the taphonomy of 
the fauna.

COTTON, T., O'DEA, A., McCOBB, L. and DYKE, G. (eds) 1999. 
Progressive Palaeontology 1999: Programme and Abstracts. Univ. of 
Bristol (Bristol).

That's that. I'm off to pay for my flight to Denver. Bye bye 
hard-earned cash.

"Come ye out, bird of the shadows"