[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
The Cretaceous Biodiversity conference was held at Portsmouth
University, England, on 10th and 11th July (not 11th and 12th as
advertised). Talks covered several aspects of Cretaceous biodiversity
including coral reefs, forams and insects. Emphasis was on tetrapods
- this was not actually intentional, and was also unfortunate because
tetrapods are not informative with regard to biodiversity as a
whole. What the hey, they are the most interesting animals of them
all :) Here are the highlights (i.e. the tetrapod talks).
Michael BENTON spoke about the diversity of European and African
Cretaceous dinosaurs. The record is patchy but new discoveries in
eastern Europe (e.g. Romania) show that dinosaurs were abundant, but
living at relatively low taxic diversity. Biogeographically
problematic taxa, such as _Pelecanimimus_ and the supposed
pachycephalosaur _Yaverlandia_, show that we do not have anywhere
near the full picture.
Darren NAISH spoke about aspects of diversity seen within Wealden
Paul DAVIS reviewed Mesozoic birds and showed loads of amazing
pictures. Among these were the raquet-tailed _Confuciusornis_ we are
all now familiar with (and, incidentally, the male specimen in the
_National Geographic_ article is not the same as the male specimens
Paul showed.. are they different species?), as well as about three
new genera from the Yixian and Jiufotang Formations. All are unnamed,
and all are very odd little creatures indeed. Because skeletal
reconstructions of _Confuciusornis_ thus far published are not
accurate, Paul produced his own.
By throwing (nearly) all Mesozoic birds into a cladistic analysis,
Paul produced a totally new Mesozoic avian phylogeny, full of
surprises. I can believe it mainly because I have heard of
cases where similar results have been generated by other workers.
Paul is due to publish on it, so I'll keep quiet for now.
Susan EVANS gave overviews of lepidosaur and lissamphibian diversity
in Cretaceous faunas. The fossil record of both groups basically
does not approach extant faunas in terms of number of taxa, and
different community structures are sometimes present: some of this is
because of taphonomic bias, but other factors are also in play such
as the predominantly Tertiary radiation of frogs, and the fact that
high-profile publications are not willing to publish papers on things
like Mesozoic frogs and lizards... for some reason they do not
consider them as interesting as birds or mammals.
In terms of ecotype, lizards are not very diverse in the Jurassic
(all are insectivorous), and in the Early Cretaceous ecotype
diversity is low too. Toward the end of the Cretaceous, they exhibit
far greater size ranges and occupy many different ecological niches.
David UNWIN gave an absolutely excellent talk on Cretaceous pterosaur
diversity. The pterosaur fossil record is very incomplete and lists
of pterosaur diversity charted against time are misleading. Many
bits of the Cretaceous lack pterosaur fossils, or only have little
bitty pieces as representative. Some of the 'best known' pterosaurs,
including _Quetzalcoatlus_ and _Dsungaripterus_, have not been
adequately described, and the current approach of institution
departments and of funding bodies provides a hostile environment for
the construction of detailed monographs.
Suggestions that latest Cretaceous pterosaurs were all
gigantic are not correct, nor are claims that only latest
Cretaceous pterosaurs were gigantic. However, some of the smaller
latest Cretaceous taxa may be juveniles of the gigantic taxa (i.e.
_Quetzalcoatlus_ and _Arambourgiania_, which may be synonymous). What
is notable is that Cretaceous pterosaurs do not exist at sizes
smaller than 1 m wingspan, whereas Triassic and Jurassic pterosaurs
were (virtually without exception) within this size range. A new
generic name for _Phobetor_ was used: this name is actually
preoccupied by a fish.
On Saturday 11th we embarked on a field trip to Cretaceous localities
on the Isle of Wight. The weather made it hell, but at Sandown Museum
bits of the new theropod were displayed. I found a dead cormorant
which is currently decomposing in a hole in the ground somewhere in
the university grounds.
"Seems to me that you seem to be confused"