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NEW SVP MARINE REPTILES



The Jaime wrote...

> So quit your "troh-oh-don" pronounciations, folks, as I most
> certainly have heard in the past [but, surprisingly,
> not at SVP, where everyone was talking about
> elephant-nosed ceratop[s]ians and strange four-legged
> _and_ quadrupedal birds!

Now now Jaime, there's nothing wrong with elephant-nosed ceratopians 
or quadrupedal birds:) (but I do have problems with both the hooked 
predentaries of 3 m long centrosaurines and the hooked dentaries of 
indicatorid chicks masquerading as eggteeth:)) Sorry folks: in-jokes 
from SVP. Like Jaime, I think I have a new found affection for 
entelodonts. Not only do they generate dead piles of little cursorial 
camelids and have juveniles with serrated dentition, we now know that 
they drool copiously and have runny noses (but so far as is known, 
they are never ridden by gnomes).

Besides entelodonts and crocodiles that wish they were diadectids, 
one of the things I was most taken with at SVP was the new marine 
reptile research. Bruce Schumacher had a poster on a superb new 
Cenomanian pliosauroid from South Dakota which, he suggests, is 
intermediate between pliosaurids like _Peloneustes_ and polycotylids: 
in other words, it supports pliosauroid monophyly. Funnily enough, 
Arthur Cruickshank is visiting our department today and I hope to 
talk about this with him later. Next to Bruce's poster was Pat 
Druckenmiller's on another pliosauroid (I'm here using that term as a 
morphotype while admitting that it may be a clade), this time from 
the Albian of Montana, and used by Pat as evidence for the paraphyly 
of Pliosauroidea: that is, with polycotylids as closer to 
elasmosaurids and other plesiosauroids than to pliosaurids, a la 
Bakker and Carpenter. One criticism I have of SVP was that the 
posters were not up for long enough, as I never found time to read 
this one. Anyway, it is clear that plesiosaur research is moving 
apace and we are getting some healthy debate.

And it's timely that a new taxon of elasmosaurid, _Occitanosaurus 
tournemirensis_, has just been (re)described in...

Bardet, N., Godefroit, P. and Sciau, J. 1999. A new elasmosaurid 
plesiosaur from the Lower Jurassic of southern France. 
_Palaeontology_ 42: 927-952.

Previously named _Plesiosaurus tournemirensis_ by Sciau, Crochet and 
Mattei (1990) and regarded by Storrs (1997) as referrable to _P. 
guilelmiimperatoris_ (I'm pleased to see people have cleaned up that 
previous trinomial), _Occitanosaurus_ is regarded as a Toarcian 
elasmosaurid with affinities to _Microcleidus_ and _Muraenosaurus_. 
That _Microcleidus_ is now widely regarded as an elasmosaurid is 
admittedly a little surprising, as I only learnt this from Richard 
Forrest in September (SVPCA) following my inspection of a life size 
photo of the type (BMNH 36184) at Dorchester, Dorset. In Bardet et 
al's cladistic analysis, cryptoclidids fall out as the sister-group 
to the elasmosaurids, and advanced Upper K elasmosaurids 
(_Alzadasaurus_, _Thalassomedon_ and _Hydrotherosaurus_) form a 
clade. The Cretaceous taxa _Aristonectes_ and _Morturneria_ are also 
regarded as elasmosaurids, something that was apparently demonstrated 
in Bardet et al. (1991) (that this paper is written in French might 
explain why I had forgotten it:)). 

One final point - Bardet et al. (1999) disagree with Sciau et al's 
(1990) suggestion that lack of nasals in _Occitanosaurus_ is 
diagnostic for the taxon. Sciau et al were incorrect (absence of 
nasals in widespread in plesiosaurs), but Bardet et al's assertion 
that nasals are universally absent in plesiosaurs (in fact, current 
literature - read any of Olivier Rieppel's character lists - regards 
nasals and lacrimals as universally absent in ALL sauropterygians) 
might be incorrrect. Leslie Noe has now presented data on 
ossifications in some pliosaurid skulls (_Liopleurodon_ and 
_Simolestes_) that surely are homologous with nasals and lacrimals. 
Thus at least some plesiosaurs did possess these structures. Leslie 
has yet to publish on this.

In the same issue.....

McGowan, C. and Milner, A. C. 1999. A new Pliensbachian ichthyosaur 
from Dorset, ichthyosaur. _Palaeontology_ 42: 761-768.

The new leptonectid _Leptonectes moorei_ is described from a juvenile 
partial skeleton: short snout, massive eyes. This animal was reported 
in local press in 1995 and we thought it must be a juvenile. Though 
the holotype >is< a juvenile, it is estimated from rostral 
proportions that the adult would still be relatively short-snouted 
compared to some other leptonectids. Thus, as well as going very 
long-snouted during their evolution, some of the eurhinosaurians 
(sensu Motani - who sadly I did *not* get to talk to at SVP) also 
became short snouted. Very interesting from an ecomorphological point 
of view, and reminiscent of similar things that happened in some 
odontocete groups.

It was great to meet you all in Denver, even if the difficulties 
myself and my travelling partner (Stig Walsh) had to endure made much 
of the trip a bit of a nightmare. Being taken to the San Luis Valley 
by Dan Varner (to see the migrating Sandhill cranes) made up for 
much of the pain, as did discovery of the solution to the question 
"Why did maniraptorans evolve those folding forelimbs?" I refer to 
the patented Buckles-Pharris hand shake:) And at least I have caught 
up on the sleep I lost (staying up until 5 am to talk about 
oviraptorosaurian synapomorphies kind of takes it out of you). Ok, so 
it's Buchholz. Troutman where were you??

More to come.

"Have you been using me as your main source of information?"
"No, not my main source - I also make stuff up" - - Dogbert, 1999.

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                               [COMING SOON: 
http://www.naish-zoology.com]