SVPCA 50, REPORT II

[darren.naish@port.ac.uk]

I doubt if I'll be able to get through all the rest of the 
presentations today but, anyway, here are some more...

CROCODYLOMORPHS

Inken Mueller-Towe compared the Holzmaden 
crocodyliforms _Platysuchus multiscrobiculatus_ (named 
by Wetsphal in 1962) with _Steneosaurus bollensis_ and 
showed that they do differ in various ways. The 
premaxillae, nasals, coracoids and limbs of the two differ in 
shape and proportions but they exhibit some characters 
(lacrimal-postorbital contact) not seen in other teleosaurids. 
_Platysuchus_ may have been a less aquatic animal than 
_Steneosaurus_.

David Allen showed that _Terrestrisuchus_ really should be 
regarded as just a juvenile of _Saltoposuchus_ as all of its 
'distinctive' features (lack of squamosal ridge, no rostral 
dentrart swelling etc) are juvenile features, plus it exhibits 
open neurocentral sutures in the caudals! A plot of the 
hindlimb proportions shows that all the _Terrestrisuchus_ 
and _Saltoposuchus_ specimens can be seen as part of a 
growth series. Incidentally this is all at odds with Clark and 
Sues (2002) who regard these two taxa as distinct and even 
in different sphenosuchian clades. David also tested 
sphenosuchian phylogeny and found the group to be 
paraphyletic. From what I could write down, 
_Sphenosuchus_ and _Dibothrosuchus_ grouped with 
Crocodyliformes while _Saltoposuchus_ did not.

PTEROSAURS

Sarah Sangster re-examined hindlimb morphology in 
_Dimorphodon_. She concluded that the plantigrade pes, 
anterior CoG and other features made a bipedal posture 
impossible.

David Unwin provided a thorough analysis of pterosaur 
hindlimb morphometrics and locomotor modules. A la 
Gatesy and Middleton, pterosaurs (from all groups) were 
plotted onto ternary diagrams and found to occupy a rather 
small morphospace which overlapped that of both bats and 
birds (interestingly, the bird and bat clouds did _not_ 
overlap). Bats occupy about 50% of the morphospace that 
birds do, and pterosaurs occupied a small space than bats. 
Forms for which the wing membrane is known were 
scattered throughout the cloud demonstrating that extensive 
patagia are not an unusual feature of one pterosaur 
subgroup. 

Michael Fastnacht reported an amazing 3-D, articulated 
pterosaur specimen from the Langenberg locality at Oker, 
near Hanover. It includes a complete pelvis, femora and 
vertebral column and differs from all described taxa. The 
femora are most like those of _Dsungaripterus weii_ and the 
very thick-walled tibia also resembles those of that taxon. It 
thus appears to be a true dsungaripterid and thus maybe the 
first from Europe (though some scrappy Romanian material 
might represent this group). The thick tibial walls are 
obviously unusual for an otherwise thin-boned group - 
could it be a strengthening adaptation for forms that have to 
resist impact when landing on the ground?

Have run out of time, and just when all non-dinosaurs are 
out of the way. Am not able to get onto email until next 
week so be patient (unless someone else beats me to it).

-- 
Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL

email: darren.naish@port.ac.uk
tel: 023 92846045