TRIASSIC GIANT SAUROPODS, ORNITHOPSIS

[darren.naish@port.ac.uk]

First off, don't think this has been reported on the list 
before...

Buffetaut, E., Suteethorn, V., Le Loeuff, J., Cuny, G., Tong, 
H. & Khansubha, S. 2002. The first giant dinosaurs: a large 
sauropod from the Late Triassic of Thailand. _C. R. 
Palevol_ 1, 103-109.

I heard about this a while ago but have just got a reprint 
from Sasidhorn (last author in above), currently based here 
at UOP working on _Valdosaurus_. A humerus from the 
Nam Phong Formation is 1040 mm long and thus 
suggestive of a _Camarasaurus_-sized animal 12.6 m or so 
long, or more if different proportions are assumed. They do 
not suggest that the humerus is referable to _Isanosaurus_ 
but this is obviously possible. The paper includes some 
speculations as to why sauropods got so big and they note 
that sauropods attained giant size faster than did other 
dinosaur groups.

Mike Taylor wrote...

> Can anyone explain how the titanosauriform Ornithopsis -- known only
> from a couple of dorsal verts on display at the NHM, London -- came to
> be called "bird face"?

It's actually 'bird likeness' or 'bird appearance' and was 
coined by Seeley (1870) because he thought that the type 
vertebra (the caudal dorsal BMNH 28632) was from a giant 
pterosaur. 

Seeley clearly thought (correctly) that, like birds, pterosaurs 
and sauropods were pneumatic. This may be why Owen 
gave the name _Chondrosteosaurus_ to further Wealden 
sauropod material in 1876. _Chondrosteosaurus_ means 
'cartilage and bone lizard' and reflects Owen's view that 
pleurocoels were occupied by cartilage, not air.

See Naish, D. & Martill, D. M. 2001. Saurischian dinosaurs 
1: Sauropods. In Martill, D. M. & Naish, D. (eds) 
_Dinosaurs of the Isle of Wight_. Pal. Ass. (London), pp. 
185-241.

Also article in press for the sauropod special issue of 
_Quarterly Journal of th Dinosaur Society_.

Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth
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