PALAEOCENE HADROSAUR, NEW REFS

[darren.naish@port.ac.uk]

Tracy wrote..
 
> << There is a large hadrosaur femur from New Mexico that is above the
> K/T boundary. It wasn't reworked into the Early Paleocene.>>

Dan Varner responded..

>        How do they know that? DV

In the paper they argue that the pristine bone surface proves that it was 
not transported. 

While I'm here, the following just in...

Ruxton, G. D. 2001. Heat loss from giant extinct reptiles. _Proc. R. 
Soc. Lond. B_ 268, 1921-1924.

Despite the title, this is only tangentially related to dinosaurs or other 
extinct reptiles and is essentially about the physics of convection: large 
bodies lose heat quicker when immersed in water unless the body is in 
fresh water, is still and there are no air or water currents. In that 
situation conduction and convection in air exceeds conduction in 
water, thus heat loss in both media is about the same. There is no 
discussion of how this might be relevant to differing physiological 
strategies.

Modesto, S., Sues. H.-D. & Damiani, R. 2001. A new Triassic 
procolophonoid reptile and its implications for procolophonoid 
survivorship during the Permo-Triassic extinction event. _Proc. R. 
Soc. Lond. B_ 268, 2047-2052.

New taxon _Sauropareion anoplus_ from the Lystrosaurus Zone 
(earliest Triassic) of South Africa. Nice skull with diagnostic caudal 
emargination of the skull deck and unique quadratojugal and 
prearticular characters. Phylogenetic analysis finds it to be the sister-
taxon to the Procolophonidae, thus closer to procolophonids than 
_Coletta_ and the _Barasaurus_-_Owenetta_ clade_. Because 
_Owenetta_ debuts down in the Cistecephalus Zone, _Barasaurus_ 
must have a ghost lineage extending this far. Also interesting is 
mention of an 'in press' paper by Reisz and Scott on a Triassic 
_Owenetta_. Will appear in JVP. Collation of the data means that 
procolophonoids had a 67% survivorship rate through the Permo-Trias 
extinction event, thus parallelling similar low extinction rates in some 
other terrestrial diapsid groups. Modesto et al. note that it's looking 
increasingly likely that small terrestrial vertebrates were little affected 
by the end-Permian event.

Later.

DARREN NAISH 
PALAEOBIOLOGY RESEARCH GROUP
School of Earth & Environmental Sciences
UNIVERSITY OF PORTSMOUTH
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