RE: Umoonasaurus, crested plesiosaur from Australia

["Choo, Brian" <bchoo@museum.vic.gov.au>]

Its about time that "Eric" got a name (wouldn't have realised this was Eric if 
Mike Lee wasn't visiting)... not overly surprised to see he is not a 
Leptocleidus after all.

Brian Choo

Vertebrate palaeontologist and illustrator
website = www.geocities.com/ozraptor4
livejournal = http://www.livejournal.com/users/ozraptor4/


-----Original Message-----
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of Tim 
Williams
Sent: Wednesday, 5 July 2006 11:37 AM
To: dinosaur@usc.edu
Subject: Umoonasaurus, crested plesiosaur from Australia

Apparently plesiosaurs could be crested too..

Benjamin P. Kear, Natalie I. Schroeder, and Michael S.Y. Lee.  An archaic 
crested plesiosaur in opal from the Lower Cretaceous high-latitude deposits 
of Australia.  Proceedings of the Royal Society B:  Biology Letters.  
FirstCite Early Online Publishing.

Abstract: "_Umoonasaurus demoscyllus_ gen. et sp. nov. is a new small-bodied 
(approx. 2.5m) pliosauroid plesiosaur from the Lower Cretaceous 
(Aptian-Albian) of southern Australia. It is represented by several partial 
skeletons (one with a near complete skull is the most complete opalized 
vertebrate fossil yet known), and is unique in having large crests on the 
skull midline and above the orbits. _Umoonasaurus_ is surprisingly archaic 
despite its relatively late age (approx. 115Myr ago) - being simultaneously 
the most basal (primitive) and last surviving rhomaleosaurid. Notably, it 
lacks the 'pliosauromorph' features (large head, short neck, gigantism) 
typically characterizing many more derived Jurassic rhomaleosaurids; thus, 
reinforcing the suspected convergent evolution of the 'pliosauromorph' 
hypercarnivore body plan. _Umoonasaurus_ inhabited an Early Cretaceous 
high-latitude (approx. 70°S) inland seaway subject to seasonally 
near-freezing climatic conditions. This extreme environment supported a 
diverse range of plesiosaur taxa, suggesting that these marine reptiles 
might have possessed adaptations (e.g. heightened metabolic levels) to cope 
with cold-water temperatures. Indeed, survival of ancient endemic lineages 
such as _Umoonasaurus_ is a common phenomenon in Australian Cretaceous 
vertebrate assemblages and might have been facilitated by isolation in 
low-temperature high-latitude regions." 
  
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