Re: Bird reduce their "heating bills" in cold climates

[Dann Pigdon <dannj@alphalink.com.au>]

On Mon, Jul 5th, 2010 at 8:55 AM, David Marjanovic <david.marjanovic@gmx.at> 
wrote:

> >  During the last Friends of Dinosaur Dreaming meeting late last year
> >  it was hinted that Leaellynasaura may have had a hyper- long tail
> >  (the full-scale drawing held up - with the help of several people -
> >  had to be seen to be believed!).
> 
> This was confirmed at the SVP meeting last year. The length is utterly 
> mind-boggling.

Thanks for the tip. I found the abstract from Matthew Herne's talk at the 2009 
SVP meeting. It 
suggests that Leaellynasaura's total body length was three-quarters tail!

--

http://www.vertpaleo.org/meetings/SVPProgramAbstracts09WEB.pdf.pdf

Poster Session III, (Friday)

POSTCRANIAL OSTEOLOGY OF LEAELLYNASAURA AMICAGRAPHICA
(DINOSAURIA; ORNITHISCHIA) FROM THE EARLY CRETACEOUS OF
SOUTHEASTERN AUSTRALIA
HERNE, Matthew, The University of Queensland, Brisabne, Australia

Leaellynasaura amicagraphica, a small bipedal ornithischian dinosaur from the 
Early
Cretaceous (late Aptian-early Albian) of Victoria, Australia, is based on an 
articulated
partial upper jaw and infratemporal region (the holotype). A skull roof 
(including a partial
cranial endocast) and a partial, articulated postcranium have also been 
referred to this taxon,
and have been regarded as belonging to holotype individual. Another partial 
postcranium,
NMV P186047, is also considered to be referrable to L. amigraphica. The taxon 
was
originally assigned to ?Hypsilophodontidae?, but more recently has been 
considered a 
nondryomorphan iguanodontian. Of the postcranium, only isolated referred femora 
and a tibial
pathology have been described.

In this work I describe the osteology of two articulated postcrania referred to 
L.
amicagraphica. Autapomorphies in the haemal arches unite individuals. A 
caudoventrally
expanded postpubic process is shared with Macrogryphosaurus and Camptosaurus, 
and
asymmetrically expanded terminal haemal arches with Macrogryphosaurus, 
Gasparinisaura
and Parksosaurus. Iguanodontian affi nities are further supported by the 
caudoventral
expansion of the ischium and femoral morphology. Pes morphology and the lack of 
ossifi ed
caudal tendons in L. amicagraphica is plesiomorphic at the level of 
Ornithischia. The lack of
a tab-shaped obturator process, extended ischial shaft symphysis and high 
caudal vertebrae
number with protracted vertebral body elongation are shared with basal 
thyreophorans;
thus, past referral of L. amicagraphica postcrania to Ornithopoda may be 
problematic,
and the postcranial material is at best referrable to Genasauria. Caudal 
vertebral count
in L. amicagraphica (>70) is the highest recorded for a non-hadrosaurid 
ornithischian.
Dorsoventral and cranial expansion of postzygapophyses (up to 44% of vertebral 
body
length) on vertebrae in the terminal half of the tail of L. amicagraphica 
suggests an
alternative to ossified tendons to provide caudal axial rigidity. Caudal 
vertebral morphology
suggests a hyper-extended tail of approximately three times estimated 
pre-caudal body
length.

-- 
_____________________________________________________________

Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
_____________________________________________________________