Re: Brazilian scientists claim oldest dino findings

["Jaime A. Headden" <qilongia@yahoo.com>]

David Marjanovic (david.marjanovic@gmx.at) wrote:

<Well, erm. The number the dinosaurs started out with is the usual amniote 2.
Are they saying it's a theropod? Or an ornithischian even?>

  The authors are not using the number of sacrals as translated as an apomorphy
for dinosaurs, but as a referent to likely being dinosaurian, which do tend to
increase sacrals, rather than stabilize around 2 as in other Triassic
terrestrial vertebrates of the time.

<To the contrary. They are almost straight. Looks close to the herbivorous
condition.>

  Some of the teeth are VERY curved, convex on the mesial carina, with a
concave distal carina, some more or less hooked in aspect. We might be using
different criteria for curved, however, but note that many strictly carnivorous
animals can have nearly straight teeth on one carina (*Ceratosaurus*,
abelisaurids, tyrannosaurids, etc.) while having a convex mesial carina. This
is even true of some dromaeosaurids (and I'm not talking about
*Dromaeosaurus*).

<Cheetah.>

  Guepard is another name for a cheetah, however. Perhaps a generic term to
refer to any of the spotted African cats. It is, as one might note, a variation
on "leopard" which was likely why David is attempting to correct the blurb.

<BTW, I'm sure Ville is right. The shoulder girdle thing looks like half an
ilium.>

  In the reconstruction, the ischium looks like the scapula, while the
"scapula" looks like the other eroded ilium, including the dorsal thickened
"prong" usually found in such early dinosaurs as *Herrerasaurus*, *Eoraptor*
and even *Guaibasaurus*. The acetabulum likely made the authors think of the
articular glenoid.

  Cheers,

Jaime A. Headden
http://bitestuff.blogspot.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com