Re: Jumpin' dinos

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

Matt Bonnan wrote:

<In the message, I mentioned the fact that no
dinosaurs or guys like Marasuchus have a calcaneal
(heel) tuber. In jumping animals (kangaroos, for ex.),
the calcaneal tuber is huge and allows the
gastrocnemius to insert on a nice lever arm along with
the plantaris and soleus muscles in the form of the
Achilles tendon.>

  This is essentially untrue, as a look through Sereno
and Arrucci (1994) (JVP 14 (1): 53-73) will show; the
tuber is not extraordinarily developed, as in "proper"
mammals and crocodiles and the like, and while it is
true that pterosaurs and dinosaurs lack the tuber,
*Marasuchus* (PVL 3871) does have a small one, it is
set to the lateral corner of the heel, but is there
nonetheless, roughly 1/3 of an arc and rounded. In
addition, the lagosuchid also possesses a
semi-spherical femoral head.


=====
Jaime "James" A. Headden

"Come the path that leads us to our fortune."

Qilong---is temporarily out of service.
Check back soon.
__________________________________________________
Do You Yahoo!?
Bid and sell for free at http://auctions.yahoo.com