Re: BIRD CHARACTERISITICS

[charger72@juno.com]

I'm not sure what the diagnostic features would be, but to make sure
everyone knows what we are talking about I will list the unique features
of birds. Some of these features are shared by other animals, but they
are distinctly avian characteristics.

1) large sternum with a deep furcula (keel) attached to long ribs and
elongated coracoid bones.
2) shoulder girdle rotated and shifted upward, even with the backbone.
3) elongated lower leg bones and a modified ankle (tarso-metatarsus)
4) elongated ilium attached to at least 11 vertebrae and as many as 23.
5) ischium and pubis point backward to make room for the sternum.
6) short body centered over the feet with breastbone between the knees.
7) shortened pygostyle tail.
8) merged temporal openings.
9) feathers.

Archeopteryx has only the last feature. One should expect to find the
others to some extent (or at least the beginings of them) in ancestral
birds.


On Tue, 21 Oct 1997 11:58:23 -0600 (MDT) Jeffrey Martz
<martz@holly.ColoState.EDU> writes:
>
>
>     To expand a little, what are the diagnostic charcteristics of 
>Aves?
>Again, alternatives not based on the _Archaeopteryx_ &/or theropod
>ancestry theory would also be nice.
>
>LN Jeff 
>O-
>
>