Re: Fate of Protoarchaeopteryx(Pygostyle origins?)

[Luis Rey <luisrey@ndirect.co.uk>]

This is the first time (apart from a brief mention in my summary of the latest
SVP in Mexico that I posted a while ago) that I see this brilliant paper
mentioned in this list.
The three of them were presenting a poster with the same title that included
remarkable bird embryo photographs  compared directly to photographs of
dinosaur specimens. The similarities were so remarkable (the embryonic leg of a
chicken is virtually indistinguishable from a T.rex, size differences apart)
and the  pictures (that  admittedly were quite difficult to take) were so well
done, that I took Jacques Gauthier to meet them... a meeting that started as a
amicable chat and soon developed in a more-than-an- hour exchange in situ. If
Gauthier was so impressed that says it all.
Highly recommended.

David Marjanovic wrote::

>
> David Rubilar, Alexander Vergas & David Lemus: The dinosaur-bird transition
> compared to the development of the chick (*Gallus gallus*). JVP 20(3)
> September 2000 Abstracts 65Af.
>
> "Chick and lizard (*Liolaemus gravenhorsti*) embryos were cleared and
> stained [...] for examination of skeleton development. *L. gravenhorsti* was
> included for comparison to a non dinosaur-descended sauropsid. Striking
> resemblances to non-avian dinosaurs and to changes in the transition from
> dinosaurs to birds were found in the development of the chick. Dinosaur
> features in the chick absent in the lizard are[: ?] a small sized first
> pedal digit in a high position, at about mid-height of the metatarsi of the
> remaining digits and apparently oriented in the same direction as these;
> posterior inclination of infraprezygapophyseal laminae in the neck as in
> large tetanuran theropods; inward torsion of the innermost finger (I) before
> fusion of digits II and III; furcula with a wide angle (v-shaped), conic
> 'protopygostile' [sic] of 4-5 vertebrae with anterior inclination of neural
> arches (as in oviraptorids). Changes in limb proportions occur as in the
> evolution from dinosaurs to birds, such as lengthening of the scapula and of
> the hand; forelimb proportions at 6-7 days are strikingly similar to large
> Tetanurae theropods such as Allosauridae and at day 9-10 to Maniraptora.
> Reduction and fusion of elements in birds is seen to occur after a basically
> dinosaurian configuration is established (e. g. fibula is as long as tibia,
> tarsi and metatarsi are unfused). Long feathers first appear on the hand and
> forearm and on the pygostyle as in *Caudipteryx zoui*."
>
> **********************************
> "We deeply care about the environment."
>
> US President George W. Bush, just on TV

--
Luis Rey

Visit my website on http://www.ndirect.co.uk/~luisrey