Re: Protoavis and Megalancosaurus - and the ABSRD model of bird origins

["David Marjanovic" <David.Marjanovic@gmx.at>]

> I call Feduccia's "theory" on bird
> origins "Anything But a Small Running Dinosaur" (ABSRD for short).

*LOL* Perfect!!! :-D

I hope we won't be accused of insulting people... BAND ["Birds Are NOT
Dinosaurs"], BAND leader [Storrs Olson], BANDit [Feduccia, Olson and their
disciples], ABSRD... hmm...

> As the ABSRD theory (it sure ain't a hypothesis)

Why? If I correctly remember the relevant page in www.dinosauria.com/jdp, it
is a hypothesis... (Whatever, nobody seems to care. ;-) )

> supports a Triassic origin
> for the Aves, the presence of a fairly advanced bird in the Norian
> (Chatterjee regards _Protoavis_ as a bird more derived than
_Archaeopteryx)
> is congruent with ABSRD.

In the 1996 version of his book at least, Feduccia mentions *Protoavis*, but
when he writes down the ABSRD scenario, he puts the parachuting stage in the
LT and EJ and the gliding stage in the EJ and MJ. *Protoavis* is, if
anything, a flapper with flight abilities somewhere between Archie and
Confuciusornithidae.

> This relegates _Archaeopteryx_ to a primitive
> relict taxon for its Late Jurassic (Tithonian) time.

So do the MJ and EJ dromaeosaur teeth, if they are correctly identified
(Disclaimer: I haven't seen any of these teeth or illustrations or
descriptions, so for now I can't doubt these identifications), and the MJ
and LJ troodontid teeth, and the LJ ornithomimosaur remains, and probably
*Stokesosaurus* and maybe *Iliosuchus*, and the LJ oviraptorosaur remains,
and maybe the EJ ?segnosaur dentary...

> Chatterjee, however,
> supports the origin of birds from theropods; Feduccia does not.

True. (Feduccia never mentions that Chatterjee does not believe in ABSRD...)

> The cervical vertebrae are also strikingly similar between _Protoavis_ and
> _Megalancosaurus_ [...]
>
> Might (as many have suspected) _Protoavis_ be a chimera?  If so, the type
> material may include at least some drepanosaurid material.

The whole animal, however, is definitely not a drepanosaurid. (The
heterocoelous cervicals are suspect anyway, because they only appear in
fairly derived birds...)

> The Prolacertiformes (= Protorosauria - could someone set
> me straight if these two groups aren't the same)

Me too, please...

> By the way, this paper (Feduccia and Wild, 1993) is
> the first example I've ever seen of morphologically disparate genera being
> linked not by common ancestry, but by an alleged common descendent
(birds).

:-D

> As pointed out by Renesto (2000), the skull and neck of _Megalancosaurus_
do
> show bird-like features (skull triangular in profile, inflated posterior
> region of braincase, hypapophyses on the underside of cervical vertebrae).
> But the postcranium is distinctly un-bird-like, and more like that of a
> modern chameleon.  The paper also gives a purpose for the hypapophyses on
> the underside of the cervicals

The hypapophyses are quite pronounced in *Protoavis*. More tomorrow or so...

> (I'm sure many on this list knew what they're
> for, but I didn't): "The hypapophyses . allowed the insertion of a well
> developed longus colli, for the extension of the neck."  In addition to
the
> tall neural spines of the anterior dorsal vertebrae, for attachment of a
> strong musculature, ".these features permitted the neck of
_Megalancosaurus_
> to be both retracted and suddenly projected forward, as in some projectile
> feeders."
> Or small carnivores - darting the jaws forward to sieze small
> prey.

Same interpretation for *Protoavis*.

> Hypapophyses on the neck vertebrae are also seen in crocodilians,
> varanids (monitors) and coelurosaurian theropods.

Oho!

> Silvio, R. (2000).  Bird-like head on a chameleon body: New specimens of
the
> enigmatic diapsid reptile Megalancosaurus from the Late Triassic of
Northern
> Italy.  Rivista Italiana di Paleontologia e Stratigrafia. 106 (2):
157-180.

Yet another paper I have to look for... (Why are there so many journals?)

BTW, given BCF, BADD and ABSRD, perhaps I should call the hypotheses
proposed by people like Ebel and me WORSE or WORST, for something like
"Watery Origins for Real Still Existing [dinosaurs]" or "Watery Origins for
Real SuperTerrestrials [how poetic :-] ]"...
        Better ideas are welcome, I haven't produced much good poetry so
far...