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Re: Giant birds



Dan Bensen wrote:

<<The holotype of *Gargantuavis* is a partial
pelvis.>>

<Oh! So why do we think it is a (non-dinosaur) bird
and not, say, a big oviraptor? What are the
distinguishing bird fetures one could find on a
pelvis?>

  Hard to tell, because I haven't read the whole
description myself, so I'll be brief. Bird pelvises
and dinosaurian synsacra, in both theropods and
ornithischians, share such features as consecutive
co-ossification of the dorsals or caudals into a
functional unit; in the case of most Aves, it's the
dorsals, rather than the caudals that tend to get
synsacralized. Other features, including a ventral
groove (a sulcus) and elongate ridges parallel to this
groove, are found in several taxa, and again, can be
used diagnostically. But no theropod has the level of
sacralization or fusion as seen in Aves, and the
fusion of all lateral processes to each other is
another feature (in *Gargantuavis* that very, very few
theropods come close to meering, and oviraptorosaurs
and ornithomimosaurs are not among them. Definately
not dromaeosaurs, Archie, or *Rahona*, though while
the latter has a synsacrum, the previous two do not.

  I'll end here. It's a big bird, definately not a
dinosaurs (sensu stricto).


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

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

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