Re: Enigmosaur questions

["Mickey Mortimer" <Mickey_Mortimer111@msn.com>]

Jaime Headden wrote-

> <What taxa preserved fused premaxillaries?  I had heard of this as an
> oviraptorosaur or enigmosaur synapomorphy...but apparently it was absent
> in some oviraptorids...>
>
>   Depends. The really only exception is *Citipati*, in which the ventral
> end of the premaxillae is not fused, but the dorsal part is.
> *Conchoraptor*, *Khaan*, *Oviraptor*, GI SPS 100/42, some undescribed
> skulls, and *Erlikosaurus* have fused premaxillae. *Caudipteryx* has been
> posited as a basal oviraptorosaur, and lacks fused premaxillae.

Erlikosaurus lacks fused premaxillae, as explicitly described and
illustrated by Clark et al. (1994).
It's true Caudipteryx lacks fused premaxillae, both species do in fact (Ji
et al., 1998; Zhou et al., 2000).
Protarchaeopteryx is also coded as having unfused premaxillae by Ji et al.
(1998).
The condition in Chirostenotes is still undescribed.
Although Clark et al. (2002) describe Citipati's premaxillae as fused, a
clear suture is visible between the elements on both their ventral and
anterior surfaces.  This is the only oviraptorid skull illustrated/described
well enough to determine the condition in.  However, Osmolska (1976)
illustrated the juvenile crestless skull ZPAL MgD-I/95 with a median suture,
as did Barsbold et al. (1990) for Conchoraptor and ventrally for Citipati
sp. (IGM 100/42).  The condition in Oviraptor philoceratops is certainly
indeterminate.
So I would say no enigmosaurs have fused premaxillae, which is a
synapomorphy of Pygostylia.

> <How long were *Beipiaosaurus*, *Alxasaurus*, *Neimongosaurus*,
> *Nothronychus*, and the other segnosaurs?>

I'm preparing an in-depth examination of this to be posted tonight....

Mickey Mortimer