Re: Spinostropheus gautieri identified as an ... alvare.. wait a second!

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

Tim Williams wrote-

> Interestingly, Fig. 2 in Sereno et al. (2004), of a skeletal
reconstruction
> of _S. gautieri_, does not actually show the caudals; cervicals, dorsals
and
> the fragmentary sacrals are shown, as is the proximal humerus.  This
humerus
> fragment must have come from the holotype (or lectotype, I guess it should
> be called).  I would not read too much into this, but it is worth noting.
I
> wouldn't be surprised if Lapparent's original "type" specimen for _E.
> gautieri_ was a chimera.

Nor would I.  I think your "proximal humerus" is the first dorsal rib.

> Also, the most convincing alvarezsaurid characters are in the caudal
> vertebrae...
>
> http://www.cmnh.org/dinoarch/2002Jul/msg00370.html

True, those parts may still be alvarezsaurid.  But I'd really like to know
how the associated skeleton of Lapparent compares to Sereno's specimen and
the Spinostropheus holotype before saying anything for certain.  The sacral
centra of both of Lapparent's specimens are supposed to be similarly broad.
But the associated skeleton's sacrum is apparently only two vertebrae, fused
together.  They are described as being opisthocoelous and having a large
neural canal.  Alvarezsaurids have enlarged dorsal neural canals, and
derived taxa (Patagonykus + Mononykinae) have opisthocoelous dorsals, but
their sacral neural canals are of normal size (~25% of central height) and
their sacrals are procoelous.  No other similarities between the associated
skeleton of Lapparent and holotype are noted in the text, and only the
sacrals of the former are illustrated (the tibia is also supposed to be
illustrated, but the illustrated tibia seems to be from the holotype
instead).

Mickey Mortimer