Re: paraphyletic Dromaeosauridae (Variraptor)

["Mickey_Mortimer11" <Mickey_Mortimer11@email.msn.com>]

Ken Kinman wrote-

>       Decided that perhaps Variraptor (and Pyroraptor?) might belong with
> the "utahraptorines", or maybe even slightly more primitive (as show
below).
>       Coded the main dromaeosaurids (sensu stricto) together in one clade
> (clade 3A-3B), although my intuition is that dromaeosaurines are more
> primitive than velociraptorines (as I coded it earlier).

I mention that Variraptor has two pairs of cervicodorsal pleurocoels and
look what happens :-) .  Variraptor would be hard to compare to
"utahraptorines", depending completely on comparing the anterior and
posterior dorsal vertebrae to Achillobator.  Once the new material of
Utahraptor is described, we could compare the cervicals, dorsals and sacrals
to Variraptor.  Comparing just the distributio of double pleurocoels reveals
some differences- Utahraptor has single pleurocoels in the cervicals, double
in anterior dorsals and none in posterior dorsals.  Achillobator has single
pleurocoels in cervicals and anterior dorsals, but double in posterior
dorsals.  Variraptor has double in anterior dorsals and single in posterior
dorsals.  Variraptor doesn't show much similarity to "utahraptorines",
instead being more like velociraptorines- posterior serrations much larger
than anterior serrations; elongate pedal phalanx II-2.

Jaime Headden wrote-

> One of the interesting things about *Variraptor* is that the
> cervicodorsals are highly reminiscent of those of *Achillobator* (and
> apparently *Utahraptor*), and as Mickey pointed out, they also resemble
> the cervicodorsals of segnosaurs and oviraptorosaurs and *Avimimus*,
> indicating the form of the vertebrae are plesiomorphic. The form of the
> bones are not found in *Velociraptor*, *Deinonychus*, or the fluffy IVPP
> specimen fluttering around on the http://www.AMNH.org website, and as such
> it is not a stretch to consider the form to be plesiomorphic within
> Maniraptora.

What characters besides the presence of double pleurocoels on various parts
of the vertebral column do you see that are similar in Variraptor,
"utahraptorines", enigmosaurs and Avimimus that aren't seen in
dromaeosaurids?  I would question the ability to get much vertebral data out
of NGMC 91 (not an IVPP specimen) from the photos published so far.
I would concur Dromaeosaurus looks to be very derived though.

Steve Brusatte wrote-

> Be careful.  There is nothing to suggest that _Variraptor_ is even still
valid.  Allain and
> Taquet (2000) (maybe HP Allain will enlighten us further) sunk this genus
as a nomen
> dubium in their paper on the French dromaeosaurid _Pyroraptor_.  IIRC,
they pointed
> out that the holotype of _Variraptor_ possessed no truly diagnostic
features, and that the > majority of the original _Variraptor_ diagnosis was
based on a vertebra found quite some > ways from the type specimen (and at
one point referred to, in a previous paper, as
> Dromaeosauridae indet.)
> _Pyroraptor_, on the other hand, is much stronger taxonomically speaking.
It has been
> suggested that the _Variraptor_ material may represent a _Pyroraptor_
individual,
> although this likely won't be able to be determined due to the poor
quality of the material.

It's true that the authors never listed valid apomorphies for the holotype
of Variraptor, but that doesn't mean they don't exist.  The holotype
posterior dorsal is distinguishable from Deinonychus for instance (shorter
centrum, smaller pleurocoels, neural canal tall), and is presumedly also
differentiable from other eumaniraptorans it can be compared to
(Achillobator, Velociraptor, Saurornitholestes, Unenlagia, Rahonavis, etc.),
though I don't have the time to do so currently.  Pyroraptor also seems
valid, though for less reasons than the diagnosis would have you believe
(deep depression on proximolateral surface of ulna; ventrally concave
metatarsal II).  The two genera could always be synonymous though.

Mickey Mortimer