----- Original Message -----
Sent: Thursday, December 21, 2000 3:46
Subject: Re: Details on
David Marjanovic wrote-
I've just got the Nature paper.
Microraptor has distally placed and long halluces (both more so
than in Archaeopteryx), but they are definitely not reversed. Of
course, I can't judge whether it may have been revers*ible*, and
preservation is another issue...
My statement was based on the coding of this
character in Xu et al.'s data matrix.
Hm... there seem to have happened a few blunders in
this matrix (I just got access to the Supplementary Information). For example,
character 28 (shape of fused clavicles: absent (0), greater than 90° (1), less
than 90° (2) was coded as 0 in Allosaurus. Maybe there is a typo
BTW, what arguments are there to exclude
alvarezsaurids from birds? The prokinetic skull of Shuvuuia seems
clearly avian to me.
They just never fall out as avians (Archaeopteryx
+ Neornithes) in any of my cladograms (or the AMNH team's recent ones,
Sereno's, etc.). Alvarezsaurids have various primitive characteristics
like short coracoids, scapulae without triangular anteriorly projecting
acromions, ventrally directed glenoids and the lack of a proximodorsal
ischial process that combine with the more birdlike characters of some
dromaeosaurs to place them below Aves. At most, sometimes they're the
sister group to Aves, but my most recent phylogenies (with Microraptor added)
place dromaeosaurs above them and troodontids (which are the
[next] outgroup to Aves if alvarezsaurs are closest). Sure,
they also have a ton of bird-like characters, but that's just how the current
The primitive characteristics in the shoulders of
alvarezsaurids could be related to secondary flightlessness (still no-one has a
good idea what their arms were good for?). The scapula and coracoid of
Gastornis (aka Diatryma) look like those of a troodontid, e.
g. Sinornithoides. I can't say anything about that ischial
Both alvarezsaurs and (basal) oviraptorosaurs (and
segnosaurs?) have quite short, flexible tails; if oviraptorosaurs are closely
related to pygostylians... more in my forthcoming article :.-(