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.
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 outgroup to Aves if alvarezsaurs are closest). Sure, they also have a ton of bird-like characters, but that's just how the current cladograms crumble.