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Re: Pteromimus and pterosaur origins

Quoting David Marjanovic <david.marjanovic@gmx.at>:

For instance, note that all of the sister and predecessor taxa of pterosaurs in Atanassov's phylogeny have a vestigial or absent pedal digit V. Pterosaurs don't. That's a red flag that should tell any reasonable person, evolution doesn't work that way

Wait, wait, wait, wait, wait. Be very careful with this kind of assumptions. Natural selection is not constrained by history; if a population with a reduced 5th toe that only consists of 2 phalanges anymore finds itself under selective pressure for elongation of that toe, that's what's going to happen. Even lost phalanges can come back; how many phalanges a digit contains depends on the way it grows in the embryo -- a metapodial and its phalanges start as a cartilaginous rod that grows from proximal to distal and segments as it grows --, and, according to an SVP presentation I saw last year, the basal anomodont *Suminia* did reverse from 2-3-3-3-3 to 2-3-4-5-3.

You guys would know better than I, but last I looked, pedal digit V in basal pterosaurs may be long, but it still only consists of two phalanges. That certainly suggests to me that it's been re-elongated secondarily.

Nicholas J. Pharris