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Re: Nemicolopterus phylogeny



Quoting "T. Michael Keesey" <keesey@gmail.com>:

On Feb 13, 2008 8:49 AM, david peters <davidrpeters@earthlink.net> wrote:

I'm also one who cannot fathom how toothed spoonbilled pteros are derived from toothless spear-tipped pteros. There's got to be a better cladogram!

CMIIW (I haven't read the paper yet), but couldn't _Nemicolopterus_' toothlessness simply be a convergent character?

[nods head vigorously]

(though I note that David's impression is mistaken; the cladogram given does not suggest that ctenochasmatids are derived from "toothless spear-tipped pteros")

But in the paper (2nd to last paragraph), the authors really do state:

"The phylogenetic position of Nemicolopterus crypticus suggests that the Ornithocheiroidea [including istiodactylids, ornithocheirids, and dsungaripterids] originated from crestless and toothless small insectivorous arboreal forms."

I *think* they were just being sloppy, but they also, bizarrely, say on p. 1985:

"The toothless condition is widespread among the Dsungaripteroidea [Ornithocheiroidea + _Nemi._ + _Nyctosaurus_]."

This is in the section discussing the phylogenetic placement of _Nemi._, and it reads as though it were justification for positing _N._ as a basal dsungaripteroid, which is rubbish unless you accept the proposition that Dsungaripteroidea is plesiomorphically toothless and that at least two sub-clades (Istiodactylidae + Ornithocheiridae and Dsungaripteridae) independently re-evolved teeth from a toothless condition. I'd be loath to say it's *impossible*, but it seems pretty damned unlikely.

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Nicholas J. Pharris
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Max Planck Institute for Evolutionary Anthropology
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