Re: [dinosaur] Theropod and bird lifestyles from ungual bone curvatures (free pdf)

[Tim Williams <tijawi@gmail.com>]

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

> ...if we're not simply looking at taphonomic distortion.

Good point, and the authors acknowledge this possibility:

"The models occasionally yielded conflicting predictions for left and
right PD-III claws
belonging to a single fossil specimen. This could be caused by natural
variation within the population,
taphonomic distortion, or some unknown factor. The measured fossil claws did not
exhibit any obvious distortion and often plotted within the overlap
between morphospaces,
and so it is plausible slight, naturally-occurring differences between
claw angles could result in
conflicting predictions."

Frankly, irrespective of inter- or intra-specimen variation, I don't
think ungual curvature is producing a reliable signal for the
ecologies of a whole bunch of basal paravians (including
_Archaeopteryx_ and _Microraptor_).