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Re: Interpreting the autopodia of tetrapods - comment
Thanks a lot guys! That paper has been cited fewer than a dozen times
and you're trying to knock it down?
First of all, scientists commonly have SIWOTI syndrome.
Furthermore, often it is surprisingly useful to rigorously demonstrate
what everyone or almost everyone thought they already knew. Consider the
paper on the toilet-lid-like biomechanics of *Gerrothorax* in the JVP
of, I think, December 2008: AFAIK nobody had ever doubted that this kind
of temnospondyls used suction feeding by head-lifting, but it had only
been asserted and never tested; Jenkins et al. tested it, and in the
process produced an impressive and very useful work on the comparative
and functional morphology of *Gerrothorax*. One might have thought
they'd only manage to submit it to a Journal of Negative Results ("we
tried to falsify the toilet-lid hypothesis and failed resoundingly");
instead they got a Featured Article in JVP, with title illustration and all.
Your 2000a paper had the effect of spurring the Mainstream Establishment
to action. That's a good thing, don't you think?
Contra the Hone, Sullivan and Bennett (HSandB) conclusions, the odd
thing about this paper is how often HSandB report that PILs can
indeed be drawn and may have some usefulness. They report:
"IP [interphalangeal] hinge lines can often be superimposed on 2-D
drawings of tetrapod mani or pedes."
Note how they write "2-D drawings"? That's British understatement for
"anything but the real thing"...
However, they're wrong in using "mani". The plural is _manus_, just like
the singular, except for unwritten vowel length.
“Some hinge lines clearly are valid, in the sense that straight lines
can indeed be drawn precisely through three or more joint centres or
ungual tips for some tetrapod digits in some positions.”
"Some [...] in some positions."
Nothing about these lines was ever meant to be as precise as Hone,
Sullivan and Bennett (2009) appear to demand. In fact, some clades
are specified by hinge lines that intersect the middle of certain
phalanges and unguals. That breaks all the so-called “rules,” but
that’s okay, or so I have observed.
Is it really okay? Does it work biomechanically?
First of all, this hypothesis was never meant to be
proven on one-, two- and three-toed taxa. It applies only as a
Did you make that clear in your paper?
Hoping to distance pterosaurs from my digitigrade reconstruction of
Cosesaurus (matched to the digitigrade ichnite Rotodactylus) HSandB
report, "Moreover, the suggestion of a close relationship between
pterosaurs and prolacertiforms such as Cosesaurus is contradicted by
a considerable weight of opposing evidence.” Their evidence consisted
of six cladistic analyses in which Cosesaurus was not included as a
tested taxon and one analysis (Hone and Benton 2008) in which only a
quarter of its characters were scored.
What do you mean by "only a quarter of its characters were scored"? Do
you mean they put question marks for 3 out of every 4 known character
states of *Cosesaurus*?