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Re: 11th specimen of Archaeopteryx
I have followed this thread with interest, as I have papers on the subject
published and pending (waiting on seeing the reviews for the MS based on my
Bristol 2009 talk; so I won't elaborate here due to embargo etc).
The generalized statements weren't even right generally. They aren't based on
any published study, or even any casual observance of bird feet/claws, even a
google image search can show that you are wrong.
Discussion on claw size distributions in birds is published in Fowler et al.
(2009; and references therein). Climbing birds (woodpeckers e.g.) have a
zygodactyl foot, with 2 forward and 2 backward facing toes. One toe of each
pair is typically large, the other small, with the forward facing toes larger
than the backward pair. The foot has this symmetry related to how the
woodpeckers move up and down trunks, sometimes upside down (although usually
the right way up, hence the anterior facing toes are larger). Perching feet and
climbing feet are very different. perching feet (assuming they are adapted
specifically for perching) are anisodactyl (3:1) not zygodactyl (2:2). Claw
size distribution varies strongly depending on what feet are doing. D-I is
usually largest in non-cursors. Non-carnivorous birds usually have a D-III that
is largest of the forward facing toes, followed by D-II, then D-IV. Carnivorous
birds have a D-II that is as large, slightly
larger, or much larger than D-III; D-IV is smallest. Active predators usually
have claws that are more curved than non-predaceous carnivores (although see
fowler et al on owls). There are all sorts of exceptions etc, depending on
specific behaviours. how this all ties into paravian evolution is the subject
of our upcoming paper (PLoS One; reviews completed; literally waiting on
response any day now).
My point: there's often a lot of discussion and "facts" thrown about on this
list. You always seem very quick to provide critiques of others work here and
on your blog, without writing any papers of your own, or (as noted here)
sometimes not having read the relevant literature on what you are discussing.
This list isn't a peer-reviewed journal, I understand that, but it is a very
public outlet for discussion of research, so when I see a string of
"generalized statements" that are almost all very wrong, I think there is a
responsibility to point this out.
From: Jaime Headden <firstname.lastname@example.org>
To: Denver Fowler <email@example.com>; Dinosaur Mailing List <firstname.lastname@example.org>
Sent: Tuesday, 8 November 2011, 10:17
Subject: RE: 11th specimen of Archaeopteryx
I appreciate the absolutely informative and instructive email Denver Fowler
replied with to my generalized statments regarding claw morphology and extant
versus nonextant paravian theropods. The citations provided within by Fowler in
refuting my statement, rather than labelling statements "you are wrong," while
at the same time requiring me to provide statements to back up mine is the
epitome of providing accurate and complete disclosure when making such
generalized statements. I thank Fowler for his ultimately instructive reply to
Jaime A. Headden
The Bite Stuff (site v2)
"Innocent, unbiased observation is a myth." --- P.B. Medawa
ave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion
> Date: Mon, 7 Nov 2011 22:02:41 +0000
> From: email@example.com
> To: firstname.lastname@example.org
> Subject: Re: 11th specimen of Archaeopteryx
> From: Jaime Headden <email@example.com>
> > This is not entirely consistent with arboreality, although that is
> > possible, because climbing birds do not use just one ungual for climbing...
> Yes, I agree.. oh hang on (!):
> >..., they use all forward-projecting unguals,
> Do they? Which climbing birds? What do climbing bird feet look like? Are they
> different from perching bird feet? do you have a citation that explains this?
> (hint, you are wrong).
> > In birds, while the unguals are graded largest to smallest moving from toe
> > two through toe four, then toe one,
> Are they? which birds? do you have a citation that shows this? (hint, you are
> >the unguals even in raptorial birds are relatively similar in size
> Are they? which raptors? do you have a citation which shows this? (hint: you
> are wrong)
> >(cassowaries are freaks with straight pdII-3u's, ignore them)
> Correct. The only thing you got right so far.
> >; in dromaeosaurids, the pdII-3u is often twice the length of any other
> >ungual, a suspiciously bizarre distinction that enforces a functional
> >difference, especially in the strong curvature relative to the other
> >unguals. And recall, despite the huge!
> pdII-3u, the other pedal unguals are _terrestrially_ adapted, even in
> *Archaeopteryx lithographica*. Moreover, it is questionable how one arrives
> at a conclusion that the highly recurved, huge forward ungual is indicative
> of "perching" or arboreality to begin with, merely that climbing is _not_
> Paper is nearly here (hopefully b4 xmas). T
e to go back and read some papers on claw morphology. You need to.
> PS. I wrote Fowler et al. 2009. It has lots of claw data in it. Your email
> Denver Fowler