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RE: 11th specimen of Archaeopteryx‏



Regardless of my previous post pointing out the irony of Denver Fowler refusing 
to use data to contradict my generalized statements, and then making direct 
remarks apparently refuting each of these generalized statements, I feel I 
should still address specific points (although, again, this is still 
generalizing to a degree). My language is specifically (ha!) generalizing, 
because in this case I am NOT drawing on specific points to debate.

1. I have read the relevant literature of at least the work following Yalden 
(1985) and Feduccia (1993) (both of whom claimed the geometry indicated 
arboreal or scansorial adaptations in the unguals of *Archaeopteryx 
lithographica*) up into the last decade on claw recurvature and analyses. I am 
also aware of Fowler's unpublished work, but not of its specifics. Until that's 
published, I could care less what it says. I've been accused by some of being 
naive for ignoring unpublished data when it is presented, but it is only 
scientific to do so: I cannot refute something when that data is not available, 
and it is not "available" until it is published. If it is Fowler's intent to 
publicly refute my arguments, he should do this with data, not anecdotes; 
statements like "you are wrong" without anything to qualify it mean nothing.

2. My comments regarding climbing are generalized, and I have not specified the 
form of climbing. I have not, for example, differentiated a bird "hanging" by 
its claws and/or beak, by birds crawling down/hanging from trunks or branches, 
or climbing up them, regardless of the slope involved, or a bird "clamboring" 
through branches with beak, claws, and wings (or whatever), as in the case of 
juvenile hoatzin. When I wrote "climbing," I was using this in specific regard 
to the Mannion et al. work, which presumed, on the initial test, that the 
animal would be attempting to move up a vertical or slightly inclined slope 
upwards, and as such, the role of the ungual as a "climbing" device, compared 
favorably to _pitons_, is implicit. It is this, and only this, that I talking 
about when climbing, but I am not excluding other behaviors. Similarly, I have 
not in my statements determined the process by which "climbing" occurs when a 
bird is "upright" or "inverted," such that when the few birds that can climb 
_down_ a tree do so, how they actually do it. I have read at least _two_ papers 
on the subject, but I cannot recall them. They tended to emphasize the use of 
the tail in woodpeckers to "hold on" to the tree surface, while the unguals are 
typcially "scansorial."

3. Virtually every single study on the issue of ungual recurvature has 
differentiated not two, but _three_ morphologies of ungual recurvature: 
terrestrial/cursorial unguals, which are relatively straight (the term 
"relatively" is a generalization, not a specific, and thus does not presume a 
precise measure, nor is it meant to); arboreal unguals, which are highly 
recurved; and scansorial unguals, which are moderately recurved. This is, in 
general, a continuum, and has been so plotted by previous studies, although 
Yalden and Feduccia tended to emphasize arboreal as including scansorial within 
its fold.  Birds that clambor up and down trunks tend to have the third 
morphology, birds that typically perch rather than clambor the second, and 
birds that run the first. These are generalizations, and they do not _exclude_ 
specific behavior, nor did I ever say they did. I also do not presume that the 
relative curvature is, in fact, precisely indicative of these behaviors, as 
they mechanical principles governing claw geometry likely enable behaviors 
secondarily.

4. My comments do not differentiate morphologies that reflect on arboreality or 
scansoriality relative to terrestriality when not deal with claws, which are 
more prevalent in non-avian taxa than otherwise, simply by evidence of 
specialized organs or limbs: e.g., "adhesive" structures on gecko toes, 
prehensile digits or tails, etc. My comments were to generalize that certain 
behaviors could not always be simply inferred based on certain features. They 
were meant to displace the argument away from simply arguing the large second 
pedal ungual of dromaeosaurids is implicitly arboreal.

5. My argument also differentiated the tremendous difference in size of the 
second and third or fourth pedal unguals in dromaeosaurids, the lack of this 
distinction in "Archie," and the implications of this. This was done solely by 
saying "look at extant birds, and look at extant 'perchers'," and asking the 
proponents of "dromaeosaurids in trees" to consider total evidence approaches.

Here's a final point, from Dececchi and Larsson (2011, online here: 
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0022292 ), 
which is the most recent treatment of the topic:

"Claw morphology.
Microraptorines and scansoriopterigids do not have pedal claw curvature values 
within the range of extant climbing birds, but are more similar to ground-based 
foragers (e.g. pigeon) [18]. This contradicts previous work on these taxa [15], 
[17], which relied on the claw curvature data from Feduccia [82]. Feduccia's 
dataset is unreliable, in part because “[b]irds with unusual adaptations - such 
as raptors, long-legged marsh birds, long-legged birds (for example, seriamas) 
that roost and nest low in bushes or trees, birds that resemble Archaeopteryx, 
and so forth - were avoided to eliminate as much as possible birds with claws 
adapted for strange habits or perceived to be generally convergent with those 
of Archaeopteryx for whatever reason.” [82] pg. 790. The exclusion of 
morphologically convergent taxa eliminates extant behavioural analogues.

Additionally, predatory bird claw geometry is indistinguishable from that of 
either perchers or climbers [43] and their inclusion would have significantly 
diminished Feduccia's categorization of Archaeopteryx as arboreal. Glen and 
Bennet's [18] data encompasses a broader range of bird 
ecomorphologies/behaviours and limit claw morphometrics to only the dorsal arch 
of the ungual rather than including the variable and rarely preserved ventral 
arch and joint of the toe pad (that were included by Feduccia [82], see [18] 
for a discussion). Recently, Manning and colleagues [83] suggested that 
dromaeosaur claws were capable of climbing based on finite element analysis of 
a Velociraptor manual claw. Besides our reservations of the use of only manual 
unguals, the extant “climbing” species used for comparison was the Eagle Owl 
(Bubo bubo), a raptorial bird which uses its claws for prey capture, not 
climbing [43]. Birn-Jeffery and Rayfield [84] compared pedal claws of 
dromaeosaurs and trunk climbing birds and found no similarities in design or 
function. Manual claws of theropods are rarely used in analyses of locomotor 
function because their primary use is assumed to have been prey capture, and 
resemble the claws of raptorial birds. Highly recurved manual claws are found 
in a number of large bodied, undoubtedly terrestrial theropods, including, but 
not limited to, spinosauroids [85], [86], allosauroids [87]. therizinosaurs 
[88], [89], and oviraptorids [90]."

and later, from the summary:

"Our results find no anatomical evidence for a scansorial behaviour for 
non-avian paravians and Archaeopteryx.
 Instead, these taxa group well with highly cursorial mammals and birds,
 such as dogs and the ostrich, respectively. Non-avian paravians do not 
even share the scansorial morphologies of even the least scansorial of 
mammals, such as the housecat."

[Citations in the text are included below. Yalden, 1985, not cited within but 
further above, included below that.]

15. Xu X., Zhou Z.-h. & Wang X.-l. 2000. The smallest known non-avian theropod 
dinosaur. _Nature_ 408:705–708.
17. Zhang F.-c., Zhou Z.-h., Xu X. & Wang X.-l. 2002. A juvenile coelurosaurian 
theropod from China indicates arboreal habits. _Naturwissenschaften_ 89:394–398.
18. Glen, C. L. & Bennett, M. B. 2007. Foraging modes of Mesozoic birds and 
non-avian theropods. _Current Biology_ 17:R911–R912.
43. Pike, A. V. L. & Maitland, D. P. 2004. Scaling of bird claws. _Journal of 
Zoology_ 262:73–81.
82. Feduccia, A. 1993. Evidence from claw geometry indicating arboreal habits 
of *Archaeopteryx*. _Science_ 259:790–793.
83. Manning, P. L., Margetts, L., Johnson, M. R., Withers, P. J, Sellers, W. 
I., Falkingham, P. L., Mummery, P. M., Barrett, P. M. & Raymont, D. R. 2009. 
Biomechanics of dromaeosaurid dinosaur claws: Application of X-ray 
microtomography, nanoindentation, and finite element analysis. _The Anatomical 
Record_ 292:1397–405.
85. Porfiri, J. D., Santos, D. D. O. S. & Calvo, J. O. 2007. New Information on 
*Megaraptor Namunhuaiguii* (Theropoda: Tetanurae), Patagonia. _Arquivos do 
Museu Nacional, Rio de Janeiro_ 65:545–550.
86. SSereno, P. C., Beck, A. L., Dutheil, D. B., Gado, B., Larsson, H. C. E., 
Lyon, G. H., Marcot, J. D., Rauhut, O. W. M., Sadleir, R. W., Sidor, C. A., 
Varricchio, D. D., Wilson, G. P. & Wilson, J. A. 1998. A long-snouted predatory 
dinosaur from Africa and the evolution of the spinosaurids. _Science_ 
282:1298-1302.
87. Azuma Y. & Currie, P. J. 2000. A new carnosaur (Dinosauria: Theropoda) from 
the Lower Cretaceous of Japan. _Canadian Journal of Earth Sciences_ 
37:1735–1753.
88. Perle A. 1979. Segnosauridae--A new family of Theropoda from the Lower 
Cretaceous of Mongolia (In Russian). _Trudy — Sovmestnaya 
Sovyetsko-Mongol’skaya Palyeontologicheskaya Ekspeditsiya_ 8:45–55.
89. Zanno, L. E. 2006. The pectoral girdle and forelimb of the primitive 
therizinosauroid *Falcarius utahensis* (Theropoda, maniraptora): Analyzing 
evolutionary trends within Therizinosauroidea. _Journal of Vertebrate 
Paleontology_ 26(3):636–650.
90. Clark, J. M., Norell, M. A. & Chiappe, L. M. 1999. An oviraptorid skeleton 
from the Late Cretaceous of Ukhaa Tolgod, Mongolia, preserved in an avianlike 
brooding position over an oviraptorid nest. _American Museum Novitates_ 
3265:1–36.

Yalden, D. W. 1985. Forelimb function in *Archaeopteryx*. pp.91-97 in Hecht, 
Ostrom, Viohl & Wellnhofer (eds.) _The Beginnings of Birds_. (Freunde des 
Jura-Museums, Eichstätt.)

Cheers,

  Jaime A. Headden
  The Bite Stuff (site v2)
  http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave 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 
Backs)


----------------------------------------
> Date: Mon, 7 Nov 2011 22:02:41 +0000
> From: df9465@yahoo.co.uk
> To: dinosaur@usc.edu
> Subject: Re: 11th specimen of Archaeopteryx‏
>
> _______________________________
> From: Jaime Headden <qi_leong@hotmail.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 
> wrong)
>
>
> >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_ 
> excluded.
>
>
>
> Paper is nearly here (hopefully b4 xmas). That should give you the time to go 
> back and read some papers on claw morphology. You need to.
>
>
> D.
>
> PS. I wrote Fowler et al. 2009. It has lots of claw data in it. Your email 
> didn't.
>
>
> ----------------------------------
> Denver Fowler
> df9465@yahoo.co.uk
> http://www.denverfowler.com
> -----------------------------------