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Re: 11th specimen of Archaeopteryx‏







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Denver Fowler
df9465@yahoo.co.uk
http://www.denverfowler.com
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From: Jaime Headden <qi_leong@hotmail.com>

  I do agree that when I said that the toes grade from two to four, then one, I 
was basing this on back of hand recollection, and am admitting my error. I was 
focusing, at the time, on terrestrial animals and basal paravians, where this 
is true at the base of extinct *Avialae*. Even *Cathayornis yandica* has a 
relatively short first ungual compared to at least unguals 2 and 3, even if 4 
is shorter (I think), and it appears even in *Protopteryx fengningensis*, both 
birds apparently highly arboreal. 

What does "highly arboreal" mean? And based on what?

>  I didn't say anything about Fowler not being cited, although it should be 
>noted that the work in question (Fowler, Freedman & Scannella, 2009) appears 
>to focus on claw _curvature_ and _size_, but not other aspects of morphology. 

Like what? Claw thickness? cross section? there are some descriptions in there 
about that (some of the only descriptions of such things in the bird 
literature, I'll add). Do you know how thick "climbing bird" claws are? not 
very. How does their curvature differ from predatory taxa? reading all the 
Feduccia papers won't help you there because feduccia purposefully excludes 
predatory taxa from his dataset because then nullify his conclusions.

>This may impair its relation to studies on morphology of either the bony claw 
>to the sheath, or other functional implications of curvature. 

Again, we publish data from a set of eagle claws that had removable keratinous 
sheaths. These document the size of the ungual and size of the sheath, showing 
that they are related in this small example (other examples from our osteology 
collection show the same thing). Burnham's recent paper mis-cites us on this, 
and he provides all sorts of unsubstantiated measurements suggesting that 
unguals are not related to claw size, based on (chinese, pr

>That is, the scope of the work is too narrow, even if the data set it draws 
>upon (excluding oddities like swifts or palmate-footed birds) can be used in 
>general.

Hmmm... well, I believe our study was the first to measure all claws on bird 
feet (at the time: there was another study published while we were in prep, 
although it did not measure size, only curvature): all other studies measured 
only one or two digits, usually either I and III, or just III. So, as it 
happens, if you're talking about published studies looking at interdigital claw 
size, then ours is pretty much the only one, regardless of whether or not our 
"scope is too narrow": it's the only published scope there is.

> My cites and quoted comments were based solely on the topic of inference of 
> arboreality from claw geometry (Yalden, Feduccia, et al.) or microstructure 
> and FEA (Manning et al.), which is what this thread is somewhat about. 

Well, then you'll like our new paper. You seem to be mainly citing the 
non-avian dinosaur-related literature on claws. There is other literature out 
there (although admittedly, not all that much). And besides, notions of 
arboreal or non-arboreal physical characters (curvature) of claws are pretty 
meaningless when you purposefully exclude predatory taxa (as Feduccia does), or 
scan hand claws and transfer function to foot claws. I'm also not sure if you 
know what claw geometry work is out there. I haven't seen anyone mention the 
difference between circular curvature, and logarithmic spirals. Studies on 
arboreal mammals and lizards. etc. Just the same old dino-bird papers. Do you 
know the difference between curvature/morphology for predation, and that for 
climbing?