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Chicken feet; (WAS Re: Concavenator corcovatus, a new humped carcharodontosaurid from Las Hoyas)



Something of an aside but... I'm sure people have seen the feet of silky 
chickens before (we used to keep them as pets), which variably have feathers 
instead of scales:

http://www.thecozynest.com/picture%20page/mobf_hen_feet.jpg
http://www.gather.com/viewArticle.action?articleId=281474977158232
http://www.mypetchicken.com/about-chickens/chicken-pictures/Silkie-feet-X41.aspx

Curiously enough, silkies are so called becasue the feathers (mostly) are 
filamentous and silky... perhaps more similar to the basal condition. Further, 
silkies have 5 toes on each foot. I wonder whether or not this is a hox-gene 
issue at play. I don't know much about evo-devo, but could it be that silkies 
were being artificially selected for more basal, vestigial characteristics, and 
this had the added effect of maintaining/failing to suppress development of a 
5th digit (however deformed it appears to be).

 ----------------------------------
Denver Fowler
df9465@yahoo.co.uk
http://www.denverfowler.com
-----------------------------------



----- Original Message ----
From: Zach Armstrong <zach.armstrong64@yahoo.com>
To: david.marjanovic@gmx.at; DML <dinosaur@usc.edu>
Sent: Thu, 9 September, 2010 9:16:24
Subject: Re: Concavenator corcovatus, a new humped carcharodontosaurid from Las 
Hoyas

I should point out that someone on the list (I forget who, my apologies) 
pointed 


out that some birds have feathers that grow in-between the scales on their feet 
and cited this image as support:

http://www.flickr.com/photos/hardworkinghippy/1874087885/

It shows the feet of a dead Barn Owl, and it is quite clear that on the one 
foot 


to the right of the image there are FEATHER-LIKE FILAMENTS GROWING IN-BETWEEN 
THE SCALES (!!)[sorry for the caps, I'm not really yelling, just trying to make 
the point stand out]. This appears to not be unique to this specimen, as a 
brief 


google image search on "barn owl feet" will tell you. So I am not sure why that 
Jura says that feathers (or at least, feather-like filaments) and scales are 
mutually ex
n they cover. It seems that the evidence 
from living birds would suggest otherwise. More importantly, this suggests that 
some small animals that we would expect to have had feathers, but that instead 
only preserve scales (such as Juravenator) may have had (at least) a light 
covering of feather-like filaments anyway.

This also may suggest why larger theropods could, as they grew, lose or reduce 
their fluffy integumentary layer as they grew larger, and be covered 
predominately in scales.

Best,

Zach



----- Original Message ----
From: David Marjanovic <david.marjanovic@gmx.at>
To: DML <dinosaur@usc.edu>
Sent: Thu, September 9, 2010 4:45:44 AM
Subject: Re: Concavenator corcovatus, a new humped carcharodontosaurid from Las 
Hoyas

On 09.09.2010 09:38, Tim Williams wrote:

>  "Jura" <pristichampsus@yahoo.com> wrote:
> 
> > Sad, it really just reads like the authors want these to be quill
> > knobs more than anything else. Maybe the actual paper offers better
> > insight.

Sometimes it reads just like Jura wants these to be anything else more than 
quill knobs. ;-)

Besides, I don't agree the abstract is overly enthusiastic. Quite the opposite. 
To me reads it reads like "they look like quill knobs, walk like quill knobs, 
quack like quill knobs -- surely we've overlooked something???".

>  Hmmm... I really don't see why the idea of quill knobs in a
>  carcharodontosaur is so controversial. We already know that
>  _Velociraptor_ had them. _Velociraptor_ couldn't fly, and there's no
>  compelling evidence that it evolved from flighted ancestors. So
>  _Velociraptor_ tells us that the presence of quill knobs cannot be
>  assumed to indicate flight ability. _Concavenator_ tells us that
>  quill knobs can exist in non-maniraptorans.

*Allosaurus*, and *Concavenator* itself, are known to have scales elsewhere on 
the body, and not just on the feet or lower legs. This is not known to ever 
occur in Neornithes, and Jura maintains that it's outright impossible for some 
development genetics reason that I don't quite r