Re: Thoughts about the arboreal dinosaur

[Ronald Orenstein <ornstn@home.com>]

At 04:29 PM 28/06/2000 -0400, Grant Harding wrote:
> First of all, when I was looking through a bird identification guide the 
> other day, I learned that nightjars and hummingbirds have an elongated 
> middle toe with a curved claw called a "feather-comb", used for grooming.

Technically this is called a pectinated claw, referring to the serrated 
edge; it is best developed in herons, though it is also found in pratincoles.

>   I'm also guessing that aye-ayes probably use their elongated finger 
> partly for combing their fur (in addition to finding and digging out insects).

According to Walker's Mammals of the World (6th ed), an aye-aye will 
occasionally use "its long third finger in combing, scratching, and 
cleansing; the other fingers are flexed during this performance".

> This made me wonder: could the long finger on the new dinosaur indicate 
> the presence of some kind of feathery or dinofuzzy integument? (Assuming 
> that none was preserved, of course; once again, I haven't seen the specimen.)

Considering that the finger may have served more than one purpose, I would 
not call this conclusive - though I have suggested before on this list that 
the presence of feathers pretty much implies that some sort of grooming 
behaviour must have existed, and some fossils might show structures (eg 
combs on claws or teeth) that could be indicators of feathers or 
protofeathers (for example, how about the very fine teeth on some 
pterosaurs like Ctenochasma?).

--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com