Re: Thoughts about the arboreal dinosaur

["Grant Harding" <granth@cyberus.ca>]

Sorry about not responding earlier; life tends to get in the way of
important things like checking e-mail. :)

Christian Kammerer wrote:
><<
> That new hatchling dinosaur that Luis Rey mentioned with the aye-aye-like
>finger and opposable hallux sounds fascinating.  >>
>
>Aye-aye like? That sounds a bit much...I've heard sifaka-like,

Sifaka-like?  Cool!  In what way?

>but it would
>have to be one weird, really hyperdeveloped finger to be comparable to the
>thrid digit of Daubentonia.

Fair enough.  The main reason I called it "aye-aye-like" was so people would
know which dinosaur I was talking about.

Also, Patrick Norton wrote:
>>Finally, being arboreal, does it (snip)<
>
>As discussed earlier on this list, there are >no< known osteological
>correlates for arborealty, so using this character to infer an arboreal
>lifestyle is premature.

I wasn't.  I was using the presence of the long, opposable hallux to infer
an arboreal lifestyle.  That's probably premature too, though, I'll admit.

>This elongated digit is a feeding related character
>in lemurs and, as you note, a grooming related character in a couple
species
>of birds.  This means that, so far, extant analogs suggest that this
>character is more likely related to feeding or grooming than the amount of
>time the animal spent in the trees.

Indeed, and see my comment above.

And Ronald Orenstein wrote:
[snip]
>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".

Aha!

[snip]
>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?).

In-ter-es-ting.  Thanks!

-Grant

P.S.  Are sifakas vertical clinger-and-leapers like indris?

--
Grant Harding
High school student/amateur paleontologist
granth@cyberus.ca
Visit Grant Harding's Dinosaur Destination at
http://www.cyberus.ca/~sharding/grant/
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