[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Alvarezsaur spurs (was Re: dino-lice)



The Aardwolf is a great reference. Interesting.

The thing is that the alvarezsaur forelimbs are highly specialized. In our
minds, a priori, it seems this should correspond to a  highly specialized
ecological niche, right? The aardwolf is not morphologically specialized,
so its more general diet fits this impression.

I can not currently think of an analog species that has highly specialized
limbs that are used for several more general functions, but there may be
one.

And, no matter what alvarezsaurs did, they will be unique in several ways.
Either they'll be the only strictly myrmecophagous cursors or the only
generalists with specialized arms or the only bipedal anteaters, etc. etc.



> On Fri, Apr 29, 2011 at 6:26 PM, Augusto Haro <augustoharo@gmail.com>
> wrote:
>
>> Given that science seems to mostly advance by rejecting hypotheses
>> (according to Popper and his followers at least), perhaps better than
>> saying what alvarezsaurids did is to say what, given evidence, was
>> physically possible for they to do (not trying to lecture anyone! -
>> except perhaps myself). Then we would act by discarding possibilities,
>> and we can find a set of possible behaviours which may well have been
>> accomplished by the animal (even if not all were actually accomplished
>> because of behavioural or phylogenetic constraints). It seems we can
>> discard at least alvarezsaurids did not fly, brachiated like
>> hylobatids or crawled like snakes. :-)  We may then prefer, given
>> physical possibility, the more parsimonious inference given the
>> behavioural repertoire of extant bracketing forms.
>
>
>
> For _Mononykus_, this was the precise purpose of Senter's 2005 study:
>
>
> Senter, P. (2005) Function in the stunted forelimbs of _Mononykus
> olecranus_ (Theropoda), a dinosaurian anteater.  Paleobiology 31:
> 373?381.
>
>
> However, despite the strong biomechanical support for the execution of
> scratch-digging or hook-and-pull movements by the forelimbs, some of
> us (in a somewhat hand-waving fashion) are reluctant to embrace the
> idea that alvarezsaurs were specialized for myrmecophagous habits.
> I'm not dismissing the proposition that _Mononykus_ (and other
> alvarezsaurs) used their stunted forelimbs to tear open insect-nests
> or infested wood; but I have reservations about this being the *only*
> task the forelimbs were used for, or that ants and termites were the
> *only* thing _Mononykus_ ate.  Hence the intuitive attraction of
> alternative (but not mutually exclusive) lifestyles - like feeding on
> carrion, or eggs.
>
>
> The alvarezsaurs might have been most similar to the extant aardwolf
> (_Proteles cristatus_), which feeds predominantly on termites, but
> also feeds on eggs and small prey (other insects and larvae, small
> mammals).  Although the aardwolf is observed hanging around carcasses,
> there are conflicting reports over whether it eats carrion, or is
> merely in search of maggots and carrion beetles.
>
>
>
>
> Cheers
>
> Tim
>
>
>
>
>
> Cheers
>
> Tim
>


Jason Brougham
Senior Principal Preparator
Department of Exhibition
American Museum of Natural History
81st Street at Central Park West
212 496 3544
jaseb@amnh.org