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

Re: Kiwi Wings (was RE: Moasaurus)



"Thomas R. Holtz, Jr." wrote:

> Actually, in kiwis the finger (with ulna) develops on only the medial most
> metacarpal, and indeed only two metacarpals form (not three as in most
> birds).  What is even more remarkable is that kiwi wings develop in two
> alternative fashions: one in which the medial metacarpal is longer and has a
> digit with three phalanges (an ungual and two non-unguals); the other in
> which the medialmost metacarpal is shorter and the digit has only two
> phalanges. (see, for example, Parker, T. J. (1891) Philos. Trans. R. Soc.
> London B 182: 26-134).

If these distinct forms were found in mesozoic theropod skeletons, would
they typically be treated as distinct taxa, and if so, might they be
considered different species, or even different genera?
 
> By comparison with more completely digited birds (and with tetrapod hands in
> general), the first form is producing a morphological metacarpal II with its
> digit, and then a digitless mc III; the other form is producing a
> morphological mc I with its digit, and then a digitless mc II.

Does this have any implications for the BAND argument that birds' three
toes are different from dinosaurs' three toes? 
 
> Ah, the joys of frameshifts and homeoboxes...

If you say so...

Stephen

still trying to work out the implications of the (small) size of the
human genome in terms of phenetic evolution of other species - like
dinosaurs.