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

Some thoughts on AVES




YES, Tim!!!! Actually that's an excellent example (are you shocked that I'm agreeing with you?).
Anchoring Aves on genus Archaeopteryx was an accident of history, and given how small the gap between archaeopterygids and dromaeosaurs has now become, I will probably break with that tradition when the time seems right (most likely when Gregory Paul or George O., or someone else, comes up with a proposal I really like and with which I can heartily concur).
Another (larger) gap should be chosen to mark the arbitrary line between Reptilia and Aves, but this time it should be based on osteological characters that are much more clear-cut (like those which divide therapsids and mammals). Yes, a character-based taxon---do I hear booing in the cladist camp? Sorry, but I think that is the best way to ensure relative stability of content in the long run (it did for mammals before the cladistic splintering messed it all up).
Where that new line should be drawn is still far from clear, so in the meantime we should follow the tradition of anchoring it on Archaeopteryx (which happily coincides with the most commonly accepted cladistic formulation). But I predict that soon Archaeopteryx will once again be on the same side of the line as his kissing cousins, but we want to draw the line at a far more stable place so that it will be a long-lasting change. And I predict this will happen whether or not BCF is validated in some form (although I personally hope that it is).
------Ken
*******************************************
Tim Williams wrote:

I see what you mean. Sort of like putting _Archaeopteryx_ into a separate "Class Aves", and separating it from its kissing cousins in the Dromaeosauridae. Indeed, that wouldn't make any sense.





_________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp