From: "Ken Kinman" <kinman@hotmail.com>
To: j_mallon@hotmail.com
Subject: Class AVES expanded (and defined?)
Date: Fri, 25 Jan 2002 03:59:34
Hi Jordan,
My messages aren't getting posted to DML today for some reason.
Anyway, below are some of my responses to yesterday's feedback, plus my
proposal for a primary synapomorphy for Aves sensu lato.
------ Cheers, Ken
****************************************
Initial reactions to my proposal were not too surprising. But
apparently I did not make it clear enough that I am *not* basing this
expanded Aves on vaned feathers, ornithoid eggs, the pelvic structure, etc.
I have already eliminated those for the very reasons that are being
expressed. But they did arise soon after, at nodes not too far within the
new proposed major node.
That is why my new AVES will be based on characters of the forelimbs,
especially in the wrist and manus. One of these is what Mickey Mortimer
(in his post last night) called "true semilunates". The question in my
mind is how does one precisely define "true semilunates", and would this be
the best synapomorphy to choose. SEE NOTE BELOW.
I should note that another benefit of this move will be to bring into
sharper focus the central issues that divide the BANDD group from the BADD
group. This would be a great opportunity to put the BANDD (Birds are not
dinosaur descendants) group on the hotseat and resolve things once and for
all. I would encourage others to participate in such an exercise, but I
plan to pursue it whether anyone else does or not.
Anyway, I chose DML as the most appropriate forum to introduce my
proposal. If there is no interest in it here, I will just have to pursue
it elsewhere. I would hope there would be interest here, but will not
continue it here if no interest is shown. We shall see.
------ Ken Kinman
NOTE: Is the following synapomorphy (for Class AVES sensu lato) precise
enough?:
Possession of a "true" semilunate carpal block, which can be precisely
defined as: A distal carpal structure which (1) is enlarged so as to
fully cap mcI and mcII; (2) has a distinctive semilunate shape; and (3) has
a pronounced trochlear groove on the proximal side.