[Taxacom] Paraphyletic tagging
stephen_thorpe at yahoo.co.nz
Fri Oct 3 16:46:58 CDT 2014
Yes, but that opens up another can of worms! If the fossil record was complete, who knows what we would find? Possibly only gradual transitions as even major clades evolved, so mammal/non-mammal, for example, would be an entirely arbitrary distinction.
On Sat, 4/10/14, Curtis Clark <lists at curtisclark.org> wrote:
Subject: Re: [Taxacom] Paraphyletic tagging
To: "taxacom at mailman.nhm.ku.edu" <taxacom at mailman.nhm.ku.edu>
Received: Saturday, 4 October, 2014, 7:39 AM
To be clear, although
Stephen's answer works for the extant species, Ken
guessed that I meant more globally.
On 2014-10-03 7:22 AM, Kenneth
I would rather phrase it: "Amniotes lacking the
> of Mammalia and
created a taxon based on a lack?
> Hair and feathers would not be the best
synapomorphies to pick as they
too gradually (even baby Tyrannosaurus rex may have had
And there are even hairy things in some
Ornithischia that have been
being homologous with feathers. I'm not saying that
thecodonts had feathers, but if a thecodont
fossil with clear feathers
I wouldn't be astounded.
> For Mammalia, the best synapomorphy so far
discovered seems to be when
> the three
ear bones decoupled from the mandible.
But unless that happened in a single speciation
event, there is still
the issue of where in
a gradual shift do we draw the line.
Curtis Clark http://www.csupomona.edu/~jcclark
+1 909 869 4140
Pomona, Pomona CA 91768
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