Re: Stem-modified node shorthand?

["T. Michael Keesey" <mightyodinn@yahoo.com>]

--- SeanSt8579@aol.com wrote:
> In a message dated 4/14/04 12:01:21 AM Eastern Daylight Time, 
> mightyodinn@yahoo.com writes:
> 
> << Clade(extant Clade(X <- Y)), or {extant {X > Y}}? >>
> 
> I was thinking about something like that, but the problem is, how do you 
> easily denote a hypothetical common ancestor? Like de Queiroz & Gauthier's 
> Neoaves: the most recent common ancestor of Passer and all

Missing a very important word here ("extant"). Without it, this is just a
stem-based definition.

> forms closer to that ancestor than to Galloanserae.

Fortunately they provide species anchors for the node-based _Galloanserae_
(_Gallus gallus_ and _Anser anser_). (Also worthy of note is that they specify
that the clade's anchors are all neognaths; not sure if that fact is worthy of
shorthand recognition or not.)

> "Common ancestor" is down with the plus, "closer to" 
> we got, and "Passer" and "Galloanserae" are easy enough, but how do we 
> symbolize "that ancestor" without having to type it out?

I would say that simply saying "extant" implies a list, and a list would imply
a node-based definition. So, "Clade(extant Clade(_Passer domesticus_ <- _Gallus
gallus_, _Anser anser_)" could translate to "the clade stemming from the last
common ancestor of all extant members of the clade stemming from the first
ancestor of _Passer domesticus_ which is not also ancestral to _Gallus gallus_
or _Anser anser_".

=====
=====> T. Michael Keesey <http://dino.lm.com/contact>
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