Re: Dinofarts / Sauropod methane emissions

[Mike Keesey <keesey@gmail.com>]

On Tue, May 8, 2012 at 10:48 AM, Erik Boehm <erikboehm07@yahoo.com> wrote:
>
> An analogy: Occasionally mules, hybrids of Horses and Donkeys, are fertile.
> If one were to establish a breeding population of mules (lets assume it 
> happened, its not out of the realm of possibility) - would you group mules in 
> the Horse clade, or the Donkey clade?

Both. Unlike taxa of the same rank, clades are allowed to overlap. For
example, see PhyloCode Note 2.1.3:
http://www.ohio.edu/phylocode/art1-3.html#note2.1.3

In fact, our own species is the result of several overlapping clades:
http://3lbmonkeybrain.blogspot.com/2011/10/human-clades.html

> Could you define either clade without including mules, and still have it be 
> monophyletic?

Nope. A clade (=monophyletic taxon) includes an ancestor and *all*
descendants, by definition.

So, for example, eukaryotes are (probably) both within Neomura (along
with Archaea) and Rickettsiales (a subclade of Alphaprotoebacteria).

-- 
T. Michael Keesey
http://tmkeesey.net/