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Re: The Papers That Ate Cincinnati



On 5/6/07, Tim Williams <twilliams_alpha@hotmail.com> wrote:

>Presumably the panclade name would be _Pan-Opisthocomus_ or >pan-Opisthocomus or something along those lines. It would be >permissible, e.g., to define _Opisthocomus_ as "_Opisthocomus hoazin_ and >all of its descendants".

Wouldn't this be a tautology?

Only if _O. hoazin_ goes extinct before giving rise to other species....

>Alternately, you could use _Opisthocomiformes_ for the total group.

Yep, this is my favourite option.  Trouble is, like I said, as well as
having _Opisthocomus hoazin_ as the internal specifier, you would have an
extremely long list of external specifiers.  You would probably need a
representative of almost every other extant neognath 'order' as an external
specifier, to cater for any and all topologies of modern bird phylogeny.

Not true: "Let C be the clade consisting of _Opisthocomus hoazin_ and all descendants thereof. _Opisthocomiformes_ is defined as the first ancestor of _O. hoazin_ (and hence of C) which is not also ancestral to any extant organism outside of C, and all of that first ancestor's descendants."

--
Mike Keesey