Re: DEFINE BIRD

["Jonathan R. Wagner" <znc14@TTACS.TTU.EDU>]

T. Mike Keesey wrote:
>Official cladistic definition: the most recent ancestor of _Archaeopteryx_
>and modern birds and all of that ancestor's descendants.
[...]
>There was another definition: the most exclusive clade containing all
>modern-day birds.
        With all due respect to Mike and his excellent knowledge of things
dinosaurian, these statements are in error.
        1) By the criteria of Padian and May (1993), the second definition
has priority, now matter how much anyone (or everyone?) agrees with Chiappe
et omnia that the first is somehow "better".
        2) Gauthier (1986) defines Aves as follows:
        Aves (Linneaus, def. Gauthier) = {+ Tinamoui, + Ratitae, +Neognathae}
        Which, as you'll notice, is a crown clade by application only, and
not by definition (as you presented it above).

>That one didn't catch on -- that clade is better termed Neornithes.
        Depends on who you talk to. Note that Chiappe also tends to
"redefine" Ornithurae in a manner which is inconsistant with the original
definition (def. Gauthier: = {+ "modern birds", - _Arcaheopteryx_}).

        :)
        Wagner
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    Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
        "Chimp here does the killing." - Doug Mackenzie