Re: Giant birds

["T. Mike Keesey" <tkeese1@gl.umbc.edu>]

On Tue, 9 Nov 1999 Dinogeorge@aol.com wrote:

> In a message dated 11/9/99 1:33:22 PM EST, tkeese1@gl.umbc.edu writes:
> 
> << Of course, most people use Ornithosuchia and Pseudosuchia for these taxa
>  (not great names, but, IMHO, neither are Aves and Thecodontia).>>
> 
> Aves and Thecodontia at least have priority over Ornithosuchia and 
> Pseudosuchia, respectively.

Well, Amniota has priority over Alvarezsauria, but it doesn't mean they're
the same taxon.

> Plus Pseudosuchia ("false crocodiles") includes true crocodiles.

Terrible name, yeah, but calling ankylosaurs "birds" is pretty bad, too.

> << If you call {Neornithes > _Crocodylus_} Aves, shouldn't you call
>  {_Crocodylus_ > Neornithes} Crocodylia? >>
> 
> Good point; I could definitely live with that. Crocodylia has priority over 
> Thecodontia, too. I was thinking in terms of crocs being derived 
> thecodontians, but it's just as easy to think of the early archosaurs as 
> primitive crocs.

Then _Dimetrodon_ is a primitive mammal, pareiasaurs are primitive
chelonians, etc. ...

I think it generally makes good sense to make taxa that were originally
based on extant forms into crown groups instead of stem groups. A few
exceptions here and there (like Aves).

--T. Michael Keesey
tkeese1@gl.umbc.edu | THE DINOSAURICON: http://dinosaur.umbc.edu/
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