Re: DROMORNITHIDS, RATITES etc.

["Timothy Williams" <twilliams_alpha@hotmail.com>]

Darren Naish wrote:

> Ratites (IMHO) are not closely related to anseriforms, but are rather
> the sister-group to the neognaths (Galloanserae, Turnicae, Picae,
> Coraciae, Coliae and Passerae of S & A 1990). Though some
> ornithologists still hold out for a polyphyletic view of ratite evolution,
> the idea that the group is monophyletic and outside of Neognathae is
> well supported.


Kurochkin, for one, regards the ratites (and tinamous) as more closely 
related to the extinct _Ambiortus and _Otogornis_ (Cretaceous) and the 
_Lithornis_ group (early Tertiary) than to any other Recent orders.  This 
idea also has been kicking around for a while.  (Kurochkin contradicts the 
view that _Ambiortus_ might be closely related to the ichthyornithids.)  
Kurochkin includes all these groups (Ambiortiformes, Lithornithiformes, 
Tinamiformes, ratites) in the Palaeognathae, the sister clade to the 
Neognathae.

P.S. Can anyone give me a definition of "heterocoelous"?  And while on the 
topic of vertebrae, what is the difference between "amphiplatyan" and 
"platycoelous"?


References

Kurochkin, Evgeny N. (1999).  The relationships of the Early Cretaceous 
_Ambiortus_ and _Otogornis_ (Aves: Ambiortiformes).  Smithsonian 
Contributions to Paleobiology.  89: 275-284.


Tim
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