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Re: Ornithopsida (was Re: Dinosauria---Rejected Name?)

In a message dated 2/23/02 9:36:05 PM Eastern Standard Time, 
n_gardner637@hotmail.com writes:

> Is this what you put in your groups?
>  Theropsida = Mammals, "Pelycosaurs", Therapsids
>  Chelonopsida = Turtles and more basal anapsids
>  Herpetopsida = Lepidosaurs
>  Suchopsida = Crocodiles and their extinct relatives
>  Ornithopsida = Dinosaurs (inc. Birds) and Pterosaurs

Pretty much.  They all had definitions like the following:

Ornithopsida = all amniotes more closely related to modern birds than to 
modern mammals, modern turtles, modern snakes, or modern crocodiles.  

Thus, the content might change depending on your phylogenetic hypothesis.  If 
turtles are archosaurs, Chelonopsida would be a subgroup of archosauria, and 
pareiasaurs, etc., would be outside any of the groups named above.  
Similarly, if pterosaurs are derived prolacertiforms, they would not fall 
into any of the five groups.

--Nick P.