Re: dinos and birds

[Mickey Mortimer <Mickey_Mortimer111@msn.com>]

Dora Smith wrote-

> Actually birds belong to a large family of warm-blooded reptiles, and a
> subgroup of those that had feathers.   Not merely descendants of.

Well, they are both the descendants of earlier reptiles, and reptiles
themselves.

> I do wonder whether it is time to subdivide them.   Reptiles differ almost
> as much from each other as oxygen-breathing organisms from other primitive
> life.

Done and done.

Assuming turtles are relatives of pareiasaurs, reptiles are subdivided into
two groups-
Parareptilia / Anapsida / Progonosauria - containing turtles, pareiasaurs,
procolophonids, and mesosaurs(?).
Eureptilia / Romeriida - containing lizards, snakes, sphenodonts,
plesiosaurs, placodonts, ichthyosaurs, pterosaurs, crocodilians, and birds
and other dinosaurs.

Assuming turtles are diapsids instead, reptiles are divided into two
different groups-
Lepidosauromorpha - containing lizards, snakes, sphenodonts, plesiosaurs,
placodonts, ichthyosaurs, and perhaps turtles.
Archosauromorpha - containing pterosaurs, crocodilians, birds and other
dinosaurs, and perhaps turtles.

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html