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Re: dino numbers

In a message dated 95-10-08 03:33:49 EDT, bk090@freenet.carleton.ca (David
Brez Carlisle) writes:

>The second point is the estimate of the number of species
>per genus.  Among extant mammals and birds certainly a few
>genera contain over 20 species, but far more are monotypic.
>The mean is less than 2 species per genus.  You are
>being far too generous then, George, in estimating many
>polytypic genera among the dinos.  EVen if Peter Dodson's
>estimates are conservative I think yours are far too

That may be simply because any one genus only contains a few species in any
one period. Many extant mammalian genera are highly polytypic when you add in
the extinct species for each genus. Don't forget about them.