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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
>I still stick with my own estimate of about 100 species
>at any one time.

100 species is almost certainly far too low. We often get 20-30 species
(though many are unidentifiable because of incomplete preservation) in a
_single formation_, let alone over the _whole earth_.