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dino numbers



Thank you Dinogeorge for your thoughtful essay on this topic.
I have a couyple of criticisms.  The first refers to the number
of small dinos not fossilized.  My own observations in Alberta
have shown vast numbers of teeth of small mammals in some of
the bone beds, but none of small reptiles (I am old fashioned
and still use this general name, despite the cladists).  This
suggest to me that in this locality at least all the dinos
were big boys, and the niches for small animals were filled
by mammals.  That's small _vertbrates_ not small _animals_.

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
liberal.

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

David

--
>From: David Brez Carlisle
bk090@Freenet Carleton.CA