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numbers of dinos at any one time

Stan Friesen estimates that the number of valid e
described species of dinos is between 150 and 200.  He also 
suggests at total number of about 1,500, meaning no more than
about 10% have actually been desribed.

Asssuming the life of a species at 5 million years (which
about right for the carnivores at least), then 200 species in
185 million years means an average of about 5.4 species at
any one time.  If there were as many as 2,000 species this
calculation works out to an average of 40.5 species at any
one time.

It looks as if my estimates of a maximum of 25 _known_
species and a possible 100 species (including nondescripts)
was generous.


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