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Re: How long for Genus

In a message dated 97-02-05 12:55:08 EST, you write:

> Example: the genus Allosaurus?
>  Could this genus have lasted into the late Early Cretaceous? about 20
>  million year gap between Late Jurassic _Allosaurus fragilis_ and
>  Australia's Early Cretaceous _Allosaurus robustus_.

That does seem a very long time let alone the distance for the genus
Allosaurus! Marsh had made the mistake of assigning the name 'Allosaurus
medius' to a  large theropod tooth found in the Arundel Clay Formation
(Aptian) of Maryland beliving that the horizon was of Jurasic age. Then it
was assigned to Dryptosaurus medius. a  Late Cretaceous genus! I believe that
when the dust settles on the Arundel material that it will turn out to be
relative of, if not, Acrocanthosaurus, an Allosaurid! But stranger things
have happened.

My humble 2 cents...

Thomas R. Lipka
Paleontological/Geological Studies