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Re: Dinosaur Genera List corrections #98
> Bakker, R. T., 1998. "Dinosaur Mid-Life Crisis: The Jurassic-Cretaceous
> Transition in Wyoming and Colorado," in Lucas, Kirkland, & Estep, J. W., eds.,
> 1998: 67 77.
> Bakker argues, with considerable justification, that the species _Apatosaurus
> yahnahpin_ Filla & Redman, 1994 should be removed from the genus _Apatosaurus_
> into its own new genus, _Eobrontosaurus_, as its type species _Eobrontosaurus
> yahnahpin_ (Filla & Redman, 1994) Bakker, 1998. He also argues, though
> somewhat less persuasively, that the genus _Brontosaurus_ should not have been
> sunk into _Apatosaurus_.
For those who are interested: judging from Bakker's paper, the
splitting of _Apatosaurus_ and _Brontosaurus_ is based upon features
(or one feature) of the braincase: position of the basitubera. This
is based upon a new-ish skull referred to _A. excelsus_ (type species
of _Brontosaurus_) compared to a skull previously referred to _A.
ajax_ (type species of _Apatosaurus_). A paper is in the works
(apparently) which described this more fully.
As Bakker himself mentions, and as pointed out by McIntosh (among
others), there is nothing postcranially that can be used to
distinguish _A. ajax_ from _A. excelsus_. Except that _A. ajax_ is
bigger (and lived later in time).