RE: Bakker's Brontosaurus and Late Cretaceous populations

[Tim Williams <twilliams_alpha@hotmail.com>]

Mike Lima wrote:

> A couple years back I had heard that Bakker considered Brontosaurus a valid 
> genus separate from Apatosaurus and had tried to find out what anatomical 
> differences he noted between the two genera but couldn't find anything 
> beyond statements to the effect of "Dr. Bakker is finding evidence to 
> support his claim that Brontosaurus is a valid genus." Now a couple years 
> later, I tried to find more on the subject but I'm still only finding 
> similar vague statements. Has Bakker ever published or even stated on what 
> grounds he distinguishes between the two?

In 1998, Bakker did publish a study that mentioned a skull (TATE 099) that 
he referred to _A. excelsus_.  (This was in his "Dinosaur Mid-Life Crisis" 
paper, which also erected the new genus _Eobrontosaurus_ for _A. yahnahpin_) 
 He argued that the differences between TATE 099 and the skull of _A. ajax_ 
(CM 11162) were sufficient to justify generic separation; thus, he revived 
the genus _Brontosaurus_ for _excelsus_.  However, Bakker did not actually 
describe the new skull, nor give reasons why it should be referred to _A. 
excelsus_ (= Bakker's _Brontosaurus excelsus_).  I haven't seen or heard 
anything more on this.

Cheers

Tim