Tim Williams schrieb:
I do think Mike makes a good case for making the east African _brancai_ a separate genus from the North American _altithorax_. Apart from the reasons stated in Taylor (2009), this also dispels the much vaunted faunal association between the Tendaguru and Morrison Formations. For a long time, these two formations were thought to share a common fauna, which (in turn) was cited in support of a privileged connection between east Africa and western North America during the later Jurassic. With other "common" Tendaguru-Morrison genera likewise split up (_Barosaurus_/_Tornieria_, _Dryosaurus_/_Dysalotosaurus_), it was only a matter of time before _Brachiosaurus_ went the same way.yeah, there is a distinct difference between the two, just think of Kentrosaurus and Stegosaurus.
However, I certainly don't agree that all genera should be monospecific. Using that logic, _Psittacosaurus_ would have to be split up into six or seven (or whatever) genera, which does not seem justified.
and if we were talking ungulates, then there WOULD be 7 different genera.same yardstick for all, I'd say, and if so, then splitting is better than lumping.
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