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Re: Abydosaurus mcintoshi, a new sauropod from the Albian of Utah
Mike Taylor <email@example.com> wrote:
> But I do think it's enough evidence to have shifted the null hypothesis
> -- so that anyone who wants to challenge it really ought to make the
> effort to dig out some actual evidence themselves. What Chure et al.
> wrote -- "the identified differences have not been defended as
> separating genera, rather than species, populations, or individuals"
> -- really doesn't advance the discussion at all. It's an argument from
> laziness, and all it does is muddy the waters (and perpetuate the
> discredited notion that the Morrison and Tendaguru formations shared a
The discovery of _Abydosaurus_ might actually have provided a good opportunity
to test the monophyly of _altithorax_+_brancai_. Instead, this monophyly was
simply assumed by Chure &c, and _altithorax_+_brancai_ were therefore treated
as a single OTU (_Brachiosaurus_) in the phylogenetic analysis.
Also, as mentioned by Mike, _altithorax_ is from the Morrison, and _brancai_ is
from the Tendaguru. Thus, I would have thought that lumping the two into a
single genus would require compelling morphological evidence. This isn't the
case. IMHO, Taylor (2009) established a strong case for treating _brancai_ as
a separate genus (_Giraffatitan_). It's only historical tradition that's
holding the two together. If Janensch had *not* referred _brancai_ to
_Brachiosaurus_, but had instead erected a separate genus, we wouldn't be
having this discussion.