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Re: Laelaps and Brontosauria (was Re: Resending)

--- Tim Williams <twilliams_alpha@hotmail.com> wrote:

> You are correct when you say that Olshevsky put ALL prosauropods and 
> sauropods into his Brontosauria.  In fact, the only real reason Olshevsky 
> erected "Brontosauria" was because he also thought segnosaurs were 
> sauropodomorphs, and he need a name for the non-segnosaur sauropodomorphs.  
> Take out the Segnosauria (as he later did), and 
> Brontosauria=Sauropodomorpha.

Why not just abandon Brontosauria? It's original announcement was because of a 
relationship between therizinosaurs and sauropodomorphs. Clearly, no one is 
advocating that anymore. 
Also, it's based on Brontosaurus, itself invalid by synonymy. 
We already have the names Plateosauridae, Plateosauria, Prosauropoda, 
Anchisauria - The topologies
of all of which could change following a revision in cladistics. Eg. 
Anchisauria originally
proposed in 2004 for the Anchisaurus + Melanorosaurus clade assumed a close 
relationship between
these taxa; now 1 year latter, Anchisauria could include Anchisaurus and all 
other sauropodomorphs
excluding Saturnalia, Thecodontosaurus, Plateosauridae, & Massospondylus. See
http://dml.cmnh.org/2005Aug/msg00240.html for this.

If topolgies are changing all the time, i'd take that to mean that the 
relationships aren't
stable. Until they become stable, i see little point in introducing new names 
reusing/redefining redundant names beyond their original context. 

> Thus, a Prosauropoda+Sauropoda clade under current topologies would not have 
> *exactly* the same content as Brontosauria sensu Olshevsky.  However, I 
> tip-toed around this by saying the new Brontosauria would have 
> *approximately* the same content as the old.  A few basal sauropodomorphs 
> would certainly fall out - but probably no more than two or three 
> (_Thecodontosaurus_, etc) , and the vast majority of sauropodomorphs would 
> stay inside Brontosauria.  So, this new Brontosauria would retain almost all 
> of its original content.  And what's a few genera between friends?  :-)
> Cheers
> Tim

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