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Titanosaurus v Jainosaurus (was Alamosaurus as biggest North American sauropod)

David Marjanovic <david.marjanovic@gmx.at> wrote:

> Carpenter & Tidwell seem to have thought "if there's no evidence for
> multiple taxa, don't split". Wilson & Upchurch seem to have thought "if
> there's no evidence for lumping, don't sink established names, even when
> there's no evidence that would support splitting either". Both agree "if
> there's no evidence, don't act" -- they just disagree on what counts as
> acting...

Alas, it's not quite so simple.  The Arundel material and Bara Simla
material had each been previously split into two genera: _Astrodon_ +
_Pleurocoelus_, and _Titanosaurus_ + _Jainosaurus_.  So there really
is no real difference in the historical contexts.

For the Lameta sauropod material from Bara Simla, there had actually
been differing views over whether one or two sauropod species were
represented.  Matley (1921) initially thought that only one sauropod
individual was represented.  It was Huene (in Huene and Matley, 1933)
who first decided to divide the material into two species, and erected
_Antarctosaurus septentrionalis_ in addition to _Titanosaurus
indicus_.  Jain and Bandhyopadhay (1997) referred _Antarctosaurus
septentrionalis_ to _T. indicus_.

Even though Huene's reasons for splitting the Bara Simla material were
recognized as spurious, Wilson and Upchurch (2003) nevertheless kept
the two species separate.   Furthermore, because the name
_Jainosaurus_ was available for _Antarctosaurus septentrionalis_,
subsequent studies have regarded _Jainosaurus septentrionalis_ as the
only valid titanosaur species from Bara Simla.  By contrast, _T.
indicus_ has been consigned to the dustbin, as a nomen dubium.  If I
was _T. indicus_, I'd be feeling a little hard done by.  :-(