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Tim wrote-
Recent research suggests that
diplodocoids disappeared from Patagonia by the Coniacian, replaced by derived
titanosaurs. In light of this, and research by Curry Rogers indicating
that Nemegtosaurus is a titanosaur, despite diplodocoid-like skull
features, isn't it most likely that Antarctosaurus includes material from
a diplodocoid-like titanosaur, rather than a true diplodocoid?
At least one diplodocoid (Sciutto and Martinez,
1994) survived in Argentina past the Coniacian. This diplodocid is
reported from the Maastrichtian and is said to have elongated neural
spines. Tom Holtz originally mentioned this taxon back in 1995 on the list,
so perhaps he knows more (like the papers citation).
In any case, Antarctosaurus' cranial remains share
derived characters with Nigersaurus, which allies it with rebbachisaurids rather
strongly.
Mickey Mortimer
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