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Re: Quaesitosaurus and Nemegtosaurus



In a message dated 96-12-07 17:31:50 EST, RaptorRKC@aol.com writes:

> Would it be improbable to restore either of the dinosaurs referred
> to in the subject line with a body similar to that of
> Opisthocoelicaudia?

Not in the least. This was first suggested by Greg Paul several years ago.
Initially, other workers tended to disagree, because the postcranial skeleton
of _O._ has many features found among camarasaurids, whereas the skulls of
_N._ and _Q._ seemed to be diplodocoid. A recent reconstruction of the skull
of _N._, however, suggests close affinities with brachiosaurids, therefore
also camarasaurids, whereas Upchurch's cladistic study places _N._ and _Q._
in their own family, Nemegtosauridae, as a basal sister group to diplodocids.
These studies move _N._ and _Q._ significantly closer to _O._
phylogenetically. In view of the fact that there most likely were
transitional sauropods between camarasaurids and diplodocids (as yet unknown
in the fossil record but inferred from sauropod phylogeny), we may speculate
that nemegtosaurids derived from such camarasaurid-diplodocid transitional
forms. This would account for the camarasaurid and diplodocid features
present among  _O._, _Q._,and _N._, and also greatly increases the likelihood
that _O._ and _N._ belong to the same sauropod genus (named _Nemegtosaurus_
by priority and to which _Q._ is an earlier sister group).