Re: tendaguru question???

["Mickey Mortimer" <Mickey_Mortimer111@msn.com>]

David Carrizosa wrote-

> It was supposed before that tendaguru was like the morrison formation,
and they used to share dinosaurs like brachiosaurus, barosaurus, allosaurus,
dryosaurus
& ceratosaurus. but after that the barosaurus remains are unofficial called
tornieria,
and the theropods are quite indeterminate and brachiosaurus brancai probably
will
sunk into giraffatitan, what would happen with dryosaurus lettowvorbecki
it's still
considered as the same genus as dryosaurus, or someone think that needs also
reexamination and probably would sunk into dysalotosaurus how it was
previous known,
or is too fragmentary the remains to make a good comparision.

Well, some of the Tendaguru ceratosaurid stuff could really be Ceratosaurus
(though it's difficult to tell based on the fragmentary remains).
Similarly, Elaphrosaurus is known from the Morrison too (humerus, proximal
tibia), as E. "philtippettorum".  Both have basal tyrannosauroids
(Stokesosaurus; undescribed tooth) and small avian-like taxa ("Paleopteryx";
Archaeopteryx? metacarpal).  Also note the amount of theropod remains
described from the Tendaguru is really quite limited, so I wouldn't be
surprised to find Allosaurus, Torvosaurus, etc. there in the future.
Most importantly, however, choices as to whether Tendaguru species belong to
Morrison genera are largely subjective at this point in our understanding
anyway.  The more fragmentary something is, the fewer characters it will
appear to differ from its relative in.  If Tarbosaurus were only known from
an ilium, it would probably just be called Tyrannosaurus.  If Giganotosaurus
was just known from a postorbital, it might be called Carcharodontosaurus.
So while roechlingi and stechowi would be called Ceratosaurus if found in
the Morrison, and are more similar to Ceratosaurus than other described
genera, more complete specimens could always result in the discovery of more
differences than we feel comfortable with placing in Ceratosaurus.  Also, I
don't think any of the Tendaguru species have been shown to be in an
exclusive monophyletic group with their Morrison counterparts.  To the
contrary, Brachiosaurus and Giraffatitan were shown to be paraphyletic to
titanosaurs in one (the only?) study.  Sure, Dysalotosaurus is a lot like
Dryosaurus, but is it more closely related to Dryosaurus than either is to
Valdosaurus, or Kangnasaurus?  No one knows yet.  Finally, even if the
species are sister groups, deciding whether they are congeneric is
subjective in itself.
In any case, the Tendaguru does seem to be very similar to the Morrison, as
are Guimarota and Lourinha in Portugal.  The Shangshaximiao (China) is quite
different however.  Exactly how much the Canadon Clacareo (Argentina)
resembles either is uncertain, though it does have a dicraeosaurid.
As for your question, Dysalotosaurus is known from pretty complete remains.
Several individuals, including good skull material.  And I have seen it
called Dysalotosaurus a few times recently.
By the way, Barosaurus africanus and B. gracilis are not just unofficially
called Tornieria, africanus being the type species of Tornieria after all.
Incidentally, Sereno and Wilson's (2001) cladistic analysis couldn't
determine whether africanus was more closely related to Barosaurus or
Diplodocus.

Mickey Mortimer