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Phobetor and Giraffatitan (was RE: Dinosauria - Oops)




Michael Mortimer wrote:

The only dsungaripterid Unwin and Bakhurina (2000) report from anywhere in Mongolia is "Phobetor" parvus, which was previously named Dsungaripterus parvus.

Has this pterosaur been renamed _Phobetopter_? (Since the name _Phobetor_ Bakhurina 1986 was preoccupied by a genus of fish, _Phobetor_ Krøyer 1844, the pterosaur needed a new genus name.)


On the subject of names, Gregory S. Paul wrote:

In the 2nd Dinosauria I see that they list my (subgenus) Giraffatitan 1988 as
G. altithorax, which is impossible because B. altithorax is the type of the
genus. Instead it is B. (Giraffatitan) brancai.

This is one of a number of snafu's in Dinosauria II. For example, I also noticed that the Spanish ornithopod _Pararhabdodon_ is not mentioned in any of the taxonomic chapters, although it does appear in the Dinosaur Distribution chapter. There are other pesky mistakes too - none of which detract from the overall excellent quality of the volume.


As for _Giraffatitan_, I think there is a strong case for raising it to a new genus rather than persisting with the use of "subgenus" _Giraffatitan_. In that case, the Morrison and Tendaguru brachiosaurs would each represent a separate genus. I don't think there is a compelling case for uniting the two species (_altithorax_ and _brancai_) into a single genus - at least to the exclusion of other brachiosaurid taxa (e.g., _Atlasaurus_, _Pelorosaurus_, _Sauroposeison_). Salgado et al. (1997) found that the characters traditionally used to refer _brancai_ to _Brachiosaurus_ are primitive titanosauriform traits (although other studies disagree, e.g., Wilson and Sereno [1998], Naish et al.[2004]). Also, the validity of one character that has been traditionally used to unite _altithorax_ and _brancai_ (humerus at least as long as the femur) has been questioned, since the humerus of _B. brancai_ is apparently incomplete. At any rate, this character is also found in _Atlasaurus_ (and maybe at least one European brachiosaur).

If the titanosauriform skull USNM 5730 (described by Carpenter and Tidwell, 1998) is referrable to _B. altithorax_, then both species would share a similar skull morphology (including the "stepped", subrectangular muzzle). However, in other respects, USNM 5730 is intermediate between the skulls of _Camarasaurus_ and _B. brancai_, especially in the snout (shorter maxilla with more teeth), organization of the skull roof elements, and perhaps in the dentition too (the only known tooth of USNM 5730 is more like the teeth of_Camarasaurus_ than _B. altithorax_).




Tim