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Re: Adios, "Brachiosaurus" brancai
> I believe so. Not that this is the final word or anything, but one recent
> study noted that the genus _Psittacosaurus_ is extremely conservative.
> Sereno et al. (2009; Proc. R. Soc. B doi: 10.1098/rspb.2009.0691):
> "Psittacosaurus is the most diverse dinosaurian genus with at least nine
> species after a conservative taxonomic revision (Sereno 2009). The genus is
> speciose because nearly all taxonomic differentia are limited to relatively
> minor tooth or cranial bone ornamentation. Variation in tooth replacement
> rate or jaw morphology is negligible compared to that seen in closely related
> basal neoceratopsians. The psittacosaur postcranial skeleton, in addition, is
> remarkably uniform."
> If Lukas's analysis holds up, then it would be an argument to sink
> _Hongshanosaurus_ into _Psittacosaurus_, rather than create at least eight
> new psittacosaurid genera.
Being a splitter, I would simply refer the specie mentioned above to
The relationships of the remaining species are still confused, but I think that
this has to do with the great amount of missing data. Psittacosaurus as
conceived today, is (in my subjective opinion) a wastebasket for a plethora of
small sized ceratopsians. Obviously, this is only a matter of taste, but do we
put Pachyrhinosaurus, Achelousaurus, Einiosaurus,and Styracosaurus within
Centrosaurus? These centrosaurines differ only by cranial ornamentation, their
skull anatomy, and their postacrania are almost the same (although Rebecca
Foster could disagree...); this can't be told for Psittacosaurus, which show
differencies in vertebral count, pelvic and cranial anatomy and so on.