Latest K dinosaurian diversity trends (was Re: Titanoceratops, giant ceratopsian from New Mexico)

[tholtz@geol.umd.edu]

>
> While I don't have the reference at hand, I recall papers on the latest
> Cretaceous dinosaur faunas in Europe that claim the diminution seen in
> North America for that time is not the pattern seen in Europe.  Is it
> possible that this is a North American phenomenon?
>
> Dan

Of course the big problem with Late K European dinosaurs is sort out to
what degree the differences between faunas is stratigraphic changes, and
to what degree the fact you are sampling distinct island faunas.

One thing that Denver has alluded to--and which was shown in several SVP
presentations--is that the high-resolution GIS data of dig sites coupled
with high resolution stratigraphy in well-studied formations (Dinosaur
Park, Hell Creek, etc.) is showing that many dinosaur species of the same
faunal stage/NALMA/whatever you want to call it are NOT contemporaries at
all. Instead, they are falling in distinct very short phases. So it may
well be that throughout the Campanian and Maastrichtian (for instance)
there was never more than one or two comtemporaneous centrosaurine species
in the same region, only one or two chasmosaurines, etc.