[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
A while ago I asked how many species are currently recognised for the
genus _Triceratops_. It's a fairly esoteric question, and probably
no-one really knows exactly. But, it's probably more than just a
matter for taxonomy.
A lot of authors have pointed to a loss of dinosaur diversity in the
final few million years of the Mesozoic as evidence for a gradual
decline before their final extinction, rather than a single great
catastrophe at the K/T boundary. In other words, late Maastrichtian
sites (particularly in North America) are said by some to be dominated
by large numbers of fossils of a few species, while in
stratigraphically earlier sites, species are represented by less
fossil material, but there larger numbers of species per site.
But this "loss of diversity" could be an artifact of taxonomy. For
example, in western North America, _Triceratops horridus_ is said to
be the dominant ceratopsian during the late Maastrichtian. But this
taxon could embrace a number of _Triceratops_-like species (or even
genera, like _Diceratops_ or _Ugrosaurus_). Similarly, there could be
at least three _Tyrannosaurus_-like genera in the latest Maastrichtian
- _Tyrannosaurus_, _Dinotyrannus_, _Nanotyrannus_ - rather than just
one genus and species (_T. rex_).
Any ideas?? Is this a load of @#$@#?