RE: Latest K dinosaurian diversity trends

[Jaime Headden <qi_leong@hotmail.com>]

Denver Fowler wrote:

<I would say that the low morphological variation is probably reflective of 
true taxonomic diversity, and that most of the described taxonomic variation is 
actually ontogenetic or stratigraphic, (which are both testable hypotheses and 
not merely individual judgement calls). I'd love to go into further details of 
species in the Hell Creek, but its other people's (in progress) research.>

  In seeming contradiction to this, most variation in the domestic dog (*Canis 
lupus*) is not reflective of genetic differences and is certainly not reflected 
in taxonomy. It is also important to note that species diversity in, say, 
Corvidae, is based on non-skeletal features, mostly size-related, regional, 
habitual, etc. characteristics.

Cheers,

Jaime A. Headden
The Bite Stuff (site v2)
http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)





----------------------------------------
> Date: Sun, 2 Jan 2011 16:15:57 +0000
> From: df9465@yahoo.co.uk
> To: dinosaur@usc.edu
> Subject: Re: Latest K dinosaurian diversity trends
>
> ----- Original Message ----
>
> From: "Harris, Jerald" 
>
> DF
> >>you can split the only
> North American Late Maastrichtian hadrosaurid (Edmontosaurus) into 3 taxa if
> you like, but it's still only the one clade, whereas in the Campanian we had
> multiple clades (3-4 hadrosaurines, 3-4 lambeosaurines). So diversity is just
> modified by a multiplier depending on whether you are a splitter or not.
>
> JH
> > This doesn't make any sense. Using this same logic (using clades, rather
> than species, to define diversity), one could say that there's only one clade
> present in the Late Maastrichtian terrestrial gnathostome fauna: 
> Gnathostomata.
> Really low diversity, that. Or among arthropods, one could say that there's
> only Hexapoda.
>
> Yes, I'm not sure I have the words as to how to put this properly. Maybe this
> works: There is less morphological diversity among late Maastrichtian 
> dinosaurs
> compared to Late Campanian dinosaurs. Whether or not you split the taxa into
> multiple species does not alter this. I would say that the low morphological
> variation is probably reflective of true taxonomic diversity, and that most of
> the described taxonomic variation is actually ontogenetic or stratigraphic,
> (which are both testable hypotheses and not merely individual judgement 
> calls).
> I'd love to go into further details of species in the Hell Creek, but its 
> other
> people's (in progress) research.
>
>
>