Re: Latest K dinosaurian diversity trends

[Dann Pigdon <dannj@alphalink.com.au>]

On Mon, Jan 3rd, 2011 at 3:15 AM, Denver Fowler <df9465@yahoo.co.uk> wrote:

> 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.

If Maastrichtian dinosaurs had a tendancy towards greater ontogenetic 
variation, then I suppose 
morphological diversity could have been just as high in any given ecosystem - 
it's just that the 
diversity is encompassed by fewer actual species. Instead, the morphological 
variation is due to 
animals being at different life stages.

That assumes that large ontogenetic variation correlates with changes in 
behaviour and/or ecology 
throughout an individuals lifetime (which may or may not have been the case).

-- 
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Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
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