Re: Cursorial adaptations (was T.rex and elephants)

[Pieter.Depuydt@rug.ac.be]

Dann wrote:
> An interesting point, although the problem with many of
> the counter-balancing crest theories is that you often get closely
> related species with much smaller crests. The crest of Pteranodon
> sternbergi is much larger than P.ingens, and the closely related
> Nyctosaurus has barely a crest to speak of. The much larger
> Quezelcoatlus has an even smaller crest.
>       I would argue that styracosaurus had a much heavier
> and more cumbersome frill in life than its female counterparts.
> Similarly, is there enough difference between the front ends of the
> skulls of torosaurus and triceratops to suggest that torosaurus
> needed the counter-balance? With such cases of overkill it would
> seem that display formed a significant part of the function of the
> frills.

Very plausible indeed. At least in Protoceratops, there is some 
evidence of sexual dimorphism, with males having more pronounced and 
rather 'upturned' frills. 
Ceratopian frills also might have been quite convenient to get rid of 
excess body heat in those fairly compact animals living in those hot 
Late Cretaceous times. (I remember  a Nature publication from the
'post Bakker-Ostrom' late eighties (have to look up the reference, 
don't remember the author) in which various dinosaur novelties were 
reviewed as having a thermoregulatory (in casu cooling) function).

Regards,

Pieter Depuydt