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Re: Dinosaur and pterosaur head crest evolution by sexual selection

PDF rec'd.

Lee Hall
SWCA Environmental Consultants

On Mon, Dec 19, 2011 at 9:54 AM, Ben Creisler <bscreisler@yahoo.com> wrote:
> From: Ben Creisler
> bscreisler@yahoo.com
> A new online paper:
> Does mutual sexual selection explain the evolution of head crests in 
> pterosaurs and dinosaurs?
> Lethaia (advance online publication)
> DOI: 10.1111/j.1502-3931.2011.00300.x
> http://onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.2011.00300.x/abstract
> Cranial ornamentation is widespread throughout the extinct non-avialian 
> Ornithodira, being present throughout Pterosauria, Ornithischia and 
> Saurischia. Ornaments take many forms, and can be composed of at least a 
> dozen different skull bones, indicating multiple origins. Many of these 
> crests serve no clear survival function and it has been suggested that their 
> primary use was for species recognition or sexual display. The distribution 
> within Ornithodira and the form and position of these crests suggest sexual 
> selection as a key factor, although the role of the latter has often been 
> rejected on the grounds of an apparent lack of sexual dimorphism in many 
> species. Surprisingly, the phenomenon of mutual sexual selection -- where 
> both males and females are ornamented and both select mates -- has been 
> ignored in research on fossil ornithodirans, despite a rich history of 
> research and frequent expression in modern birds. Here, we review the 
> available evidence
>  for the functions of ornithodiran cranial crests and conclude that mutual 
> sexual selection presents a valid hypothesis for their presence and 
> distribution. The integration of mutual sexual selection into future studies 
> is critical to our understanding of ornithodiran ecology, evolution and 
> particularly questions regarding sexual dimorphism.