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Re: The island rule: made to be broken?



I think they missed a group (clade?) that may be
paricularly relevant to dinosaurs.  Pygmy elephants
are well-known from the islands off California and, if
memory is correct, from Mediterranean islands.

Glen Ledingham

 
--- Tim Williams <twilliams_alpha@hotmail.com> wrote:

> 
> 
> 
> This is plausibly relevant to dinosaurs, given that
> the issue of insular dwarfism has come up for
> European dinosaurs (e.g., _Europasasaurus_,
> _Magyarosaurus_, _Telmatosaurus_, _Struthiosaurus_).
>  This new Proc. R. Soc. B. paper says that the
> "island rule" is actually quite shaky.  (For
> mammals, anyway.)
> 
> 
> 
> 
> Shai Meiri, Natalie Cooper & Andy Purvis (2007). 
> The island rule: made to be broken?  Proceedings of
> The Royal Society B. FirstCite Early Online
> Publishing 
> 
> Abstract: "The island rule is a hypothesis whereby
> small mammals evolve larger size on islands while
> large insular mammals dwarf. The rule is believed to
> emanate from small mammals growing larger to control
> more resources and enhance metabolic efficiency,
> while large mammals evolve smaller size to reduce
> resource requirements and increase reproductive
> output. We show that there is no evidence for the
> existence of the island rule when phylogenetic
> comparative methods are applied to a large,
> high-quality dataset. Rather, there are just a few
> clade-specific patterns: carnivores; heteromyid
> rodents; and artiodactyls typically evolve smaller
> size on islands whereas murid rodents usually grow
> larger. The island rule is probably an artefact of
> comparing distantly related groups showing
> clade-specific responses to insularity. Instead of a
> rule, size evolution on islands is likely to be
> governed by the biotic and abiotic characteristics
> of different islands, the biology of the species in
>  question and contingency."
> 
>
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