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Re: Mesozoic birds lacked ecological diversity?



From: Ben Creisler
bcreisler@gmail.com

Here's the full ref and abstract:

Jonathan S. Mitchell and Peter J. Makovicky (2014)
Low ecological disparity in Early Cretaceous birds.
Proceedings of the Royal Society B 22 July 2014 vol. 281 no. 1787 20140608
doi: 10.1098/rspb.2014.0608
http://rspb.royalsocietypublishing.org/content/281/1787/20140608.abstract


Ecological divergence is thought to be coupled with evolutionary
radiations, yet the strength of this coupling is unclear. When birds
diversified ecologically has received much less attention than their
hotly debated crown divergence time. Here, we quantify how accurately
skeletal morphology can predict ecology in living and extinct birds,
and show that the earliest known assemblage of birds (= pygostylians)
from the Jehol Biota (≈ 125 Ma) was substantially impoverished
ecologically. The Jehol avifauna has few representatives of highly
preservable ecomorphs (e.g. aquatic forms) and a notable lack of
ecomorphological overlap with the pterosaur assemblage (e.g. no large
or aerially foraging pygostylians). Comparisons of the Jehol
functional diversity with modern and subfossil avian assemblages show
that taphonomic bias alone cannot explain the ecomorphological
impoverishment. However, evolutionary simulations suggest that the
constrained ecological diversity of the Early Cretaceous pygostylians
is consistent with what is expected from a relatively young radiation.
Regardless of the proximate biological explanation, the anomalously
low functional diversity of the Jehol birds is evidence both for
ecological vacancies in Cretaceous ecosystems, which were subsequently
filled by the radiation of crown Aves, and for discordance between
taxonomic richness and ecological diversity in the best-known Mesozoic
ecosystem.




On Tue, May 27, 2014 at 4:39 PM, Ben Creisler <bcreisler@gmail.com> wrote:
> From: Ben Creisler
> bcreisler@gmail.com
>
> A news story for a paper due out tomorrow:
>
> http://phys.org/news/2014-05-prehistoric-birds-lacked-diversity.html
>
> Paper (no active link as yet):
>
> Jonathan H. Mitchell and Peter J. Makovicky (2014)
> Low ecological disparity in early Cretaceous birds
> Proceedings of the Royal Society B (advance publication).
> rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2014.0608