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Pterosaur evolution and Cope's rule (free pdf)

From: Ben Creisler

A new paper in open access:

Roger B. J. Benson, Rachel A. Frigot, Anjali Goswami, Brian Andres &
Richard J. Butler (2014)
Competition and constraint drove Cope's rule in the evolution of giant
flying reptiles.
Nature Communications 5, Article number: 3567

The pterosaurs, Mesozoic flying reptiles, attained wingspans of more
than 10 m that greatly exceed the largest birds and challenge our
understanding of size limits in flying animals. Pterosaurs have been
used to illustrate Cope’s rule, the influential generalization that
evolutionary lineages trend to increasingly large body sizes. However,
unambiguous examples of Cope’s rule operating on extended timescales
in large clades remain elusive, and the phylogenetic pattern and
possible drivers of pterosaur gigantism are uncertain. Here we show 70
million years of highly constrained early evolution, followed by
almost 80 million years of sustained, multi-lineage body size
increases in pterosaurs. These results are supported by
maximum-likelihood modelling of a comprehensive new pterosaur data
set. The transition between these macroevolutionary regimes is
coincident with the Early Cretaceous adaptive radiation of birds,
supporting controversial hypotheses of bird–pterosaur competition, and
suggesting that evolutionary competition can act as a
macroevolutionary driver on extended geological timescales.