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Variation in theropod dinosaur skull evolution rates significant in oviraptorosaurs



Ben Creisler
bcreisler@gmail.com


A new online paper:



J. A. F. Diniz-Filho, D. M. C. C. Alves, F. Villalobos, M. Sakamoto,
S. L. Brusatte and L. M. Bini (2015)
Phylogenetic eigenvectors and non-stationarity in the evolution of
theropod dinosaur skulls.
JOURNAL OF EVOLUTIONARY BIOLOGY (advance online publication)
DOI: 10.1111/jeb.12660
http://onlinelibrary.wiley.com/doi/10.1111/jeb.12660/abstract


Despite the longstanding interest in non-stationarity of both
phenotypic evolution and diversification rates, only recently have
methods been developed to study this property. Here, we propose a
methodological expansion of the Phylogenetic Signal Representation
(PSR) curve based on phylogenetic eigenvectors to test for
non-stationarity. The PSR is built by plotting the coefficients of
determination R2 from Phylogenetic Eigenvector Regression (PVR) models
increasing the number of phylogenetic eigenvectors against the
accumulated eigenvalues. The PSR curve is linear under a stationary
model of trait evolution (i.e., the Brownian motion model). Here we
describe the distribution of shifts in the models R2 and used a
randomization procedure to compare observed and simulated shifts along
the PSR curve, which allowed detecting non-stationarity in trait
evolution. As an applied example, we show that the main evolutionary
pattern of variation in the theropod dinosaur skull was
non-stationary, with a significant shift in evolutionary rates in
derived oviraptorosaurs, an aberrant group of mostly toothless,
crested, bird-like theropods. This result is also supported by a
recently proposed Bayesian-based method (AUTEUR). A significant
deviation between Ceratosaurus and Limusaurus terminal branches was
also detected. We purport that our new approach is a valuable tool for
evolutionary biologists, owing to its simplicity, flexibility and
comprehensiveness.




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