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Pterosaur morphological diversity sampling in deep time



From: Ben Creisler
bh480@scn.org

A new paper that may not have been mentioned yet:

Richard J. Butler, Stephen L. Brusatte, Brian Andres, & Roger B. J. Benson
(2011)
HOW DO GEOLOGICAL SAMPLING BIASES AFFECT STUDIES OF MORPHOLOGICAL EVOLUTION
IN DEEP TIME? A CASE STUDY OF PTEROSAUR (REPTILIA: ARCHOSAURIA) DISPARITY.
Evolution (advance online publication)
DOI: 10.1111/j.1558-5646.2011.01415.x
http://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2011.01415.x/abstract


ABSTRACT
A fundamental contribution of paleobiology to macroevolutionary theory has
been the illumination of deep time patterns of diversification. However,
recent work has suggested that taxonomic diversity counts taken from the
fossil record may be strongly biased by uneven spatiotemporal sampling.
Although morphological diversity (disparity) is also frequently used to
examine evolutionary radiations, no empirical work has yet addressed how
disparity might be affected by uneven fossil record sampling. Here, we use
pterosaurs (Mesozoic flying reptiles) as an exemplar group to address this
problem. We calculate multiple disparity metrics based upon a comprehensive
anatomical dataset including a novel phylogenetic correction for missing
data, statistically compare these metrics to four geological sampling
proxies, and use multiple regression modelling to assess the importance of
uneven sampling and exceptional fossil deposits (Lagersttten). We find that
range-based disparity metrics are strongly affected by uneven fossil record
sampling, and should therefore be interpreted cautiously. The robustness of
variance-based metrics to sample size and geological sampling suggests that
they can be more confidently interpreted as reflecting true biological
signals. In addition, our results highlight the problem of high levels of
missing data for disparity analyses, indicating a pressing need for more
theoretical and empirical work.


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