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Crocodylus is not "living fossil"



From: Ben Creisler
bh480@scn.org

Not really dinosaurs, but could be of interest to the DML:

Jamie R. Oaks (2011)
A TIME-CALIBRATED SPECIES TREE OF CROCODYLIA REVEALS A RECENT RADIATION OF
THE TRUE CROCODILES.
Evolution (advance online publication)
DOI: 10.1111/j.1558-5646.2011.01373.x
http://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2011.01373.x/abstract


True crocodiles (Crocodylus) are the most broadly distributed, ecologically
diverse, and species-rich crocodylian genus, comprising about half of
extant crocodylian diversity and exhibiting a circumtropical distribution.
Crocodylus traditionally has been viewed as an ancient group of
morphologically conserved species that originated in Africa prior to
continental breakup. In this study, these long-held notions about the
temporal and geographic origin of Crocodylus are tested using DNA sequence
data of 10 loci from 76 individuals representing all 23 crocodylian
species. I infer a time-calibrated species tree of all Crocodylia and
estimate the spatial pattern of diversification within Crocodylus. For the
first time, a fully resolved phylogenetic estimate of all Crocodylia is
well-supported. The results overturn traditional views of the evolution of
Crocodylus by demonstrating that the true crocodiles are not
?living-fossils? that originated in Africa. Rather, Crocodylus originated
from an ancestor in the tropics of the Late Miocene Indo-Pacific, and
rapidly radiated and dispersed around the globe during a period marked by
mass extinctions of fellow crocodylians. The findings also reveal more
diversity within the genus than is recognized by current taxonomy.



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