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Timetree of lissamphibians



From: Ben Creisler
bcreisler@gmail.com


A new online non-dino paper of interest:

David Marjanović & Michel Laurin (2013)
An updated paleontological timetree of lissamphibians, with comments
on the anatomy of Jurassic crown-group salamanders (Urodela).
Historical Biology (advance online publication)
DOI:10.1080/08912963.2013.797972
http://www.tandfonline.com/doi/full/10.1080/08912963.2013.797972#.UdWJc_m1FcQ


We present an update of our time-calibrated supertree of extant and
extinct lissamphibians (Marjanović D, Laurin M. 2007. Fossils,
molecules, divergence times, and the origin of lissamphibians. Syst
Biol 56(3):369–388) and of the divergence dates that can be inferred
from it. The present version contains 319 extinct species or possible
species of lissamphibians, compared to 223 previously. Discoveries of
new fossiliferous sites, advances in phylogeny and recently obtained
radiometric dates have offered opportunities to test our results,
including the conclusion that the fossil record of Lissamphibia is
dense enough to provide reliable calibration constraints for molecular
divergence dating. By and large, the results are upheld. Some of the
divergence dates we infer from the tree are up to 15 Ma younger than
we previously published, some are up to 15 Ma older, some have had
their range of uncertainty drastically reduced and the maximum age for
the origin of Urodela (the salamander crown group) is no longer well
constrained. The dermal bone plates in the gill region of the Jurassic
urodeles Beiyanerpeton, Seminobatrachus and Chunerpeton and the
grooves for the lateral line organ on the skull of the first require
either unexpected reversals or several independent losses in other
lissamphibians and indeed other urodeles.