Data from: Historical species distribution models predict species limits in western Plethodon salamanders

Allopatry is commonly used to predict boundaries in species delimitation
investigations under the assumption that currently allopatric
distributions are indicative of reproductive isolation; however, species
ranges are known to change over time. Incorporating a temporal perspective
of geographic distributions should improve species delimitation; to
explore this, we investigate three species of western Plethodon
salamanders that have shifted their ranges since the end of the
Pleistocene. We generate species distribution models (SDM) of the current
range, hindcast these models onto a climatic model 21 Ka, and use three
molecular approaches to delimit species in an integrated fashion. In
contrast to expectations based on the current distribution, we detect no
independent lineages in species with allopatric and patchy distributions
(Plethodon vandykei and Plethodon larselli). The SDMs indicate that
probable habitat is more expansive than their current range, especially
during the last glacial maximum (LGM) (21 Ka). However, with a contiguous
distribution, two independent lineages were detected in Plethodon
idahoensis, possibly due to isolation in multiple glacial refugia. Results
indicate that historical SDMs are a better predictor of species boundaries
than current distributions, and strongly imply that researchers should
incorporate SDM and hindcasting into their investigations and the
development of species hypotheses.