Integrated phylogenetic analysis of south-eastern mud turtles ( <i>Kinosternon</i> ) using genomic data and morphology supports deep divergence and species status for the Mississippi mud turtle ( <i>Kinosternon hippocrepis</i> Gray, 1856)

Abstract The south-eastern United States is a hotspot of diversity for many taxa, including turtles (order Testudines). Comparative phylogeography has identified the Mississippi River Basin as a biogeographic barrier contributing to the evolution of that diversity. South-eastern mud turtles (Kinosternon subrubrum group) have a complicated taxonomic history, with previous revisions elevating two morphologically distinct taxa inhabiting the eastern part of the range to species status, while retaining a single species designation for other turtles ranging from the Atlantic coast to the edge of the Great Plains. Using molecular data, we confirm a deep primary divergence within the K. subrubrum group corresponding with the Mississippi Basin. Morphological data confirm that turtles in the western group are distinguishable from taxa east of the Mississippi based on multiple characters, although females, in particular, show morphological conservatism among taxa. Based on these results, we propose restoring the Mississippi mud turtle to species status (Kinosternon hippocrepis).