Meeting Abstract

P3.113  Thursday, Jan. 6  Phylogeography of the Cave-Obligate Millipede Genus Tetracion LORIA, Stephanie F.*; ZIGLER, Kirk S.; LEWIS, Julian J.; Sewanee: The University of the South; Sewanee: The University of the South; Lewis and Associates: Cave, Karst and Groundwater Biological Consulting LLC loriasf0@sewanee.edu

Millipedes are an understudied group. Little is known about their ecology, life history, and genetic diversity. Particularly neglected are the diverse cave millipedes of eastern North America. Understanding the patterns and processes that determine their distribution in this region is an area of recent research. Here, we present a phylogeographic study of the cave-obligate millipede genus Tetracion (Callipodida: Abacionidae). This genus inhabits caves on the Cumberland Plateau in Tennessee and Alabama, a hotspot for cave biodiversity. Three species have been described: T. jonesi and T. antraeum from northern Alabama and southern Tennessee, and T. tennesseensis from south-central Tennessee. To examine genetic divergence within and between species in this genus we sequenced part of the mitochondrial cytochrome oxidase 1 gene from 53 specimens from 11 caves across the ranges of T. jonesi and T. tennesseensis. We found: (1) 8% genetic divergence between T. tennessensis and T. jonesi, (2) little genetic variation (up to 1%) within each species, and (3) a total of ten haplotypes (six in T. tennesseensis and four in T. jonesi) that were present either in individual caves or in geographically nearby caves. Our results are consistent with previous morphology-based species definitions showing T. tennesseensis and T. jonesi belonging to distinct taxa. They also indicate that gene flow is limited between caves since the majority of haplotypes are restricted to a single cave. Our research contributes to the growing body of phylogeographic information about cave species from the Cumberland Plateau, and provides a point of comparison for future studies on millipedes.