Meeting Abstract
The state of Alabama is among the most specious in regards to aquatic fauna. However, much of this biodiversity remains unexplored, particularly from a population genetics perspective. Here, 30 locations across the Middle, Upper, and Little Tallapoosa drainages in eastern Alabama were surveyed and sampled for populations of two native crayfish species, Cambarus englishi and C. halli. Using mitochondrial cytochrome oxidase subunit I (COI) sequencing, genetic structure was quantified and surprising ecological and evolutionary associations were identified. Specifically, C. englishi exhibited lower genetic diversity than C. halli, suggesting the two species have experienced differing evolutionary histories across the Tallapoosa River Basin. Along with this, both species possessed highly divergent mitochondrial COI haplotypes, implying that C. englishi and C. halli may each represent multiple genetic “species” belonging to single, respective morphological “species”. Unexpectedly, individuals of the two “species” from populations in the same geographic region typically belonged to a common genetic/haplotype network (i.e., C. englishi and C. halli from the Middle Tallapoosa are more closely related to each other than either is to members of the same “species” in other drainages). The importance of geography in the context of the population structure of C. englishi and C. halli was further supported by the fact that 45 of 46 total pairwise comparisons across the two “species” approached the upper limit of 1.0, meaning the sharing of haplotypes across populations was non-existent. Due to the exceptional endemism of these two “species”, streams inhabited by C. halli or C. englishi should be considered for conservation efforts in Alabama.
