Genetic identification and phylogeny of the unionid genera, Lampsilis and Elliptio of the south east Atlantic slope

Approximately 70% of freshwater mussel species in North America are considered extinct, endangered, or threatened, and a large number of these are endemic to a narrow geographic range. Freshwater mussel conservation efforts have been limited by taxo-nomic ambiguities and morphologic convergence. Lake Wacca-maw in southeastern North Carolina contains two described endemic species, Lampsilis fullerkati and Elliptio waccamawensis, which conchologically are nearly identical, complicating conservation efforts. To help alleviate this problem, a Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) assay was developed for genetic identification. Genomic DNA was obtained using a non-lethal method of hemolymph extraction. Two diagnostic RFLPs were used to type 112 individuals. RFLP and sequencing data showed that three individuals were misidentified based on morphology. In addition, phylogenetic analysis was used to assess the taxonomic status of these putative endemics. 16s ribosomal DNA sequences were obtained from 140 individuals from both genera, sampled from Lake Waccamaw, the adjacent Waccamaw River, and the Yadkin/Pee Dee and Lumber Rivers in the Pee Dee Drainage. Results from neighbor-joining and maximum likelihood trees suggest the endemic status of both L. fullerkati and E. waccamawensis may need to be reconsidered. Lampsilis fullerkati individuals fall in a large clade containing Lampsilis radiata radiata from outside the lake, and the endemic is not a distinct phylogroup. Additional, faster-evolving gene regions and type specimens are being sequenced to evaluate this result. A similar approach is being used for E. waccamawensis, which appears phylogenetically indistinguishable from Elliptio collected outside of the Lake.