Molecular and Morphological Evidence for Multiple Cryptic Crayfish Invasions in the Southern Appalachian Mountains

The crayfish genus Orconectes is widespread in North America and most diverse in the southeastern river drainages. Orconectes includes numerous drainage or regional endemics as well as several species considered to be aggressive invaders of freshwater ecosystems. During the last decade, the invasive O. rusticus was reported from three western North Carolina and eastern Tennessee streams. I used mtDNA and morphological analyses to examine species boundaries in Orconectes populations in the southern Appalachian Mountains and assess the validity of morphological diagnoses of invasive populations. I sequenced and analyzed a portion of the cytochrome c oxidase subunit I (COI) gene and compared data with individuals collected from O. rusticus’ native range in Kentucky as well as from GenBank specimen reference sequences. I evaluated the ability of dichotomous keys and quantitative morphological analyses to correctly classify specimens. Comparisons with reference sequences revealed a high level of cryptic diversity among populations. Furthermore, my data demonstrates the incongruence between using molecular data and morphological identifications for some crayfish taxa.