Black Bass Diversity: Multidisciplinary Science for Conservation

<em>Abstract</em>.—While investigating hybridization in Shoal Bass <em>Micropterus cataractae</em> in the Chipola River, Florida, we encountered a distinctive genetic signature from an unknown taxon. We soon determined that the signature originated from a novel bass that inhabits Gulf Coastal Plain rivers and streams in Florida. Superficially, these bass resemble Spotted Bass <em>M. punctulatus</em> and historically have been considered as such. Cladistically, they are diagnosable through four autapomorphies at two nuclear gene introns and one mitochondrial DNA gene; phenetically, by various clustering techniques using 17 microsatellite loci. In nuclear-gene phylogenies based on 10 sequenced introns, this taxon is reciprocally monophyletic and shares a common ancestor with a clade comprising Spotted Bass and Guadalupe Bass <em>M. treculii</em>. Morphologically, its members differ from Spotted Bass, Alabama Bass <em>M. henshalli</em>, and Guadalupe Bass in mean/modal counts of soft anal-fin and dorsal-fin rays. They further appear to differ from Guadalupe Bass in mean/modal counts of scales above and below the lateral line and around the caudal peduncle. Little is known yet about the biology and life history of this new taxon. It appears to occupy different mesohabitats than those occupied by sympatric congeners, although its habitat preferences seem to be most similar to those of the Guadalupe Bass. Operational requirements were satisfied for 11 of 15 applicable species concepts, providing a foundation for taxonomic recognition under the fundamental evolutionary species concept. For operational concepts in which requirements were not satisfied, analogous shortfalls occur in all recognized micropterids. We therefore recommend that this taxon, designated herein as the Choctaw Bass, be elevated to species rank. Undetected, native populations of Choctaw Bass could be susceptible to negative ecological and genetic impacts and/or serve as vectors of similar damage to congeneric populations.