Molecular and Morphological Evidence for a Novel Black Bass Species Native to Rivers of the East Gulf Coastal Plain

While investigating hybridization in shoal bass Micropterus cataractae in the Chipola River, Florida, we encountered a distinctive genetic signature from an unknown taxon.  We soon pinpointed the signature’s source to a novel form of bass inhabiting the rivers of the East Gulf Coastal Plain.  Superficially, these bass resemble spotted bass M. punctulatus and have mistakenly been considered as such.  Genetically, they can be diagnosed by four autapomorphies at two nuclear gene introns and one mtDNA gene and by various clustering techniques using 17 microsatellite loci.  In nuclear-gene phylogenies based on 10 sequenced introns, this reciprocally monophyletic taxon shares a common ancestor with spotted bass and Guadalupe bass M. treculii; remaining micropterids are more distantly related.  Morphologically, they differ from spotted bass, Alabama bass M. henshalli, 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 and its habitat preferences seem to be most similar to those of the Guadalupe bass.  Criteria for taxonomic recognition were satisfied for 13 of 18 operational species concepts and for the fundamental concept.  For those concepts in which criteria were not satisfied, analogous shortfalls occurred in all recognized micropterids.  We have recommended this endemic taxon be elevated to species rank, recognized by the common name ‘Choctaw bass’ and scientific name Micropterus haiaka – pronounced ‘high-ah-kah’ and translatable as “revealed” or “made manifest” in the Choctaw Native American language.  Populations of Choctaw bass, unrecognized, could be susceptible to negative ecological and genetic impacts and/or serve as vectors of similar damage to congeneric populations.