Elassoma gilberti, a New Species of Pygmy Sunfish (Elassomatidae) from Florida and Georgia

Abstract

A new species of pygmy sunfish, Elassoma gilberti (Elassomatidae), is described from northwestern Florida and extreme southwestern Georgia. It previously has been confused with its sister species, Elassoma okefenokee Böhlke 1956. The two are very similar morphologically, but differ in the number of preopercular canal pores (four in E. gilberti, three in E. okefenokee), in average number of anal fin rays (usually seven in E. gilberti, usually eight in E. okefenokee), and in more subtle differences in coloration, body depth, and dorsal and anal fin size. The distinction of the two species is supported by eight fixed differences at the mitochondrial 16S rRNA locus and 12 fixed differences at the nuclear S7 locus. Phylogenetic analyses using these molecular characters supported monophyletic clades that contained haplotypes and alleles found uniquely in the two taxa. Elassoma gilberti is found in stream systems draining into the Gulf of Mexico from Choctawhatchee Bay in the Florida panhandle south to the Withlacoochee and Homosassa drainages in west-central Florida. Both species occur in the Suwannee River drainage, E. gilberti in the lower and middle sections and E. okefenokee in the middle and upper sections. They remain genetically distinct where sampled in this drainage but have not been found syntopically.

The history and nomenclatural status of the name Elassoma evergladei orlandicum Lönnberg 1894 is discussed and a lectotype is designated based on the earlier findings of R. M. Bailey and J. E. Böhlke. Lectotype designation relegates the name to the synonymy of Elassoma evergladei Jordan 1884.