Reevaluation of the Lythrurus ardens (Cypriniformes: Cyprinidae) Complex with Recognition of Three Evolutionary Species

Abstract

Samples were taken from throughout the range of the three nominal taxa that comprise the Lythrurus ardens species-complex: L. fasciolaris (Ohio basin and Black Warrior River system, Alabama), L. ardens (York, Roanoke, James, and upper New River drainages), and L. matutinus (Tar and Neuse River drainages, North Carolina). Based on breeding tubercle patterns, color of nuptial males, anal-fin ray number, and general body shape, the three taxa were diagnosed and recognized as species. Lythrurusfasciolaris has a mode of 10 anal rays, and nuptial males have a keeled nape, deep body, several blue-gray bars on the dorsum, and intense red or orange on the fins but not on top of the head. Lythrurus matutinus has a mode of 11 anal rays and is slender bodied; nuptial males have blood-red on top of the head, no red in the paired fins, and no blue-gray bars on the dorsum; nuptial females are masculinized, with extensive tubercle development on the head. Lythrurus ardens has a mode of 11 anal rays and is moderately slender bodied; nuptial males have faint red in the fins and on top of the head, faint blue-gray bars on the dorsum, and blue on the side; females are not masculinized. Fourteen of 29 presumptive gene loci examined were polyallelic. Allelic and genotypic variation of three loci (Est-2, Pgm-A, Est-3) support genetic isolation of the western species, L. fasciolaris, from the two eastern species, L. ardens and L. matutinus. The magnitude of allozymic differentiation between eastern and western species is similar to differences reported for other species of the genus Lythrurus. The three taxa represent three evolutionary species. Evidence for lineage independence among the three species includes an array of intrinsic characters with independent corroboration from extrinsic biogeographic evidence. Recognition of L. fasciolaris and L. matutinus as species brings the total