Genetic variation in the longear sunfish (Lepomis megalotis)

Abstract

The systematics and zoogeography of the longear sunfish (Lepomis megalotis) are poorly understood. Relationships among geographic variants throughout the range of the species are unclear, and it is uncertain whether the northern longear sunfish, L. m. peltastes, should be classified as a separate species. We used protein electrophoresis to examine genetic variation among 22 longear sunfish populations and one dollar sunfish (Lepomis marginatus) population. Principal component analysis of allele frequency data could not separate the most morphologically distinct form, the northern longear sunfish, from the central long-ear sunfish, L. m. megalotis. Populations distributed from the Missouri River basin to the Colorado River in Texas, for which the subspecific names L. m. breviceps and L. m. aquilensis are available, clustered as a distinct group. No evidence was found to suggest that a distinct form exists in the Ozark Highlands. Lepomis marginatus was genetically distinct from all L. megalotis populations, but most distinct from L. m. megalotis and L. m. peltastes. Protein electrophoresis should allow diagnosis of distribution limits and intergrade zones of southwestern forms, but a more sensitive technique is required to separate L. m. megalotis and L. m. peltastes.