VERIFICATION OF THE SPECIFIC STATUS OF THE ENDANGERED ANTHONYS RIVER SNAIL, ATHEARNIA-ANTHONYI, USING ALLOZYME ELECTROPHORESIS

Although nominally the single surviving representative of a unique ple urocerid taxon, Athearnia anthonyi (Budd, in Redfield, 1854) is so rar ely collected that even its specific status has been uncertain. We use d allozyme electrophoresis to compare a population of A. anthonyi to t he similar pleurocerid snail, Leptoxis praerosa (Say, 1821), co-occurr ing with it in the Sequatchie River of Tennessee, and to a second popu lation of L. praerosa collected approximately 500 km distant. Observed levels of heterozygosity offered no evidence of inbreeding or unusual ly severe population bottlenecking in any of these populations. Striki ngly different allele frequencies at five of the eleven enzyme loci ex amined, together with differences in shell morphology especially appar ent in young individuals, confirmed that A. anthonyi and L. praerosa a re distinct species. Their similarity at the six loci remaining suppor ts previous suggestions that Athearnia may be a subgenus of Leptoxis.