Genetic differentiation despite teleplanic larval dispersal: Allozyme variation in sipunculans of the Apionsoma misakianum species-complex

We examined the genetic evidence for dispersal in the sipunculan Apionsoma misakianum (Ikeda 1904) by analysis of allozymes (using a total of nine pol ymorphic loci) in larval and adult samples. Genotypes of adults reared from late-stage larvae collected from the Florida Current were compared with ge notypes of adults from three locations: eastern central Florida, the Florid a Keys and the Bahamas. Genetic differences were found between individuals from the southern localities and the majority of specimens from the norther n locality. The multilocus genotypes of the specimens reared from larvae of the Florida Current were characteristic of specimens from the Florida Keys and the Bahamas. Despite evidence for larval influx northward into the cen tral-Florida area via the Florida Current, the southern genotypes were pres ent in only a few adults collected (4.5%) at a northern site, with no indic ation of "hybrids" occurring between northern and southern genotype based o n allozymes (i.e., heterozygotes). Furthermore, genetic separation of the n orthern and southern genotypes coincides with a faunal boundary noted for o ther species.