A tale of two soft-shell clams: an integrative taxonomic analysis confirms Mya japonica as a valid species distinct from Mya arenaria (Bivalvia: Myidae)

摘要: The soft-shell clam Mya arenaria Linnaeus, 1758 is a commercially important fishery resource that occurs in boreal and temperate environments the Northern Hemisphere. Whether single species with circumboreal range or complex also comprising japonica Jay, 1857 distributed north Pacific has long been debated by malacologists palaeontologists based on slight differences shell morphology. We used an integrative taxonomic approach incorporating available spp. mitochondrial COI 16S rRNA, nuclear 28S rRNA gene sequences, as well spermatozoan morphological characters to test validity of M. examine distribution. Although morphology were minor, results from tree topologies, pairwise uncorrected p-distances, Automatic Barcode Gap Discovery (ABGD) ultramorphological data confirm both its endemic region northwest Pacific, here newly reported introduced populations British Columbia northeast show North Atlantic, Barents Sea (Arctic Ocean) Mediterranean. estimate these two closely related sister diverged 4.1-12.5 Myr during early Pliocene late Miocene, which consistent current evolutionary theory regarding arenaria. In addition, ABGD indicated congener truncata may represent complex, but additional evidence still needed clarify status.