Systematics of North Pacific sand lances of the genus Ammodytes based on molecular and morphological evidence, with the description of a new species from Japan

The systematic status of North Pacific sand lances (genus Ammodytes) was assessed from mitochondrial DNA (cytochrome oxidase c subunit 1) sequence data and morphological data to identify the number of species in the North Pacific Ocean and its fringing seas. Although only 2 species, Ammodytes hexapterus and A. personatus, have been considered valid in the region, haplotype networks and trees constructed with maximum parsimony and genetic distance (neighborjoining) methods revealed 4 highly divergent monophyletic clades that clearly represent 4 species of Ammodytes in the North Pacific region. On the basis of our material and comparisons with sequence data reported in online databases, A. personatus is found throughout the eastern North Pacific Ocean, Gulf of Alaska, Aleutian Islands, and the eastern Bering Sea where it co-occurs with a northwestern Arctic species, A. hexapterus, that is found throughout the North American Arctic from Hudson Bay, Canada, in the east, through the Beaufort and Chukchi seas, into the northern and western Bering Sea, and to the southern Sea of Okhotsk in the Soya Strait off Hokkaido, Japan. Two other species reside in waters around Japan: A. japonicus throughout the Sea of Japan and the Seto Inland Sea and a new species in the Sea of Japan and the North Pacific Ocean off northern Honshu. We designate neotypes for A. hexapterus and A. personatus because of the absence of type material and the close similarity of these 2 species. Ammodytes aleutensis is a junior synonym of A. japonicus, and A. alascanus is a junior synonym of A. personatus.