Aspidophoroides monopterygius (Bloch, 1786) .

Alligatorfish. To 22 cm (8.7 in) TL (Mecklenburg et al. 2016). Atlantic and Pacific Oceans; Seas of Japan and Okhotsk to Gulf of Anadyr, to Bering Sea, and Aleutian Islands, to Chukchi Sea, and Beaufort Sea eastward (to about 71°20’N, 151°06’W), and to Prince William Sound, Gulf of Alaska (Mecklenburg et al. 2016). Benthic; depth: 8–340 m (26–1,115 ft) (min.: Mecklenburg et al. 2002; max.: Mecklenburg et al. 2018). A maximum depth of 500 m (1,640 ft) reported in Mecklenburg et al. (2002) cannot be verified and a record of 695 m (2,280 ft) (Coad in Coad and Reist 2018) is without documentation. While we consider Aspidophorides bartoni Gilbert, 1896 to be a junior synonym (Mecklenburg et al. 2018), some authors consider it a valid species (e.g., Tohkairin et al. 2015).