Key to species of Allocareproctus

1A. Teeth trilobed, nearly all with moderate to strong lateral lobes; peritoneum pale or dark; nasal papilla present and unpigmented or absent................................................. 2

1B. Teeth simple, often with weak shoulders; peritoneum dark; nasal papilla present, pigmented ...................................................................................................................... 4 2A. Peritoneum pale; nasal papilla absent; interorbital papilla absent; Aleutian Islands: Kiska Island to the Islands of Four Mountains ................... Allocareproctus tanix n. sp. 2B. Peritoneum dark; nasal papilla present or absent; interorbital papilla present or absent ....................................................................................................................................... 3 3A. Nasal papilla absent; anal­fin rays 36–39; interorbital papilla present; papillae on maxillary pores 5–6 or 6 only; Aleutian Islands: Buldir Island to the Islands of Four Mountains ............................................................. Allocareproctus unangas n. sp. 3B. Nasal papilla present; anal­fin rays 33–35; interorbital papilla present or absent; papillae on maxillary pores 4–6 or more; Aleutian Islands: Seguam Island to the Islands of Four Mountains ................................................................. Allocareproctus ungak n. sp. 4A. Orobuccal cavity dark; orobuccal valve with 4–6 finger­like projections; gill rakers 14–18; abdominal vertebrae 12; anterior part of body dark; interorbital papilla absent; Aleutian Islands: Seguam Island to the Islands of Four Mountains................................ ........................................................................................ Allocareproctus kallaion n. sp. 4B. Orobuccal cavity pale; orobuccal valve with 1 finger­like projection; gill rakers 8–12; abdominal vertebrae 10–12; anterior part of body pale; interorbital papilla present or absent; Aleutian, Pribilof, and Kuril Islands; Japan ..... Allocareproctus jordani (Burke)