Key for species of the genus Rhynchotalona

1. Rostrum short, 1.5 times or less longer than antennule.............................. R. weiri sp. nov. North America.

- Rostrum long, 2–3 times longer than antennule............................................................. 2.

2. Posteriormost ventral setae of valves long, their length exceeding the height of postabdomen, posteriormost setae being longest....................................................................... R. longiseta sp. nov. North America.

- Posterior ventral setae of valves short, their length much less than the height of postabdomen........................ 3

3. Basalmost large marginal denticle of postabdomen is located almost at postanal angle. Rostrum 2 times longer than antennule. Length less than 0.35 mm ................................................... R. kistarae Røen, 1973 . Greenland.

- Basalmost large marginal denticle of postabdomen is located at the middle of postanal margin. Rostrum 3 times longer than antennule. Length up to 0.6 mm ....................... R. falcata (Sars, 1862) . Europe, Kazakhstan, Siberia, Mongolia.