(restricted synonymy and bibliography)
Leptognathia G.O. Sars, 1882: 40 –41.
Cryptocope G.O. Sars, 1882 (partim): Kudinova-Pasternak, 1982: 155 –156. Tanais Latreille, 1831 (partim): Lilljeborg, 1864: 21. Type species: Tanais breviremis Lilljeborg, 1864.
Species included (Japanese waters, Kurile-Kamchatka Trench and Japan Trench species in bold): L. aneristus n.sp., L. bamberi, L. breviremis, NE Atlantic; L. breviremoides Sieg, 1986 a, Antarctica; L. glandiceps Shiino, 1978, Kerguelen Islands, 60 metres; L. gyreae Larsen, 2005, Gulf of Mexico, 675–677 metres; L. longa (Kudinova-Pasternak, 1982), Mediterranean Sea, 2890 metres; L. manca G.O. Sars, 1882, NE Atlantic; L. vitjazi (Kudinova-Pasternak, 1982), Mediterranean Sea, 1320 metres.
Diagnosis (after Larsen & Shimomura 2007) Female/neuter. Leptognathiid with cheliped fixed finger and dactylus simple. Uropod exopod one-articled.
Remarks. Leptognathia has suffered both the greatest accretion and, latterly, attrition of all tanaidomorphan genera as species have been added to it or removed in subsequent revisions (e.g. Hansen 1913; Lang 1968; Bird & Holdich 1984; Sieg 1986 a; and Larsen & Shimomura 2007). Further revision and contraction is anticipated.