Ichnopus Costa 1853

(Fig. 18)

Ichnopus Costa 1853: 169 .— Costa, 1857: 188.— Boeck, 1871: 98.— Sars, 1890: 39.— Della Valle, 1893: 800 (in part).— Stebbing, 1906: 52.— Chevreux & Fage, 1925: 46.— Stephensen, 1929: 60.— Pirlot, 1936: 269.— Gurjanova, 1951: 219.—J.L. Barnard, 1969: 346.— Lincoln, 1979: 94.— Ledoyer, 1986: 760.— Diviacco & Ruffo, 1989. 486— Barnard & Karaman, 1991: 491.— Lowry & Stoddart, 1992: 191 (key).— Lowry & Stoddart, 2003: 282 (catalogue).

Glycera Haswell, 1879: 256 (homonym Polychaeta) (type species, Glycera tenuicornis Haswell, 1879, monotypy.

Glycerina Haswell, 1882: 256 (new name for Glycera Haswell, 1879).— Stebbing, 1906: 60.— Pirlot, 1936: 270.—J.L. Barnard, 1969: 345.— Barnard & Karaman, 1991: 488.

Type species. Ichnopus taurus Costa, 1853, monotypy .

Included species. Ichnopus includes 18 species: I. annasona Lowry & Stoddart, 1992; I. capricornis Lowry & Stoddart, 1992; I. caritus Lowry & Stoddart, 1992; I. comorensis Lowry & Stoddart, 1992; I. cribensis Lowry & Stoddart, 1992; I. macrobetomma Stebbing, 1917; I. malpatun Lowry & Stoddart, 1992; I. parriwi Lowry & Stoddart, 1992; I. pelagicus Schellenberg, 1926a; I. pseudoserricrus Ledoyer, 1986; I. serricrus Walker, 1909; I. spinicornis Boeck, 1861; I. taurus Costa, 1853; I. tenuicornis (Haswell, 1879 a); I. teretis (Andres, 1981); I. walkeri G. Vinogradov, 2004; I. wardi Lowry & Stoddart, 1992; I. woodmasoni (Giles, 1890) .

Diagnostic description. Antenna 1 peduncle article 1 without anterodistal lobe; accessory flagellum not forming cap covering callynophore. Antenna 2 with brush setae. Mandible molar setose with variously reduced triturating surface. Maxilla 1 outer plate a well developed 7/4 crown. Maxilla 2 inner plate slightly shorter than outer plate. Gnathopod 1 simple; coxa 1 large, subrectangular with concave anterior margin; ischium long (length 2 × to 4 × breadth); carpus long (length 2 to 4 × breadth) to very long; propodus margins subparallel; dactylus with complex spination on posterior margin. Uropod 2 inner ramus constricted. Telson moderately to deeply cleft.

Remarks. Based on the simple first gnathopods, with a long ischium and long to very long carpus and a dactylus with complex spination, Ichnopus is most similar to Eclecticus and Nagada . Ichnopus differs from both genera in having a deep to moderately cleft telson.

Distribution. Temperate/tropical cosmopolitan.