Onisimus Boeck 1871
Creators: name: Lowry, J. K.
name: Kilgallen, N. M.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Uristidae
Onisimus

description: Onisimus Boeck, 1871
(Fig. 27)
Onisimus Boeck, 1871: 111.— Stebbing 1906: 25.—Schellenberg 1927: 659.— Stephensen 1929: 53.— Gurjanova 1951: 161.—J.L. Barnard 1969: 352.— Barnard & Karaman 1991: 506.— Lowry & Stoddart, 1993: 168.—Vader, Johnsen & Berge, 2005: 2.
Onesimus Boeck, 1876: 161 (invalid emendationof Onisimus Boeck, 1871).—G.O. Sars 1891: 104.
Pseudalibrotus Della Valle, 1893: 798.— Stebbing 1906.—33.—Schellenberg 1927: 671.— Stephensen 1929: 55 (type species: Anonyx litoralis Boeck, 1871, monotypy).
Alibrotus Sars, 1891: 101.
Paronesimus Stebbing, 1894: 14.— Stebbing 1906: 43.— Gurjanova 1951: 196.— Barnard 1969: 357.— Barnard & Karaman 1991: 516 (type species: Paronesimus barentsi Stebbing, 1894, monotypy).
Boeckosimus J.L. Barnard, 1969: 330.— Barnard & Karaman 1991: 470 (type species: Anonyx edwardsii Krøyer, 1846, original designation).
Type species. Anonyx litoralis Krøyer, 1845, selected by Boeck, 1876.
Included species. Onisimus includes 26 species: O. abyssi Oldevig, 1959; O. affinis Hansen, 1887; O. barentsi (Stebbing, 1894); O. birulai (Gurjanova, 1929b); O. botkini Birula,1897; O. brevicaudatus Hansen, 1887; O. caspius (G.O. Sars, 1896); O. caricus Hansen, 1887; O. derjugini (Gurjanova, 1929a); O. dubius Schellenberg, 1935 b; O. edwardsii Krøyer, 1846; O. glacialis (G.O. Sars, 1900); O. krassini Gurjanova, 1951); O. leucopis G.O. Sars, 1879; O. litoralis (Krøyer, 1845); O. nanseni (G.O. Sars, 1900); O. normani G.O. Sars, 1891; O. platyceras (G.O. Sars, 1896); O. plautus Krøyer, 1845; O. punctatus (Bate, 1862); O. sextonae Chevreux, 1926; O. sibiricus Brüggen, 1909; O. simus Gurjanova, 1962; O. turgidus G.O. Sars, 1879; O. uschakovi (Gurjanova, 1933); O. zenkevitchi Mednikov, 1960.
Nomina nuda. Onisimus abyssicola (Stuxberg, 1880); O. crassini (Gorbunov, 1946); O. vorax (Stuxberg, 1880); O. zebra (Stuxberg, 1880).
Diagnostic description. Antenna 1 peduncle article 1 without anterodistal lobe; accessory flagellum forming cap covering callynophore. Antenna 2 without brush setae. Mandible molar a column with fully triturating surface. Maxilla 1 outer plate a well developed 7/4 crown. Maxilla 2 inner plate significantly shorter than outer plate. Gnathopod 1 subchelate; coxa 1 large, about as long as coxa 2, subrectangular with concave anterior margin; ischium short (length less than 2 × breadth); carpus short (length 1 to 2 × breadth); propodus margins slightly tapering distally. Uropod 2 inner ramus with or without constriction. Telson entire to moderately cleft.
Remarks. Based on the morphology of gnathopod 1 Onisimus and Anonyx are very similar. Onisimus retains the triturating molar characteristic of tryphosine amphipods while Anonyx has a derived setose tongue.
description: Published as part of Lowry, J. K. & Kilgallen, N. M., 2014, A generic review of the lysianassoid family Uristidae and descriptions of new taxa from Australian waters (Crustacea, Amphipoda, Uristidae), pp. 1-92 in Zootaxa 3867 (1) on page 45, DOI: 10.11646/zootaxa.3867.1.1, http://zenodo.org/record/5585734