Ischnomesus Richardson, 1908

Souza-Filho, Jesser F., 2017, Three new species of the genus Ischnomesus (Isopoda: Asellota: Ischnomesidae) from Brazilian deep sea, Zootaxa 4312 (2), pp. 259-276 : 261-262

Ischnomesus Richardson, 1908

Ischnosoma G.O. Sars, 1868: 84 .

Ischnomesus Richardson, 1908: 81 ;— Hansen, 1916: 56;— Gurjanova, 1932: 40 l;— Wolff, 1956: 88;— Menzies, 1962: 111;— Wolff, 1962: 73;— Menzies & George, 1972: 971;— Kussakin, 1988: 419;— Merrin & Poore, 2003: 290 ;— Kavanagh et al., 2015: 203 .

Rhabdomesus Richardson, 1908: 81 .

Bactromesus Wolff, 1962: 83 .

Type species: Ischnosoma bispinosum G.O. Sars, 1868 (by monotypy).

Diagnosis. See Kavanagh et al. (2015).

Species included: Ischnomesus anacanthus Wolff, 1962 ; I. andriashevi Birstein, 1960 ; I. antarcticus Schultz, 1979 ; I. armatus Hansen, 1916 ; I. bacilloides ( Beddard, 1886) ; I. bacillopsis ( Barnard, 1920) ; I. bacillus ( Beddard, 1886) ; I. bidens Menzies, 1962 ; I. birsteini Wolff, 1962 ; I. bispinosus ( G.O. Sars, 1868) ; I. bruuni Wolff, 1956 ; I. calcificus Menzies & George, 1972 ; I. caribbicus Menzies, 1962 ; I. carolinae Chardy, 1974 ; I. chardyi Kussakin, 1988 ; I. decemspinosus Menzies, 1962 ; I. elegans Menzies, 1962 ; I. elongatus Birstein, 1963 ; I. fragilis Birstein, 1971 ; I. glabra Kensley, 1984 ; I. gracilis ( Birstein, 1960) ; I. harrietae Kavanagh, Frutos & Sorbe, 2015 ; I. justi Merrin & Poore, 2003 ; I. kussakini nom. nov. (Kussakin, 1982); I. latimanus Birstein, 1971 ; I. magnificus Menzies, 1962 ; I. multispinis Menzies, 1962 ; I. norvegicus Svavarsson, 1984 ; I. paucispinis Menzies, 1962 ; I. planus Wolff, 1962 ; I. profundus Hansen, 1916 ; I. roseus Wolff, 1962 ; I. simplex Menzies & George, 1972 ; I. simplissimus Menzies, 1962 ; I. spaercki Wolff, 1956 ; I. tasmanensis Merrin & Poore, 2003 ; I. vinogradovi Birstein, 1963 and I. wolffi Menzies, 1962 .

Remarks. According to Kavanagh et al. (2015), the freely articulating posterior pereonites, pleonite 1 and pleotelson observed in Ischnomesus is a condition presumed to be plesiomorphic, with other genera showing various degrees of fusion of the pereonites (e.g. pereonites 5–7, pleonite and pleotelson fused together in genus Haplomesus ; Kavanagh & Wilson 2007). Uniarticulate uropods have been described by Merrin & Poore (2003) for Ischnomesus justi , so the biarticulate uropods may not be a diagnostic character for the genus, although all other species, described with this structure, have biarticulate uropods.