Mothocya, Costa

Ravichandran, S., Vigneshwaran, P. & Rameshkumar, G., 2019, A taxonomic review of the fish parasitic isopod family Cymothoidae Leach, 1818 (Crustacea: Isopoda: Cymothooidea) of India, Zootaxa 4622 (1), pp. 1-99 : 35-36

Genus Mothocya Costa, in Hope, 1851

Mothocya Costa, in Hope, 1851: 48.— Trilles, 1968: 168.— Monod, 1971: 174.— Bruce, 1986: 1092–1095.— Trilles, 1994: 174.— Hadfield, Sikkel & Smit, 2014c; 111.— Hadfield, Bruce & Smit, 2015; 148.

Irona Schiöedte & Meinert, 1884: 381 .—Stebbing, 1905: 27.— Richardson, 1905: 265.— Hale, 1926: 281.— Monod, 1971: 174.— Kussakin, 1979: 307.— Trilles, 1994: 166.

Type species. Mothocya epimerica Costa, in Hope , 1851; by subsequent designation ( Bruce 1986).

Diagnosis. Bruce (1986) was provided detail diagnosis for this genus and more recently, Hadfield et al. (2014b) given the revised diagnosis of this genus.

Remarks. Mothocya can be identified by the body not vaulted, widest at pereonite 5; cephalon with rostrum folded back, anterior margin rounded; antenna widely separated, antennula longer than antenna; eyes distinct; maxilliped article 3 with 3–5 recurved spines, without oostegite lobe; pereonite 1 antero-lateral angles slightly extended around cephalon; pleon subequal to pereon; pleonite 1 width largely concealed by pereonite 7; coxae 5–7 dorsally visible, project past the somite, big and rounded, reniform; brood pouch from coxae 2–4 and 6; uropod rami extend past the posterior margin of pleotelson, rami exopod longer than endopod. Males are smaller and not twisted, with appendix masculina on pleopod 2.

Bruce (1986) synonymised Irona with Mothocya , with many of the Irona species proving to be junior synonyms for known Mothocya species. The validity of the genus Irona was considered uncertain for many years (Monod 1923, 1971; Trilles 1968) after Schiöedte & Meinert (1884) described it as well as redescribing Mothocya in the same article.

Mothocya is most similar to Elthusa Schiöedte & Meinert, 1884 is and can be distinguished from that gneus by the antennula being longerr than the antenna, maxilliped article 3 without setae, and the pereopod dactyli are more robust and longer ( Bruce 1990). Female Mothocya is often twisted to one side due to the confines of the gill chamber. This Indian Mothocya is commonly found parasitizing the gill chambers of the host from the family Hemiramphidae and Belonidae ( Bruce 1986) . Mothocya occurs in all oceans and is predominantly tropical and subtropical in its distribution. Currently, 31 valid species has present in genus Mothocya ( Hadfield et al. 2017a) .