Ischiomysis Wittmann, 2013

Wittmann, Karl J. & Wirtz, Peter, 2024, An update on the genus Ischiomysis with a description of I. proincisa sp. nov. (Crustacea, Mysida) from a sublittoral marine cave in the Gulf of Guinea (tropical E-Atlantic), Zoosystematics and Evolution 100 (4), pp. 1431-1442 : 1431-1442

Genus Ischiomysis Wittmann, 2013

Ischiomysis Wittmann, 2013: 489–492; San Vicente and Monniot 2014: 333, 340; Wittmann et al. 2014: 231, 309, 341; Wittmann and Wirtz 2017: 147; Daneliya 2021: 3, 6–7; Mees and Meland 2024: AphiaID 723169.

Short diagnosis.

Shortened and updated from Wittmann (2013). Heteromysini with normal eyes, eyestalks without spiniform extension, no ocular papilla. Flagellate spine opposed by a large smooth seta on disto-mesial corner of terminal segment of antennular trunk; no modified spines (setae) on basal and middle segments. Appendix masculina short, with tuft of setae. Antennal scale well developed, with apical segment. Carapace (not counting rostrum) and mouthparts are normal. Thoracic sternites 2–8 without median processes in both sexes. Endopods 1–8 with distinct claw at apex. Third endopod specialized as gnathopod by forming a moderately strong subchela; carpus enlarged, not subdivided, armed with several flagellate spines. Fourth endopod with several weakly modified setae on carpopropodus and with apically bifid claw in both sexes. Endopod 8 only in males with a strong spiniform extension of praeischium and with 1–2 modified flagellate spine on ischium. Pleopods entire, reduced to small setose plates in both sexes; no spines or teeth. Uropods normal, with setae all around, no spine. Telson with spines on lateral margins; distinct apical cleft with spine-like laminae, no setae.

Species inventory.

I. peterwirtzi Wittmann, 2013 , from sublittoral rock recesses up to large marine caves, mostly observed associated with the club-tipped anemone Telmatactis cricoides but also distant from anemones at São Vicente Island and the small nearby island Ilhéu dos Pássaros in the Cape Verde archipelago, tropical E-Atlantic.

I. telmatactiphila Wittmann, 2013 , close to T. cricoides in well-lit rock recesses at São Tomé Island and the small nearby islet Ilhéu de Santana, Gulf of Guinea, tropical E-Atlantic.

I. proincisa sp. nov. from a large semi-dark sublittoral cave at the coast of Rolas Island, close to São Tomé Island, in the Gulf of Guinea, tropical E-Atlantic.