Loboixys Ooishi, 2006

Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), Megataxa 4 (1), pp. 1-6 : 527-528

Genus Loboixys Ooishi, 2006

Diagnosis. Body inflated, typically globular. Dorsal cephalic shield with horn-like processes present or absent. Brood pouch comprising second to fourth pedigerous somites, or fourth pedigeroussomite alone. Freeurosome typically 5-segmented, occasionally 4-segmented. Caudal ramus small, armed with up to 5 setae; caudal setae small, when present. Rostrum present. Antennule at most 7-segmented, occasionally unsegmented. Antenna 3-segmented, consistingof short coxa, basis, and unsegmented endopod bearing small terminal claw. Labrum weak. Mandible bearing 5 or 6 teeth on coxal gnathobase; palparmedwith 1 setaon basis, 5 on exopod, and 1 and 4 on first and second endopodal segments, respectively. Maxillulewith 6 to 10 setaeon arthrite, 1 on basis, 4 on exopod and 3 on endopod; coxal endite absent; epipodite (and its seta) present or absent. Maxilla 3- or 4-segmented, consistingof syncoxa, basis, and 1- or 2-segmented endopod; syncoxawith 3 endites; endopod with 4 setae in total (2 thick). Maxilliped as unsegmented lobe armed with 6 setae. Legs 1–4 each consisting of 2-segmented protopod and 2- or 3-segmented rami; segmentation of rami usually obscure. Inner coxal seta absent in legs 1–4. Second exopodal segment (or original second exopodal segment when not expressed) of leg 1 lacking outer element. First exopodal segment of legs 2–4 lacking inner seta. Proximal endopodal segment(s) of legs 2–4 with or without inner seta. Leg 5 rudimentary, bilobed or absent.

Type species. Loboixys ryukyuensis Ooishi, 2006 by original designation.

Other included species. Loboixys sibogae sp. nov., L. pilosa sp. nov., L. palauensis sp. nov., L. similis sp. nov., L. tetramera sp. nov., and L. capillosus (Ho & Kim 2006) comb. nov. (originally described as Doroixys capillosus ).

Remarks. Within the genus Loboixys we now recognize that there is a trend towards the segmentation of the rami of the swimming legs becoming obscured, and the leg setation tending to be reduced in all swimming legs. These trends stand in contrast to the characteristics of Prodoroixys gen. nov., Notoixys gen. nov., Borixys gen. nov., and Cystixys gen. nov., in each of which both rami of leg 1 are clearly 3-segmented and the first and second exopodal segments of leg 1 each bear outer and inner setal elements. In these new genera, the reduction of leg setation occurs mainly in the more posterior swimming legs. Thesecond exopodal segment (or original second exopodal segment in a 2-segmented exopod) of Loboixys characteristically lacks an outer element, as in Pentachaetus gen. nov. However, the latter genus is distinguishable from Loboixys by its possession of 5 large caudal setae and Doroixys -like leg setation.

Additional diagnostic features of Loboixys also appear to include: (1) the lack of an inner setaon the first exopodal segment of legs 2–4; (2) the horn-like processes on the dorsal cephalic shield are very small or absent; (3) the caudal ramus is short and the caudal setae are reduced in number and size, as in Notoixys gen. nov.; (4) the endopod of the mandibular palp is armed with 1 and 4 setae on the first and second segments, respectively; (5) the endopod of the maxilla is armed with a total of 4 setae; and (6) the maxilliped is armed with 6 setae. All known species of the Loboixys are associated with compound ascidians in the tropical Pacific.