Prodoroixys Kim & Boxshall 2020, gen. nov.

Prodoroixys gen. nov.

Diagnosis. Body form as in Doroixys, stout, moderately inflated. Dorsal cephalic shield with or without posterolateralhorn-likeprocesses.Metasomeunsegmented or indistinctly segmented; fifth pedigeroussomite fused with fourth. Freeurosome 5-segmented. Caudalramus with 6 setae. Rostrum well-developed. Antennule 9- segmented; first segment armed with 2 setae. Antenna 4-segmented with 2-segmented endopod. Mandible with broadened medial margin of coxal gnathobase bearing 5 or 6 teeth; exopodwith 5 setae; endopodwith 1 seta on first segment and 5 to 7 setae on second. Maxillule with 9 or 10 setae on arthrite, 1 each on coxal endite and epipodite, 2 on basis, 4 onexopodand 3 on endopod. Maxilla 5-segmented; syncoxawith 3, 1, 2, and 3 setae on first to fourth endites, respectively; basis with claw plus 2 setae; endopod 3-segmentedwith 1, 1, and 3 (or 4) setae on first to third segments, respectively. Maxilliped unsegmented, armed with more than 6 setae. Legs 1–3 with 3-segmented rami. Leg 4 with 3-segmented exopod and 2- or 3-segmented endopod. Leg 1 basiswith inner distal spine. First and second segments of exopod and endopod of legs 1 and 2 with inner setae. First endopodal segment of leg 3 also with inner seta. Leg 5 rudimentary.

Type species. Prodoroixys antarctica gen. et sp. nov. by original designation.

Other included species. Prodoroixys bathybia gen. etsp. nov.

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Etymology. The name of the new genus is derived from pro (=”before” in Greek) andthegenericname Doroixys, and alludes to the relatively primitive character states exhibited by the new genus in comparison with Doroixys. Gender feminine.

Remarks. The new genus is readily separated from Doroixys and Loboixys by the more plesiomorphic state of the armature of the oral appendages. It has 2 setae on the basis of themaxillule (only 1 in Doroixys and Loboixys), a 3-segmented endopod on the maxilla (2-segmented in Doroixys and 1- or 2-segmented in Loboixys), and an inner seta on the first and second segments of the 3-segmented exopods of legs 1 and 2 (seta missing from at least some of these segments). The new genus is similar to Notoixys gen. nov. (see below) in the degree of complexity of the armature of oral appendages, but can be distinguished from the latter genus by the broad cutting margin of the mandibular coxa (vs. narrow in Notoixys gen. nov.), by the presence of a seta-tipped coxal endite of the maxillule (vs. lacking in Notoixys gen. nov.), and only 2 setae on the maxilliped (vs. 3 or more in Notoixys gen. nov.).