Hamistyelicola, Kim & Boxshall, 2021

Kim, Il-Hoi & Boxshall, Geoff A., 2021, Copepods (Cyclopoida) associated with ascidian hosts: Ascidicolidae, Buproridae, Botryllophilidae, and Enteropsidae, with descriptions of 84 new species, Zootaxa 1, pp. 1-286 : 24

Hamistyelicola gen. nov.

Diagnosis. Body slender; prosome-urosome division not distinct. Prosome 5-segmented. Urosome 6-segmented. Spinose pad present ventrally between pre-anal and anal somites. Caudal ramus bearing 6 setae. Rostrum not developed. Antennule 7-segmented. Antenna 3-segmented, bearing terminal claw; all segments armed. Mandible consisting of coxa with well-developed gnathobase bearing 4 major teeth on medial margin, and biramous palp, armed with 6 setae on endopod and 1 seta on tip of small exopod. Maxillule consisting of precoxa and biramous palp; precoxa bearing 7 to 9 setae on arthrite; palp bearing 5 setae on basis, 2 setae on exopod, and 6 setae on endopod; exopod and endopod articulated from or fused with basis. Maxilla 2- or 3-segmented; first segment (syncoxa) with single endite tipped with 3 setae; second segment (allobasis) or second and third segments (basis and endopod) bearing 8 or 9 setae in total, lacking claw. Maxilliped 1 or 2-segmented, armed with 4 or 5 setae. Legs 1-4 broad, biramous with 2-segmented rami; coxa unarmed; basis with large outer seta. Basis of leg 1 bearing inner distal spine. Spines on exopods and endopods distinct. Distal segment of exopod of legs 2-4 transformed to large, powerful hook. Leg 5 consisting of lamellate protopod bearing 1 seta distally and small exopod bearing 6 setae. Leg 6 represented by 3 dentiform processes on genital operculum.

Type species. eamẚstyelẚcçla lẚghtẚ (Illg & Dudley, 1980) comb. nov. (originally as Styelẚcçla lẚghtẚ), by original designation .

Other included species. eamẚstyelẚcçla mçnnẚçtçrum gen. et sp. nov.

Etymology. The name is derived from the Latin ham (=hooked) and the generic name Styelẚcçla. Gender masculine.

Remarks. The most outstanding feature of eamẚstyelẚcçla gen. nov. is the transformation of the second exopodal segment of legs 2-4 into a powerful hook. The discovery of a second species possessing this hook, as in Styelẚcçla lẚghtẚI leads us to establish a new genus to accommodate both these two species.

Within the family, eamẚctyelẚcçla gen. nov. appears closer to Ascẚdẚcçla than to Styelẚcçla as both genera share the following character states: the first endopodal segment of the antenna bears a seta, the maxilliped is armed with multiple setae, and the inner spine on the first endopodal segment is present at least in leg 4. The presence of the large conspicuous hook on the exopod of legs 2-4, and the possession of 2-segmented fifth leg are distinctive features separating the new genus from Ascẚdẚcçla.