Sewelloya, Kim, 2014

Kim, Il-Hoi, 2014, Six new species of Copepoda (Clausiidae, Pseudanthessiidae, Polyankyliidae) associated with polychaetes from Korea, Journal of Species Research 3 (2), pp. 95-122 : 115-116

Sewelloya n. gen.

Diagnosis. Body cyclopiform. Cephalothorax with faint dorsal surture between cephalosome and first pedigerous somite. Urosome 5-segmented in female and 6-segmented in male. Caudal ramus with 6 setae. Rostrum obscure. Antennule 6-segmented, with 2, 6, and 7 setae respectively on first to third segments in female, but in male with 1 additional aesthetasc on second segment. Antenna 4-segmented and consisting of coxobasis and 3-segmented endopod; second endopodal segment with 1 claw and 2 setae, and distal endopodal segment with 3 claws and 4 setae. Labrum with clearly defined posterior lobes. Mandible short, strongly tapering, with 1 claw-like element on convex side and curved row of spinules on convex margin. Maxillule with 4 setae. Maxilla 2-segmented; distal segment with 2 setae and short, curved distal process bearing several dentiform spines on convex margin. Female maxilliped 3-segmented; first segment unarmed; middle segment with 2 setae; distal segment small and tapering with 2 small setae and spinulose apex. Male maxilliped 4-segmented; first and third segment without seta; second segment with 2 stout spiniform setae; terminal segment as large claw bearing 2 setae proximally. Legs 1-3 with 3-segmented exopod and 2-segmented endopod. Leg 4 uniramous, with 1-segmented exopod. Leg 5 represented by 3 setae; free exopod absent. Leg 6 represented by 1 seta. Gender is feminine.

Etymology. The generic name Sewelloya is an anagram of the “Yellow Sea” where the type locality is located in. It also is in memory of R. B. Seymour Sewell (1880- 1964) who was a British military doctor and copepod researcher.

Type species. Sewelloya plana n. sp.

Remarks. Three known species of Polyankylis are very closely similar to one another and they are, in turn, different from Sewelloya plana n. sp. The close similarity of the three species of Polyankylis and their difference from the latter species suggest placing the new form in a separate genus. Sewelloya n. gen. differs from Polyankylis mainly in forms of the female maxilliped and leg 5. In the female maxilliped of Sewelloya n. gen. the basis (second segment) has two small setae which contrast to the very large ones in the species of Polyankylis . The endopod (distal segment) of the same appendage of Sewelloya is simplified as a short and tapering segment bearing two small setae in contrast to the complicated structure in Polyankylis where the endopod bears an elongated claw or spine and two other elements (setae or spines). Leg 5 of Sewelloya is represented by three setae. In contrast, leg 5 of Polyankylis uniformly consists of a lateral seta on somite and a free exopod bearing one seta and one setiform spine.

Less importantly, the mandible of Sewelloya carries only a single outer sines (vs. a pair of spines in Polyankylis ) at the base of blade, and the antennule in the male of Sewelloya has only one additional aesthetasc on the second segment (vs. two aesthetascs on the second segment and one on the third in Polyankylis ). These are also considered to be differences in generic level.