Kelleriella, Kim, 2021

Kim, Jae-Sang Hong and Il-Hoi, 2021, Copepods of the family Kelleriidae (Crustacea, Copepoda, Cyclopoida) from tropical waters of the Asia-Pacific, Journal of Species Research 10 (4), pp. 364-386 : 383

Kelleriella n. gen.

Diagnosis (female). Kelleriidae . Body cyclopiform. Urosome 5-segmented. Caudal ramus with 6 setae. Rostrum distinct. Antennule 7-segmented, with armature formula 4, 13, 6, 3, 4 + aesthetasc, 2 + aesthetasc, and 7 + aesthetasc. Antenna 4-segmented; armature formula 1, 1, 3, and 6 + claw; distal claw strong and recurved. Labrum with tapering posterolateral lobes. Mandible slender, with elongate distal lash, spinulose inner margin, denticulate outer margin, and tuft of spinules on proximal convex side of gnathobase. Maxillule lobate, armed with 4 setae. Maxilla consisting of large, unarmed syncoxa and smaller basis; basis with 3 setae including spiniform inner seta, short spiniform distal lash, and few spines along distal margin. Maxilliped 3-segmented; first segment (syncoxa) unarmed; second segment (basis) with 2 spiniform setae; third segment (endopod) small, bearing 1 claw and 2 setiform elements. Legs 1-3 with 3-segmented rami. Leg 4 with 3-segmented exopod and 1-segmented endopod. Armature formula for leg 1-4 as in Kelleria , except third exopodal segment of leg 4 bearing 4 spines and 5 setae (formula III, I, 5, instead of II, I, 5 of Kelleria ). Legs 5 and 6 similar to those of Kelleria .

Type species. Kelleriella quadridens n. gen. n. sp. by monotypy.

Etymology. The generic name is the combination of Kelleria , the type genus of the family, and - ella, a Latin diminutive suffix. Gender feminine.

Remarks. Kelleriella n. gen. is here treated as a genus of the family Kelleriidae , based on its following features: (1) the mandible has a tuft of thin spinules on the outer side at the base of the gnathobase, as usual for the type genus, Kelleria ; (2) the genital aperture is large, with a posterolaterally displaced seta; (3) the basis (distal segment) of the maxilla has a short, spiniform distal lash and large spines along distal margin; and (4) the endopod of leg 4 is 1-segmented (as in the families Macrochironidae and Pseudanthessiidae ) and bears an inner seta (unlike the latter two families).

The Kelleriidae has been a monotypic family consisting of 21 species of Kelleria , all of which have the uniformed antenna and armature formula of leg 4. In the antenna of this genus the second endopodal segment is armed with 1 setiform claw plus 2 setae, and the third endopodal segment with 2 setiform claws plus 5 setae. In leg 4 of Kelleria the third exopodal segment is armed with 3 spines plus 5 setae (formula II, I, 5). In contrast, the antenna of Kelleriella quadridens n. gen. n. sp. is armed with 3 simple setae on the second endopodal segment and 1 powerful claw plus 6 setae on the third endopodal segment, and its third exopodal segment of leg 4 is armed with 4 spines plus 5 setae (formula III, I, 5). Due to these armature conditions in the antenna and leg 4 exopod, the new species cannot be placed within the genus Kelleria . According to Humes & Boxshall (1996), the female maxilliped of the Kelleriidae exhibits a key character of the family, in which the third segment (endopod) bears four discrete setation elements. Thus, the maxilliped of the new genus is unusual for the Kelleriidae in bearing 1 claw plus 2 setiform elements on the third segment (endopod). On the basis of the above characteristic features of Kelleriella quadridens n. gen. n. sp. revealed in the antenna, leg 4, and female maxilliped, the new genus Kelleriella is established to accommodate the new species.