Doroixys obesa Kim & Boxshall 2020, sp. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Cyclopoida
Notodelphyidae
Doroixys
Doroixys obesa

description: Doroixys obesa sp. nov.
(Figs. 322, 323)
Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21373) from Polyclinum isipingense Sluiter, 1898 (MNHN-IT-2008-XXX = MNHN A1/POL.B/108), ATIMOVATAE TR07, Madagascar (25°01 Ń, 47°00 É), depth 12-16 m, MNHN coll., 01 May 2010.
Etymology. The specific name refers to the obese body form of the female.
CoxaBasisExopodEndopodLeg 10-01-II-1; 1-1; 3, 1, 30-1; 0-1; 1, 2, 3Leg 20-01-01-0; 1-0; 3, 1, 50-0; 0-0; 0, 2, 3Leg 30-01-01-0; 1-0; 3, 1, 50-0; 0-0; 0, 2, 1Leg 40-01-01-0; 1-0; 3, 1, 40-0; 1, 2, 0
Descriptionoffemale. Body (Fig. 322A) stout, ventrally curved; bodylength 1.01 mm. Prosome 808 μm long: dorsal cephalic shield expanded ventrolaterally, with small, paired, dorsally curved horn-likeprocesses (Fig. 322D) posterolaterally. Freeurosome (Fig. 19B) 5-segmented. Caudalramus (Fig. 322C) about 3.2 times longer than wide (89×28 μm) and about twice as long as anal somite, with almost parallel lateral margins and rounded distal margin, ornamented with many scattered setules: armedwith 6 setae (outer lateral, dorsal, and 4 distal) outer lateral and dorsal setae positioned in same plane at 60% length of ramus; all caudal setae small, less than half width of ramus at base.
Rostrum (Fig. 322E) large, 95×53 μm, proximal third with parallel lateral margins, distal two-thirds tapering towards blunt apex. Antennule (Fig. 322F) stout, strongly tapering, 9-segmented, but articulation between seventh and eighth segments incomplete; armature formula 2, 13, 5, 2+aesthetasc, 2, 3, 2, 2, and 7; all setae naked. Antenna (Fig. 322G) stout, 3-segmented, comprisingunarmed coxa and basis and unsegmented endopod; endopod about 2.5 times longer than wide (42×17 μm) and about 0.8 times as long as basis: armedwith 1 middle and 2 distalsetae plus terminal claw, half as long as endopod.
Labrum (Fig. 322H) simple, with narrow setulose posterior margin. Mandible (Fig. 322I) with broadened coxal gnathobase bearing 5 teeth and 1 seta; basis with 1 seta: exopod 2-segmented; first segment armed with 2 equal, large setae; secondsegment with 2 equal, distal setae and 1 small outer seta (about half as long as larger setae): endopod with 1 and 5 setaeon first and second segments, respectively; all setae short, subequal in length. Maxillule (Fig. 322J) armedwith 9 setaeon arthrite, 2 unequal setae on epipodite, 1 on basis, 4 on exopod, and 3 on endopod; coxal endite absent. Maxilla (Fig. 323A) 4-segmented; syncoxa bearing 4, 2, and 2 setae on first to third endites, respectively; basis with smooth claw plus 1 seta; endopod small, lacking setaon first segment, with 3 setae on second segment. Maxilliped (Fig. 323B) lobate, armedwith 6 subequal setae.
Legs 1–3 (Fig. 323 C-E) with 3-segmented rami. Leg 4 (Fig. 323F) with 3-segmented exopod and 2- segmented endopod; second endopodal segment of leg 4 elongate, about 4.2 times longer than wide (54×13 μm), 3.5 times longer than first endopodal segment. Inner coxal seta absent on all swimming legs. Inner distal spine of basis of leg 1 small, 12 μm long. Second exopodal segment of leg 1 bearing outer seta (instead of spine). All setae on swimming legs naked, except feebly pinnate (or spinulose) setae on third exopodal segment of leg 3. Leg 4 asymmetical: outer setae on exopod of left leg 4 slender (as on leg 3), but setae on right leg 4 broad and spiniform (Fig. 323F). Armature formula for legs 1–4 as follows:
Leg 5 (Fig. 322B) represented by 2 tapering, pointed posteroventral processes on surface of somite; outer process smaller; inner exopodal process larger, armed with 1 small seta on outer margin.
Male. Unknown.
Remarks. This is the first species of Doroixys to be characterised by the possession of a 3-segmented antenna, comprising coxa, basis, and an unsegmented endopod, although additional new species sharing the same kind of 3-segmented antenna are described below. Doroixys obesa sp. nov. is unique within the genus in the absence of a seta on the first endopodal segment of the maxilla. Other unusual features include the endopod of the mandible is armed with 6 equal, short setae (1 on first and 5 on second segment, respectively) rather than setae of dissimilar lengths, and the maxillule bears 2 setae on the epipodite rather than the typical single seta. These features are sufficient to distinguish the new species from its congeners.
description: Published as part of 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), pp. 1-6 in Megataxa 4 (1) on page 486, DOI: 10.11646/megataxa.4.1.1, http://zenodo.org/record/4591138