Schizoproctus bisetatus Kim & Boxshall 2021, sp. nov.

• Main Authors: Kim, Il-Hoi, Boxshall, Geoff A.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Maxillopoda; Cyclopoida; Ascidicolidae; Schizoproctus; Schizoproctus bisetatus; Linde; Seta; Weddell; Weddell Sea
• Online Access: https://zenodo.org/record/5047111; https://doi.org/10.5281/zenodo.5047111

Schizoproctus bisetatus sp. nov. (Figs. 67, 78) Type material. Holotype ♀ (MNHN-IU-2018-1977, dissected and mounted on a slide) from Caenagnesẚa bçckẚ Ärnbäck-Christie-Linde, 1938 (MNHN-IT-2008-1840 = MNHN P3 / CAE/6); Weddell Sea, EPOS 3 3 cruise, RV “Polarstern”, Stn MG7 (75°05.5´S, 28°01.0´W), depth 462 m, 01 February 1989. Etymology. The name is derived from the Latin bẚ (=two) and set (=a bristle), referring to leg 5 of the new species, which is armed with 2 setae. Description of female. Body (Fig. 67A) symmetrical, narrow, 2.90 mm long. Anterior part of body unsegment- ed; cephalosome defined from metasome by dorsal and lateral constrictions; metasome slightly inflated dorsally with convex dorsal margin in lateral view and narrower posterior part. Legs 4 and 5 positioned on same transverse plane. Posterior part of body (Fig. 67B) slender, consisting of genital somite and 4-segmented abdomen, but articulation incomplete between last 2 somites. Genital somite 394×406 μm; 4 abdominal somites 187×315, 133×300, 188×255, and 242×182 μm, respectively. Caudal ramus (Fig. 67C) as long as wide, ornamented with 2 patches of minute spinules on ventral surface; armed with 5 claws and 1 seta; spine on subdistal inner margin setiform, pale. Rostrum (Fig. 67D) short, strongly tapering towards rounded apex. Antennule (Fig. 67E) 5-segmented, forming right angle between first and remaining segments; armature formula 13, 5, 3, 4, and 7+aesthetasc; aesthetasc on last segment very small and similar in appearance to smaller setae. Antenna (Fig. 67F) consisting of coxa, basis, and 2-segmented endopod; coxa short and unarmed; basis unarmed but ornamented with 2 patches of minute spinules subdistally; first endopodal segment short and unarmed; second endopodal segment about 3 times longer than wide (121×41 μm), with vestigial suture at distal third: armed with 8 spines (4 on inner margin and 4 on distal margin) and ornamented with 1 patch of minute spinules subdistally; fourth spine on inner margin shortest, and second outer spine ...