Schizoproctus frigidus 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 frigidus; Antarctic; Antarctic Ocean; Seta; Tenna; Antarc*
• Online Access: https://zenodo.org/record/5047119; https://doi.org/10.5281/zenodo.5047119

Schizoproctus frigidus sp. nov. (Figs. 73, 74) Type material. Holotype ♀ (MNHN-IU-2018-1980, dissected and mounted on a slide) from Cçrella antarctẚca Sluiter, 1905; Antarctic Ocean, Eltanin cruise 12, Stn 1078 (61°26´S, 41°55.4´W), depth 604 m, 12 April 1964. Etymology. The specific name is derived from the Latin frẚg (cold), referring to its discovery in Antarctic waters. Description of female. Body (Fig. 73A) robust, 2.88 mm long. Anterior part of body unsegmented and inflated; cephalosome defined from metasome by faint dorsal constriction. Posterior part of body (Fig. 73B) consisting of genital somite and 4-segmented abdomen. Genital somite much wider than long (205×487 μm) incompletely ar- ticulated from first abdominal somite. First and second abdominal somites 354×436 and 230×385 μm, respectively; third and fourth abdominal somites indistinctly articulated from each other, 128×297 and 210×270 μm, respectively. Caudal ramus (Fig. 73C) about 107×135 μm, armed with 4 claws and 2 setae; lengths of claws 58, 76, 50, and 25 μm from inner to outer. Rostrum (Fig. 73D) broad, steeply tapering towards nipple-shaped, semicircular apex. Antennule (Fig. 73E) 252 μm long and indistinctly 5-segmented; first segment broad, forming right angle with distal 4 segments; 2 distal articulations incomplete; armature formula 11, 6, 3, 2, and 8+aesthetasc. Left antenna (Fig. 73F) consisting of unarmed coxa, basis and unsegmented endopod; endopod 163× 65 μm, armed with 8 short setae and with rudimentary suture line subdistally defining proximal 3-setae part and distal 5-setae part; longest distal seta 96 μm. Right an- tenna segmented and armed as left antenna; endopod (Fig. 73G) 167×65 μm, subdivided by subdistal sclerotization band. Labrum (Fig. 73H) much broader than long, with large, soft posteromedian protuberance. Mandible (Fig. 73I) as usual for genus, with 3 teeth on coxal gnathobase and 9 setae on palp. Maxillule (Fig. 73J) with 8 setae on arthrite, distal seta rudimentary; palp unsegmented with vestigial seta representing ...