Bradyidius sp. A

Markhaseva, Elena L. & Renz, Jasmin, 2021, Description of three new species of Bradyidius (Copepoda: Calanoida), the new aetideids from the deep Pacific Ocean, with notes on the genera Bradyidius and Aetideopsis, Zootaxa 5004 (2), pp. 343-369 : 358

Bradyidius sp. A

( Fig 10 )

Material. One female in poor condition from the Weddell Sea, collected above the sea bed at Sta. 074 on 20 February 2005, 71°18.42’ S 13°58.21’ W, by the ANDEEP 2 expedition, Polarstern cruise ANT XIX –3, at a depth of 1032 m .

Description (limbs in poor condition, only partly described). Female. Body length 2.25 mm. Prosome 4.40 times as long as urosome. Rostrum two-pointed, divergent ( Fig. 10C ). Cephalosome and pedigerous somite 1 separate, pedigerous somites 4–5 fused ( Fig. 10A–B ); posterior corners prolonged into points broken at tips, remaining part reaching posterior border of genital double-somite ( Fig. 10A ). Urosome of 4 somites. Genital double-somite symmetrical, with significant lateral swellings in its anterior half (dorsal view). Spermathecae narrow-elongate and oval in distal part ( Fig. 10B ). Caudal rami with 1 lateral seta, 1 ventral seta, and 4 terminal setae.

Antennule reaching posterior border of genital double-somite.

Antenna ( Fig. 10D ), exopod of 8 segments, setation formula 0,0-1-1, 1, 1, 1, 1, 1, and 3 setae.

Mandible, basis with 2 setae; exopod broken; endopod segment 1 with 2 setae, segment 2 with setae 8 long and 1 short setae.

Maxillule, praecoxal arthrite with 9 terminal spiniform setae and 1 anterior setae, posterior setae broken; coxal endite with 5 setae; coxal epipodite broken; proximal basal endite with 4 setae, distal basal endite with 5 setae; endopod with 16 setae; exopod with 10 setae.

Maxilla, typical for the genus, endopod setation not observed.

Maxilliped typical for the genus.

Legs. P1 ( Fig. 10E ), coxa with lateral spinules; basis with medial distal seta curved with setules; endopod 1- segmented with lateral lobe, its lateral margin with spinules, anterior segment surface with distal spinules; exopod segments 1–3 with 1 lateral spine each; spine of exopod segment 1 slightly exceeding base of exopod segment 2 lateral spine.

P5 absent.

Male unknown.

Remarks. This is the second registration of the genus Bradyidius in the Antarctic, documented, at least by brief taxonomic remarks. The first time the genus was recorded by Wolfenden (1911) from a depths of 1200m and 3000m in the net tows from the Gauss-Station in March 1903 between 64– 68°S and 84– 88°E. Wolfenden identified two obtained specimens as Bradyidius armatus as he could not find any significant difference between the Antarctic and the North Sea specimens. Due to its poor shape the herein given specimen is designated as Bradyidius sp. A ., without biological name. It differs from B. armatus in: 1) size, that is smaller (2.25 mm) than that of B. armatus (2.65–2.70mm) and in the antenna exopod segment 2 armament, that is supplied by 2 setae (vs 3 setae present in B. armatus , as revised by Markhaseva, 1993, fig. 6).

Figures

FIGURE 10. Bradyidius sp. A. Female, A, habitus, dorsal view; B, habitus, lateral view; C, rostrum, ventral view; D, antenna, exopod; E, P1.