Bradyidius sp. B

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 : 360

Bradyidius sp. B

( Fig 11 )

Material. One female (specimen 1) from the Pacific Ocean, body length not measured (poor condition), collected above the sea bed in the Kurile-Kamchatka Trench, at Sta. 3–9 on 05 August 2012, 47°14.66’ N 154°42.88’ E, by the KuramBio 1 expedition, Sonne cruise SO 223, at a depth of 4987 m; 1 female in poor condition (specimen 2), from the Pacific Ocean, body length 2.20 mm, collected above the sea bed in the Kurile-Kamchatka Trench, at Sta. 85 on 15 September 2016, 45°01.73’ N 151°03.48’ E, by the KuramBio 2 expedition, Sonne cruise SO 250, at a depth of 5228 m.

Description. Female. Body length 2.20 mm. Prosome 3.4 times as long as urosome. Rostrum two-pointed, not divergent in specimen 1 ( Fig. 11C–D ) and with closely spaced points in specimen 2. Cephalosome and pedigerous somite 1 fused, pedigerous somites 4–5 incompletely separate; posterior corners prolonged into short points, covering the proximal third of genital double-somite ( Fig. 11A–B, E ). Urosome of 4 somites. Genital double-somite symmetrical, in its anterior half with moderately developed lateral swellings (dorsal view). Spermathecae narrowelongate and rounded in distal part ( Fig. 11E ). Caudal rami with 1 lateral seta, 1 ventral seta, and 4 terminal setae.

Antennule broken.

Antenna in specimen 2 ( Fig. 11F ), coxa with 1 seta, basis with 2 setae; exopod of 8 segments, setation formula 0,0-1-1, 1, 1, 1, 1, 1, and 3 setae, endopod segment 1 with 2 setae, segment 2 with 8+7 setae; broken in specimen 1.

Mandible in specimen 2 ( Fig. 11G–H ), gnathobase with 8 teeth; basis with 2 setae; exopod broken; endopod segment 1 with 2 setae, segment 2 with setae broken; in specimen 1 basis with 1 seta.

Maxillule ( Fig. 11I ), praecoxal arthrite with 9 terminal spiniform setae, 4 posterior and 1 anterior setae (anterior seta not observed in specimen 1), coxal endite with 5 setae; coxal epipodite with 7 long+2 short setae (broken in specimen 1); proximal basal endite with 4 setae, tubercle visible, distal basal endite with 5 setae; endopod setae broken; exopod with 10 setae.

Maxilla, endites and the enditic lobe of endopod typical for the genus; endopod segment 1 with 1 long+1 short setae; specimen 1 with 1 long+1 short setae at endopod segment 2 while in specimen 2 only 1 seta was observed at each of endopod segments 2 and 3.

Maxilliped typical for the genus.

Legs. P1 ( Fig. 11J–K ), coxa with or without 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 to 3 with 1 lateral spine each; spine of exopod segment 1 significantly exceeding base of lateral spine at exopod segment 2 ( Fig. 11J–K ).

P2–P4. P4 exopod segments 2 and 3 broken in other characters as in B. kurilokamchaticus sp. nov.

P5 absent.

Male unknown.

Remarks. Due to the poor condition of the single individual the specimen is designated as Bradyidius sp. B without biological name. Bradyidius sp. B . shows close resemblance to B. curtus in the following characters: a rostrum with nondivergent points and prosome posterior corners short, covering only proximal third of the genital double-somite. Bradyidius sp. B . can, however, not be attributed to the species B. curtus due to the absence of the proximal seta at the antenna exopod segment 2 (which is present in B. curtus ) and the longer lateral spines at the exopod segments of P1. The exopod segment 1 lateral spine is exceeding the base of the lateral spine at exopod segment 2 (vs not exceeding the base of exopod segment 2 lateral spine in B. curtus ) and the exopod segment 2 lateral spine is strongly extending over the base of the lateral spine of exopod segment 3 (vs thick short spine not reaching the base of the exopod segment 3 lateral spine in B. curtus ) ( Markhaseva, 1996).

Figures

FIGURE 11. Bradyidius sp. B. Female, A, habitus, dorsal view; B, habitus, lateral view; C, rostrum, ventral view; D, rostrum, lateral view; E, posterior prosome somite and genital double-somite, lateral view; F, antenna, exopod; G, mandible palp, basis and endopod; H, mandible, gnathobase; I, maxullule, proximal basal endite; J, P1, left; K, P1 right, endo- and exopod.