( Figs 5–8)
Holotype. Adult female, dissected, body length 2.10 mm. ZMH 45138. Collected above the sea bed in the Kurile- Kamchatka Trench at Sta. 2–10, 46° 14.76’ N 155° 32.81’ E, on 3 August 2012 by the KuramBio 1 expedition, Sonne cruise SO 223, at depths between 4859 and 4865 m.
Paratypes. 5 adult females, partly dissected, body length 2.20, 2.20, 2.20, 2.30 and 2.30 mm. SMF 37208– 37212, collected above the sea bed in the Kurile-Kamchatka Trench, by the KuramBio 1 expedition, Sonne cruise SO 223 at Sta. 9–12 on 24 August 2012, 40°34.49’ N 150°59.85’ E, at depths between 5399 and 5392 m; 2 adult females, 1 in poor condition, body length 2.00, 2.15 mm, ZIN 91147, Sta. 11–12, 31 August 2012, 40°12.32 ‘ N 148° 05.73’ E, at depths between 5350 to 5348 m.
Type locality. 46°14.77’ N 155°32.79’ E.
Additional material. Four females from the Atlantic Ocean: 1 female, body length 2.15 mm, collected in the Angola Basin, Sta. 348, 27 July 2000, 16°16.98’ S 005°27.27’ E, by the DIVA–1 expedition, Meteor cruise ME 48–1, at a depth of 5390 m; 2 females collected in the Guinea Basin by the DIVA–2 expedition, Meteor cruise ME 63–2 from 2 stations – 1 female, body damaged, not measured, Sta. 64–5, 15 March 2005, 00°13.27’ S 002°29.91’ W, depth 5055 m and 1 female, body length 2.05 mm, Sta. 89–6, 20 March 2005, 00°45.30’ S 005°35.00’ W, depth 5154 m; 1 female, body length 1.90 mm, collected at Meteor Seamount, Sta. 636, 18 August 2009, 29°19.24’ N 28°37.94’ E, by the DIVA–3 expedition, Meteor cruise ME 79–1, at a depth of 4338 m. One female from the Pacific Ocean, body length not measured, collected above the sea bed in the Kurile-Kamchatka Trench, at Sta. 7–10 on 17 August 2012, 40°01.82’ N 152°58.55’ E, by the KuramBio 1 expedition, Sonne cruise SO 223, at depths between 5223 and 5221 m.
Description. Female. Body length 1.90–2.30 mm. Prosome 2.7–3.3 times as long as urosome ( Fig. 5 A–B). Rostrum as a significantly reduced blunt plate ( Fig. 5C). Cephalosome and pedigerous somite 1 and pedigerous somites 4–5 incompletely separate; posterior corners oval-triangular in dorsal view; rounded in lateral view ( Fig. 5 A–B, E–H). Urosome of 4 somites ( Fig. 5 A–B). Genital double somite globular shape. Spermathecae large, round to oval round with very narrow duct leading to the genital atrium ( Fig. 5B, F–H). Caudal rami with 1 lateral seta, 1 ventral seta, and 4 terminal setae ( Fig. 5D).
Antennule ( Fig. 5 J–L) reaching pedigerous somite 3, of 24 articulating segments; armature as follows: I–3s, II–IV–6s+1ae (ae absent in holotype), V–2s+1ae, VI–2s, VII–2s+1ae, VIII and IX–2s each, X–XI–4s+1ae, XII and XIII–2s each, XIV–2s+1ae, XV–2s, XVI–2s+1ae, XVII to XXI–2s each, XXII and XXIII–1s each, XXIV–XXVI– 2s each, XXVII–XXVIII–5s+1ae, aestethasc long, nearly as long as 3 preceding segments together.
Antenna ( Fig. 6 A–C), coxa with 1 seta, basis with 2 setae; exopod of 8 segments, setation formula 1?0?1?1, 1, 1, 1, 1, 1, and 3 setae (uncertain whether proximal Enp 1 and 2, or Enp 2 and 4 are fused), all terminal setae long, of nearly the same length; first endopodal segment with 2 setae, second with 8–9 + 7 setae.
Mandible ( Fig. 6 D–E), gnathobase with 4 large and 4 small teeth near dorsal seta; basis with 2 setae; exopod 5-segmented with 1, 1, 1, 1, and 2 setae; endopod segment 1 with 2 setae, segment 2 with 9+1, or 9 setae in paratype.
Maxillule ( Fig. 6F), praecoxal arthrite with 9 terminal, 4 posterior and 1 anterior setae, coxal endite with 5 setae; coxal epipodite with 7 long+2 short setae; proximal basal endite with 4 setae, distal basal endite with 5 setae; endopod with 16 setae; exopod with 9–10 setae.
Maxilla ( Fig. 7 A–B), praecoxal to basal endites with 3 setae each, all endites decorated with denticles; enditiclike lobe of proximal endopod segment with 3 setal elements, two thicker, spine-like; endopod with 9 (2+2+2+3) setae.
Maxilliped ( Fig. 7 C–E), syncoxa with 1 seta on proximal praecoxal endite, 2 setae on middle praecoxal endite and 3 setae on distal praecoxal endite; coxal lobe with 3 setae and conical tubercle. Basis with 3 setae. Endopod 6- segmented with 2, 4, 4, 3, 3+1, and 4 setae, first segment very small and fused to basis.
Legs. P1 ( Fig. 6G), coxa with lateral spinules; basis with small lateral spinule distally and 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 usually exceeding base of segment 2 lateral spine, sometimes, reaching base of segment 2 lateral spine. P2–P4 ( Fig. 8 A–C), coxa with 1 medial seta and medial spinules; basis without seta; endopod 2-segmented in P2, 3-segmented in P3–P4; posterior surface spinules present on P2 endopod segment 2 (nude in holotype), P3 endopod segment 3, and P4 endopod segments 2–3 (nude in holotype); exopods 3-segmented. P5 absent.
Male unknown.
Etymology. The species name “ paramatthei ” refers to a close relation of the species to Bradyetes matthei Johannessen, 1976.
Remarks. The new species is closely related to B. matthei and shares with this species a significant number of morphological features ( Table 3), but differs from B. matthei in the shape of the posterior corners of Pd5, which are rounded ( vs drawn out into the triangular points in B. matthei) and in the armament of the proximal segment of the antennal exopod, which bears a seta ( vs seta absent in B. matthei).
While Bradyetes paramatthei sp. nov. and B. matthei both inhabit the near-bottom biotope, they are widely separated geographically and live in distant depth zones. Bradyetes matthei is recorded only from its type locality (Fensfjord, about 60° N 05° E) at depths between 548 and 580 m ( Johannessen 1976, Markhaseva 1996), whereas the new species was collected at abyssal depths between 4338 and 5399 m in the North and South Atlantic Ocean (several localities between 29° N and 16° S: Angola and Guinea basins, Meteor Seamount) and in the Pacific Ocean (Kurile-Kamchatka Trench).