Sensiava peculiaris, Markhaseva, Elena L., 2014

Markhaseva, Elena L., 2014, New Sensiava species (Copepoda: Calanoida: Diaixidae) from the deep South Atlantic and first description of the female, Zootaxa 3802 (2), pp. 217-239 : 228-233

Sensiava peculiaris sp. nov.

( Figs 9–12 )

Holotype. Dissected adult female, body length 2.95 mm. ZMH Reg. no. K–42425. Collected on 15 March 2005 by the DIVA –II expedition above the sea bed at abyssal depths (5147 m).

Paratypes. Dissected, body length 2.80–3.00. ZIN. K–91118, 2 adult females, the same label data as for the holotype. Additional material: 6 females, body length 3.00–3.10 mm. 1 female in a bad shape, same locality data as for holotype; 1 female collected on 28 July 2000 by the DIVA –I, 16º18’S 05º27’E, at a depth of 5430 m; 2 females collected on 15 July 2009 by the DIVA –III, 36º00’S 49º02’W, at a depth of 4602 m; 1 female collected on 16 July 2009 by the DIVA –III, 36º01’S 49º02’W, at a depth of 4608 m; 1 female collected on 0 5 August 2009 by the DIVA –III, 03º58’S 28º05’W, at a depth of 5180 m.

Description. Female. Body length 2.80–3.10 mm. Prosome 3.7–4.1 times as long as urosome ( Fig. 9 A–B). Rostrum as 2 filaments ( Fig. 9 C). Cephalosome and pedigerous somite 1 incompletely separate, and pedigerous somites 4 and 5 completely separate; posterior corners in dorsal view triangular; as short rounded lobes in lateral view ( Fig. 9 A–B, E–F). Urosome of 4 somites ( Fig. 9 E–F). Spermatheca, elongate, narrow and rounded distally, directed anteriorly ( Fig. 9 F, G). Caudal rami with 1 dorsal seta, 1 ventral seta, and 4 terminal setae.

Antennule ( Fig. 10 A–B) nearly as long as body, or reaching to caudal rami, of 24 articulating segments; armature as follows: I–3 s, II– IV–6 s + 1ae, V–2 s + 1ae, VI–2 s, VII–2 s + 1ae, VIII–2 s, IX–2 s + 1ae, X– XI–4 s + 1ae, XII–1 s, XIII–1s, XIV–2s + 1ae, XV–1s, XVI–2s + 1ae, XVII–1s, XVIII–2s, XIX–1s, XX–2s, XXI–1s + 1ae, XXII–1?, XXIII–1s, XXIV–2s, XXV–2s, XXVI–2s, XXVII–XXVIII–4s + 1ae.

Antenna ( Fig. 10 C), coxa with 1 seta, basis with 2 setae, one seta very short; exopod of 7 segments with 0, 0-1- 1, 1, 1, 1, 1, 1, and 3 setae; first endopodal segment with 1 seta, second with 8 + 6 setae.

Mandible ( Fig. 10 D–E), gnathobase without crest, cutting edge with 5 large and 3 small teeth near dorsal seta; basis with 3 setae; exopod 5-segmented with 1, 1, 1, 1, and 2 setae; endopod segment 1 with 2 setae, segment 2 with 9 setae.

Maxillule ( Fig. 10 F), praecoxal arthrite with 9 marginal, 3 posterior and 1 anterior setae, distalmost praecoxal arthrite terminal seta curved at the apex; coxal endite with 4 setae; coxal epipodite with 7 long and 1 short seta; proximal basal endite with 4 setae, distal basal endite with 4 setae; endopod with 9 (3+6) setae; exopod with 8 setae.

Maxilla ( Fig. 11 A–B), praecoxal endite (previously considered as proximal praecoxal endite) with 4 setae and 1 small attenuation; coxal endite (previously considered as distal praecoxal endite) with 3 setae; basal endites (previously considered as coxal endites) with 3 setae each, 1 seta of proximal basal endite sensory, worm-like; enditic-like lobe of proximal endopodal segment (previously considered as proximal basal endite) with 4 setae (2 sensory and worm-like); setae of the maxilla basal endites and enditic-like lobe of endopod are similar in shape and size, curved distally; endopod with 3 worm-like and 5 brush-like sensory setae.

Maxilliped ( Fig. 11 C), syncoxa with 1 sclerotized seta on proximal praecoxal endite, 1 worm-like and 1 sclerotized setae on middle praecoxal endite and 2 sclerotized and 1 worm-like setae on distal praecoxal endite; coxal lobe with 3 setae. Basis with 3 proximal setae and 2 distal setae. Endopod 5-segmented with 4, 4, 3, 3+1, and 4 setae.

Swimming legs. P1 ( Fig. 11 D), coxa with medial spinules; basis with medial spinules, small posterior spines at base of medial distal seta curved with setules and small lateral spine; endopod 1-segmented with lateral lobe, lateral margin with spinules; exopod segments 1 to 3 with 1 lateral spine each, spines tapering to stiff point. P2–P4 ( Fig. 12 A–C), coxa with 1 seta; basis without seta, with small denticles distomedially; endopod 2-segmented in P2, with posterior spinules, 3-segmented in P3–P4 with posterior spinules; exopods 3-segmented. Posterior surface of P4 coxa, basis and exopod spinulated.

P5 ( Fig. 12 D) 3-segmented, composed of coxa, basis and 1-segmented exopod; coxa slightly shorter, than basis; coxa with sparse small spinules distolaterally, basis with distolateral patch of spinules, exopod ornamented with dense surface spinules, with 1 subterminal attenuation and 3 spines completely separate from segment, medial spine longest.

Type locality. South Atlantic (00º01’S 02º29’W).

Etymology. The species name refers to the peculiar setation of the second to proximal exopodal segments of the antenna.

Remarks. Sensiava peculiaris sp. nov. is distinguished from its congeners by the following combination of characters: i) a unique shape of spermatheca (vs. different shape in other congeners, Figs 1 F–G, 13A, 14A); ii) one of 2 setae at the antenna basis is very short (shared with S. secunda sp. nov., vs. this seta is much longer in S. cf. longiseta and Sensiava sp., Figs 13 B, 14 B); iii) antenna exopod setation as 0, 0-1-1, 1, 1, 1, 1, 1, and 3 setae (vs. 0, 0-0-1, 1, 1, 1, 1, 1, and 3 setae in other congeners); iv) maxillule praecoxal arthrite with 3 posterior setae (shared with Sensiava sp., vs. 4 posterior setae in other congeners); v) maxillule coxal epipodite with 7 long and 1 short seta (share with Sensiava sp., vs. 7 long and 2 short setae in other congeners); vi) maxilla, praecoxal endite with 4 setae and 1 small attenuation; vii) maxilliped syncoxa with 1 sclerotized seta on proximal praecoxal endite, 1 sclerotized and 1 worm-like sensory setae setae on middle praecoxal endite, and 2 sclerotized setae and 1 wormlike sensory seta distal praecoxal endite; (vs. all setae sclerotized, 1 with small brush in S. secunda ; all setae sclerotized, 1 poorly sclerotized in Sensiava cf. longiseta , and 1 sensory worm-like seta on proximal praecoxal endite, 1 sclerotized setae and 1 sensory worm-like seta on middle praecoxal endite and 2 sclerotized and 1 sensory seta with a very small brush on distal praecoxal endite in Sensiava sp.); viii) lateral spines of exopod segments 1 to 3 pf P1 taper to a stiff point (shared with all congeners, except for S. secunda ); ix) endopod lateral lobe lateral margin with spinules (vs. spinules absent in other congeners); x) P5 coxa slightly shorter than the basis and exopod, with 1 subterminal attenuation and 3 spines completely separate (vs. coxa slightly longer than the basis; exopod with 4 distal spines partly or completely separate from the segment, medial is the longest in S. secunda ).

Figures

FIGURE 1. Sensiava secunda sp. nov. Female, holotype. A, habitus, dorsal view; B, habitus, lateral view; C, rostrum, lateral view; D, urosome, dorsal view; E, genital double somite, ventral view; F, urosome, lateral view; G, genital field, lateral view; H, P 5, posterior view. Scale bars: A – B 0.5 mm, C – H 0.1 mm.

FIGURE 9. Sensiava peculiaris sp. nov. Female, holotype. A, habitus, dorsal view; B, habitus, lateral view; C, rostrum, dorsal view; D, rostrum, lateral view; E, posterior prosome and urosome, dorsal view; F, posterior prosome and urosome, lateral view (dorsal and lateral setae added after paratype); G, genital field, lateral view. Scale bars: A – B 0.5 mm, C – H 0.1 mm.

FIGURE 10. Sensiava peculiaris sp. nov. Female, holotype. A, antennule, articulating segments 1 – 14 (ancestral segments I – XVII); B, antennule, articulating segments 15 – 24 (ancestral segments XVIII – XXVIII); C, antenna; D, mandible; E, mandible, gnathobase; F, maxillule (arrow marks distalmost terminal seta curved at the apex). Scale bars 0.1 mm.

FIGURE 11. Sensiava peculiaris sp. nov. Female, holotype. A, maxilla, sensory setae of endopod are not figured; B, maxilla, sensory setae of endopod; C, maxilliped; D, P 1. Scale bars 0.1 mm.

FIGURE 12. Sensiava peculiaris sp. nov. Female, holotype. A, P 2; B, P 3; C, P 4; D, P 5. Scale bars 0.1 mm.

FIGURE 13. Sensiava cf. longiseta Markhaseva & Schulz, 2006. Female. A, spermatheca, lateral view; B, antenna, coxa, basis, endopod segment 1; C, mandible, cutting edge; D, maxillule (arrow marks distalmost terminal seta curved at the apex); E, maxilla; F, maxilliped syncoxa; G, maxilliped, basis, distal setae not figured; I, P 1. Scale bars 0.1 mm.