Sensiava secunda Markhaseva, 2014, sp. nov.

• Main Author: Markhaseva, Elena L.
• Format: Text
• Language: unknown
• Published: Zenodo 2014
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Maxillopoda; Calanoida; Diaixidae; Sensiava; Sensiava secunda; Weddell Sea; Weddell; Seta
• Online Access: https://dx.doi.org/10.5281/zenodo.6140730; https://zenodo.org/record/6140730

Sensiava cf. secunda sp. nov. (Figs 5–8) Material examined. Three adult males, body length 2.80–3.00 mm. Collected by the DIVA –II expedition above the sea bed in the South Atlantic: 1 male, 15 March 2005, 00º09’S 02º 30 ’W, at a depth of 5054 m; 1 male, 20 March 2005, 00º 45 ’S 05º 35 ’W, at a depth of 5142 m; and 1 male, 20 March 2005, 00º 43 ’S 05º 31 ’W, at a depth of 5142 m. Description. Male. Body length 2.80–3.00 mm. Prosome 2.2–2.6 times as long as urosome (Fig. 5 A–B). Rostrum as 2 filaments (Fig. 5 C). Cephalosome and pedigerous somite 1 incompletely separate, and pedigerous somites 4 and 5 completely separate; posterior corners in dorsal view obtuse-triangular; as short rounded lobes in lateral view (Fig. 5 A–B). Urosome of 5 somites (Fig. 5 A–B). Caudal rami with 1 dorsal seta, 1 ventral seta, and 4 terminal setae (Fig. 5 D). Antennule (Fig. 6 A–D, 7 A–B) nearly as long as body, right (Fig. 6 A–D), of 23 articulating segments, segments XIX to XXIII transformed, compared to left; armature as follows: I– 1 s + 1 ae, II– IV– 6 s + 2 ae + 2, V– 2 s + 2?, VI– 2 s + 1?, VII– 2 s + 2 ae, VIII– 2 s + 1 ae, IX– 2 s + 2 ae, X– XI– 3 s + 3 ae, XII– 1 ae, XIII– 1 ae, XIV– 2 s + 1 ae, XV– 1 s + 1 ae, XVI– 2 s (1 seta curved), XVII– 2 s+ 1 ae, XVIII– 2 s + 1 ae, XIX– 1 s + 1 ae + 1 spine, XX– 1 s + 1 ae + 1 spine, XXI– 1 s + 1 ae, XXII–XXIII– 1 s + 1 spine, XXIV– 2 s, XXV– 2 s, XXVI– 2 s, XXVII–XXVIII– 5 s + 1 ae. Left (7 A–B) antennule of 24 articulating segments, armature as follows: I– 1 s + 1 ae, II– IV– 6 s + 4 ae, V– 2 s + 2 ae, VI– 2 s + 1 ae, VII– 2 s + 2 ae, VIII– 2 s + 1 ae, IX– 2 s + 2 ae, X– XI– 3 s + 3 ae, XII– 1 ae, XIII– 1 ae, XIV– 2 s + 1 ae, XV– 1 s + 1 ae, XVI– 2 s + 1 ae, 1 seta curved, XVII– 1 s + 1 ae, XVIII– 2 s + 1 ae, segments XIX to XXIII not transformed, their armature as follows: XIX– 1 s + 1 ae, XX– 1 s + 1 ae, XXI– 1 s + 1 ae, XXII– 1 s, XXIII– 1 s. Oral parts and swimming legs as in females, except for: i) in antenna endopod segment 2 with only 5 + 5 setae saved, other setae broken, precise setae number not observed; ii) mandible basis with 2 setae (endopod damaged); iii) maxillule with one of 4 coxal setae small; iv) maxilla praecoxal endite (previously considered as proximal praecoxal endite) with 4 setae and a small attenuation (vs 5 setae in female) and maxilla endopod with 3 worm-like and 5 brush-like sensory setae (vs additional 1 small slerotized seta in female); v) maxilliped endopod segment 5 with 2 very long setae (Fig. 7 D vs Fig. 3 E), and vi) P 4 posterior surface of coxa, basis, exopod and endopod with sparse spinulation compared to females. P 5 (Fig. 8 A–E), asymmetrical, with uniramous right leg (small rudiment of endopod present), and biramous left leg; coxae fused, of similar size, left basis slightly longer than right. Right leg exopod 3 -segmented; segment 2 with small spine distally, segment 3 spine-like and tapering distally. Left leg with 2 -segmented exopod, segment 1 with moderate medial projection and small lateral spine, segment 2 of complex structure (Fig. 8 D–E), with cavity opening terminally surrounded by rows of spinules anteriorly and posteriorly. Left endopod 1 -segmented, curved, longer than 2 -segmented exopod, with terminal spine-like attenuation. Remarks. Sensiava secunda sp. nov . female is distinguished from its congeners by the following combination of characters: i) shape and moderate size of spermatheca, which is only slightly upturned anteriorly ( vs. large, or elongate, strongly directed anteriorly spermatheca in other congeners, Figs 9 F,G; 13 A, 14 A); ii) one seta at the antenna basis is very short (shared with S. peculiaris sp. nov. , vs. this seta is much longer in S . cf. longiseta and Sensiava sp. , Figs 13 B and 14 B); iii) maxilla endopod with 1 small sclerotized seta plus 3 worm-like and 5 brushlike sensory setae ( vs. 3 worm-like and 5 brush-like sensory setae in other congeners); iv) maxilliped syncoxa with 1 sclerotized seta on proximal praecoxal endite, 2 sclerotized setae on middle praecoxal endite and 3 sclerotized setae, 1 with poorly developed brush, on distal praecoxal endite; ( vs. different setal arrangements in other congeners, e.g. Figs 11 C, 13 F); v) lateral spines of P 1 exopod segments 1 to 3 with distal half attenuated into a thread-like apex ( vs. tapering to stiff point or slightly attenuated, Fig. 13); vi) P 1 endopod lateral lobe without spinules (shared with all congeners, except for S. peculiaris, which has a lobe ornamented with spinules); vii) female P 5 coxa slightly more elongate than basis; exopod with 4 distal spines partly or completely separate from the segment, medial is the longest ( vs. coxa slightly less elongated than basis and exopod with 1 subterminal attenuation and 3 spines completely separate in S. peculiaris data for the other congeners absent due to poor condition of this limb). Sensiava cf. secunda males are much smaller (2.80–3.00 mm) than the described males of S. longiseta (4.60- 4.80 mm). They differ from the males of S. longiseta also in: i) the shape of the geniculated antennule transformed segments XIX–XXIII (see Markhaseva & Schulz 2006, Fig. 2 C); ii) presence of 4 setae on the coxal endite of maxillule ( vs. 3 setae in S. longiseta ); iii) presence of a small brush at the seta of the distal praecoxal setal group of maxilliped (brush absent in S. longiseta ); and a different shape of left P 5 exo- and endopods (see Markhaseva & Schulz 2006, Fig. G–L). These male specimens are similar to females of S. secunda in size and share with those females a general shape of oral limbs and the swimming leg setation. However, they differ in some details and thus are currently tentatively attributed to this species, as Sensiava cf. secunda . : Published as part of Markhaseva, Elena L., 2014, New Sensiava species (Copepoda: Calanoida: Diaixidae) from the deep South Atlantic and first description of the female, pp. 217-239 in Zootaxa 3802 (2) on pages 223-228, DOI: 10.11646/zootaxa.3802.2.5, http://zenodo.org/record/228328 : {"references": ["Markhaseva, E. L. & Schulz, K. (2006) Sensiava longiseta (Copepoda, Calanoida): a new genus and species from the abyss of the Weddell Sea. Zootaxa, 1368, 1 - 18."]}