Heptnerina confusa, Ivanenko & Defaye, 2004

Ivanenko, Viatcheslav N. & Defaye, Danielle, 2004, A new genus and species of deep-sea cyclopoid (Crustacea, Copepoda, Cyclopinidae) from the Mid-Atlantic Ridge (Azores Triple Junction, Lucky Strike), Zoosystema 26 (1), pp. 49-64 : 51-57

publication ID	https://doi.org/ 10.5281/zenodo.5401374
publication LSID	lsid:zoobank.org:pub:E70B6263-B5B2-4AB2-9184-07ED438AAE32
persistent identifier	https://treatment.plazi.org/id/03B887D7-0357-FF94-E62B-05C2CB165AA3
treatment provided by	Marcus
scientific name	Heptnerina confusa
status	sp. nov.

Treatment

Heptnerina confusa n. sp.

( Figs 1 View FIG -8)

TYPE MATERIAL. — Holotype (MNHN-Cp2155) . Paratypes: allotype (MNHN-Cp2156); 6, 5, 2 copepodids of stage 5, 4 copepodids of stage 4 (MNHN-Cp2157). The description is based mainly on the holotype female and allotype male. The type material is mounted on slides in glycerol and sealed with Eukitt (O. Kindler GmbH & Co., Freiburg, Germany) and deposited in the Muséum national d’Histoire naturelle, Paris .

TYPE LOCALITY. — Atlantic Ocean, Mid-Atlantic Ridge, Azores Triple Junction, Lucky Strike, cruise PICO, vessel Nadir, submersible Nautile, dive 1270, sample number SMAC A- 1, 37°17.29’N, 32°16.45’W, 1698 m, 7.VII.1998.

ETYMOLOGY. — From the Latin confusus, referring to the difficulty in interpreting the morphological features of the new species.

DESCRIPTION

Holotype female

Body cyclopiform ( Fig. 1A, B View FIG ). Total length, excluding caudal setae: 0.82 mm, greatest width 0.32 mm. First pedigerous somite free, concealed laterally by extension of cephalosome. Tergites of second to fourth pedigerous somites sclerotized laterally and pointed posteriorly. Urosome five-segmented. Genital and first abdominal somites fused to form genital double somite ( Fig. 1C, D View FIG ). Genital field with single medioventral copulatory pore, connecting internally into a wide copulatory tube leading to the seminal receptacle organized into two arms, each extending to dorsolateral gonopore associated with leg 6; accessory rounded structure of unknown function (possibly glandular), present on each side, proximal to seminal receptacle ( Fig. 1D, E View FIG ). Terminal margin of anal somite with ventral row of small spinules. Caudal rami ( Fig. 2A View FIG ) parallel, three times longer than wide, ventral side subdistally lined by row of flattened spinules; bearing seven setae. Accessory lateral seta (seta I) short, difficult to see; inner terminal seta 1.47 times longer than caudal ramus and longer than dorsal and distal outer setae; median inner terminal seta long, 5.3 times longer than caudal ramus and 1.7 times longer than median external seta. Median caudal setae with heteronomous setation.

Egg sacs not observed.

Rostrum ( Fig. 2B View FIG ) weakly developed.

Labrum with anterior outgrowth and patches of setules as shown on Figure 2B View FIG .

Paragnath ( Fig. 2C, D View FIG ) lobate with four spinulate setae, normally covered ventrally by gnathobase of mandible.

Antennule ( Fig. 2 View FIG E-G) 10-segmented; third, fourth and fifth segments subdivided, expressing partially, intersegmental articulations on their medial margin. Setation formula as follows: 3, 5, 8, 4, 6+s, 6+a, 3+a, 2, 2+a, 8+a (s: spine, a: aesthetasc), corresponding to ancestral segments: I- II, III-V, VI-IX, X-XI, XII-XIV, XV-XX, XXI-XXIII, XXIV, XXV, XXVI-XXVIII respectively. First segment ornamented with setules.

Antenna ( Fig. 3A, B View FIG ) consisting of four segments: basis with one inner seta and two external setae representing exopod; endopod three-segmented with setal formula 1, 5, 7. Basis with basal patch of spinules on frontal surface; first endopodal segment with lateral outer distal prominence bearing group of tiny spinules, and with inner margin with two rows of small spinules, one in each half of segment; last endopodal segment with outer spiny prominence distally as on first endopodal segment, a proximal row of spinules on same margin, and terminal patch of spinules on lateral surface.

Mandible ( Fig. 3C, D View FIG ) with toothed gnathobase; palp biramous; basis with one inner seta and two rows of setules; endopod two-segmented, setal formula 3, 6; exopod four-segmented, setal formula 1, 1, 1, 2; one seta on distal segment with patch of setules on tip.

Maxillule ( Fig. 4A, B View FIG ): praecoxal arthrite with 12 setae; coxal epipodite with two unequal setae, coxal endite with one seta; basis with two endites, proximal endite with three setae, distal endite with two setae; endopod one-segmented with seven setae; exopod one-segmented, with four setae; one seta shorter than others and ornament- ed with patch of spinules on tip.

Maxilla ( Fig. 4C View FIG ) with praecoxa separated from coxa by arthrodial membrane posteriorly only and with two endites, proximal with four setae, distal with one seta; coxa with two endites, each with three setae; basis produced into claw, with one seta; endopod three-segmented, first segment with four setae; second and third segments with total of six setae.

Maxilliped ( Fig. 4E View FIG ) with praecoxa and coxa separated by arthrodial membrane on both sides. Praecoxa with two endites armed with one and three setae; coxa and basis with two setae each; coxa with row of long setules along outer margin, basis with small distal row of spinules along outer and two others on surface of segment; row of long setules on internal margin; endopod foursegmented, setal formula 0, 0, 1, 4.

Swimming legs 1-4 biramous ( Figs 5 View FIG ; 6A, B View FIG ), with three-segmented rami; spine and setal formula: see Table 1.

Formula of spines of exopods: 4, 4, 4, 3. Formula of setae of exopods: 4, 5, 5, 5.

Leg 1 with one seta on second segment of endopod.

Leg 4 with setae on second endopodal segment and proximal inner seta on third ( Fig. 6B View FIG ) particularly strong.

Leg 5 ( Fig. 6C View FIG ) connected by narrow intercoxal plate; undivided protopod with outer seta and setules along inner margin; exopod one-segmented, armed distally with two spines and one long median seta; inner margin of protopod bearing short, stout, digitiform segment-like structure, with or without ornamenatation of spinules, interpreted as representing endopod.

Leg 6 ( Fig. 1E View FIG ) located laterally on genital double-somite, with three unequal setae, one small; longest seta, located more posteriorly, strong, curved dorsally.

Allotype male

Differing from female as follows:

Body ( Fig. 7A, B View FIG ): total length, excluding caudal setae 0.65 mm, greatest width 0.23 mm. Urosome six-segmented; genital and first abdominal somites separate ( Fig. 7 D View FIG ). Caudal rami ( Fig. 7A, E View FIG ) with few spinules on each side of ventral distal margin. Rostrum and labrum with anterior outgrowth (shown in lateral view in Figure 7C View FIG ).

Antennule (Fig. 8A, B) indistinctly 17-segment- ed, fifth, sixth, seventh segments incompletely divided. Setation formula as follows: 3, 5, 3, 2, 2, 2, 2, 1, 3, 2, 2, 2+a, 1, 2, 4, 2+a, 11+a; segmental homologies as: I-II, III-V, VI-VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX- XX, XXI-XXIII, XXIV-XXVIII.

Leg 1 (Fig. 8C): distal segments of right endopod fused partially.

Leg 5 ( Fig. 7F View FIG ): without endopod, one-segment- ed exopod with two internal setae, not present in female.

Leg 6 ( Fig. 7D View FIG ) with three setae, outermost longest, innermost very short, as small spine, median seta bearing a few (one on allotype) setules.

Variation: dissected paratypes (six females, four males, six copepodid stages)

From the six female paratypes, three have leg 5 of general shape (as in Figure 6D View FIG ); in these specimens, the endopodal structure varies in size and proportion; the endopodal structure, when present, is not always symmetrical on right and left legs. In addition, it can be present on one side only. No muscle connected to the presumed endopod has been found within protopod. The three other paratypes have a leg 5 lacking the endopod-like structure (Fig. 8G, H).

In one adult male, leg 1 does not show any fusion of the distal endopodal segments, as it is the condition in the allotype. Leg 5 lacks the endopod, as in the allotype. Leg 5 of the three other paratype males lacks the endopodal structure, as in the allotype male.

Female copepodid stage V: leg 5 as in Figure 8E. Male copepodid stage V: leg 5 as in Figure 8D. Copepodid stage IV (four specimens): leg 5 as in Figure 8F.