Stygepactophanes occitanus Galassi & Fiers

Galassi, Diana M. P., Fiers, Frank, ole-Olivier, Marie-Jose & Fiasca, Barbara, 2019, Discovery of a new species of the genus Stygepactophanes from a groundwater-fed spring in southern France (Crustacea, Copepoda, Harpacticoida, Canthocamptidae), ZooKeys 812, pp. 69-91 : 71-73

Stygepactophanes occitanus Galassi & Fiers sp. n. Figures 1, 2, 3, 4, 5

Material examined.

Holotype here designated. Adult ♀ completely dissected and mounted in polyvinyl lactophenol on one slide, coll. M.-J. Dole-Olivier and Dominique Martin, 21 July 2009, deposited at the Muséum national d’Histoire naturelle de Paris. Paratypes. 1 ♀, same data as holotype, preserved in alcohol, coll. M.-J. Dole-Olivier and Dominique Martin, 9/08/2010. Additional material: 3 ♀ copepodids collected at the Sanguinière spring system, from a spring mouth located at 2199 m above sea level.

Etymology.

The specific epithet refers to the region Occitania, derived from the Medieval Latin Occitania (from where the new species was collected, a region now encompassing the French administrative region Languedoc-Roussillon-Midi-Pyrénées which is located on part of the traditional Occitania and includes Roussillon).

Type locality.

Sanguinière spring system, Var Department, Mercantour National Park, France, Var river catchment at Entraunes municipality at 2040 m above sea level; coordinates 44.25226354N, 6.77111744E.

Diagnosis.

Stygepactophanes occitanus Galassi and Fiers, sp. n. has a well-developed P5, with rudimentary intercoxal sclerite, together with a falcate outer terminal claw of P1 endopod, antennal exopod bearing two elements, P4 endopod 1-segmented versus 2-segmented in P2-P3, P2-P4 exopodal segment 3 with five armature elements, P6 with three setae of different lengths, rounded anal operculum, bearing 3-4 strong spinules.

Description of the female.

Body (Fig. 1A, B) slender and cylindrical in dorsal view, with urosome slightly narrower than prosome. Body length of holotype 425 μm, female paratype 410 μm. Podoplean flexure indistinct; prosome and urosome of same length. Integument without pits and very feeble sclerotization. Integumental windows absent; female genital and first abdominal somites completely fused forming genital double-somite; double-somite short, length/width ratio: 0.45; genital field located near anterior margin of genital somite and extended far beyond proximal half of somite. Genital complex expanded caudally to end of second third of ventral surface (Fig. 2A), with rather large reniform orifices of receptacles and long copulatory duct; the latter with wide funnel and copulatory pore; slit shaped pore present on both sides of copulatory pore.

Body ornamentation: integument of cephalothorax and urosome unornamented in the paratype, with short lateral row of spinules on left side of P4-bearing somite in the holotype (Fig. 2C); P5-bearing somite either completely smooth (holotype) or with short row of spinules on left side (paratype) (Fig. 1A, B); integument of genital double-somite either unornamented (holotype) or with short posterodorsal row of spinules (paratype; Fig. 1A); posterolateral and posteroventral margins ornamented with slender spinules, short medially (Fig. 1B), absent medioventrally (Fig. 2A); posterior margins of urosomites IV and V lateroventrally and posteroventrally with narrow spinules, interrupted mid-ventrally on urosomite IV, continuous row of spinules on urosomite V (Fig. 2A). Posterodorsal hyaline frills of body somites narrow and straight, plain. Anal somite unornamented along posterodorsal and posterolateral margins; posteroventral margin with two sets of spinules medially; outer ones minute, inner ones long and slender; anal sinus smooth, anal orifice with few slender hairs (Fig. 2A). Anal somite as long as preceding one with convex anal operculum bearing four (holotype: Fig. 2D) or three (paratype: Fig. 1A) coarse spinules along distal margin; distal margin of operculum not extending beyond anal sinus.

Caudal rami (Fig. 1 A–C): conical and truncate, in both dorsal and lateral view, slightly divergent; length/width ratio: 2.75 (holotype) and 2.80 (paratype). Anterolateral accessory seta (I) minute, inserted on proximal third of caudal ramus, anterolateral seta (II) inserted on distal third of caudal ramus, accompanied by two or three long and slender spinules at insertion (Figs 1C, 2A), ca. 1.5 times longer than anterolateral accessory seta; posterolateral seta (III) slender and unornamented, outer terminal seta (IV) 1.5 times longer than ramus, sparsely serrate; inner terminal seta (V) (Fig. 2B) as long as the whole body, rather slender, sparsely serrate along outer margin (Fig. 2B); both setae IV and V without breaking plane; terminal accessory seta (VI) short, less than 1/3 length of caudal ramus; dorsal seta (VII) located at more than half of caudal ramus, near inner margin, articulating on a single basal section.

Rostrum (Figs 1A, 3A): triangular with tongue-shaped apex and apparently completely fused to cephalothorax; apex reaching just the first antennule segment; integument smooth; sensilla pair present, located subapically.

Antennule (Fig. 3A, B): rather short, backwards bent, reaching halfway along cephalothorax at most; 7-segmented, without particular integument ornamentation; armature (from proximal to distal segment): 1 –8-5–2+Aesth-1– 3-9+Aesth. Aesthetasc on segment IV rather wide, leaf shaped (but wrinkled in both specimens), overreaching segment VII, and fused at base with accompanying seta (acrothek); aesthetasc on segment VII slender and tongue-shaped, fused at base with terminal seta (acrothek).

Antenna (Fig. 3C): with allobasis and 1-segmented exopod; syncoxa robust, unornamented; allobasis cylindrical, 1.75 times longer than wide with two smooth setae and some slender spinules along abexopodal margin; terminal endopodal segment armed with nine elements: three lateral ones (two spines, one seta) and six distal ones (one spine, five setae); both outer distal ones fused at base; armature elements partially squamous and serrate; outer margin with two clusters of spinules; exopod located at proximal fourth of allobasis, 1-segmented and well developed, bearing one lateral and one terminal delicately serrate setae.

Mandible (Fig. 3D): rather slender, coxal gnathobase slender, without ornamentation; palp rudimentary bearing two short slender setae; cutting edge consisting of two strong bi-dentate oral and four-five multi-dentate aboral teeth.

Labrum (Fig. 3E): crescent with a subapical transverse row of spinules and an apical transverse row of setules; both edges with a short row of strong spinules.

Labium (Fig. 3F): with an oblique row of strong spinules on each side, free distal margin with setules; paragnaths armed distally with several clusters of fragile hair-like and slender spinulose elements.

Maxillule (Fig. 3G, H): well developed arthrite incorporated into praecoxa, with seven strong curved uni- or multi-serrate armature elements inserted on free distal margin, two long lateral setae and two anterior surface setae. Basis cylindrical with a total of seven elements: four naked setae on outer margin, three apical elements, one of which strong and falcate.

Maxilla (Fig. 3I): syncoxa with 2 well-developed endites that are not defined at their bases, distal endite with three setae, one serrate and two slender, bare setae; proximal endite with two setae, one bare and one serrate. Allobasis drawn out into strong unipinnate claw, rather slender, medial structure armed with widely spaced slender spinules, accompanied by one serrate and one smooth setae; endopod rudimentary, represented by two smooth setae.

Maxilliped (Figs 3J, 5A): subchelate; syncoxa short, rather quadrangular, ornamented with short rows of spinules, but lacking armature elements; basis very long (length/width ratio: 3.4) with a short row of spinules at the middle of anterior and posterior surfaces; endopod 1-segmented, extended in a long sparsely ornamented claw.

P1 (Figs 2F, 5B): prehensile; well-developed praecoxa, coxa, basis and wide intercoxal sclerite; 3-segmented exopod and 2-segmented endopod; exopod and endopod subequal in length; endopodal segment 1 quite overreaching exopodal segments 1 and 2; praecoxa and intercoxal sclerite spineless; coxa with short rows of small spinules on frontal and caudal surfaces; basis with a row of coarse spinules near articulation of each ramus, on frontal side, and near insertion of inner seta; outer seta on basis short, robust, sparsely pinnate; inner seta, bent outwards, reaching halfway along endopod 1, spiniform, serrate along outer margin only; exopod segments with coarse spinules near distal outer corner, slender spinules near insertion of inner armature elements on second and third segments; endopod with spinules along outer margin of first segment and near insertion of armature elements on second segment; armature elements of exopod serrate along outer margin only; outer terminal seta on endopodal segment 2 robust, claw-shaped, serrate midway of outer margin; inner seta geniculate, slightly serrate; armature formula as in Table 1.

P2-P4 (Figs 4A, B, D; 5C): well-developed praecoxa, coxa, intercoxal sclerite and basis; P2-P3 with 3-segmented exopods and 2-segmented endopods, P4 with 1-segmented endopod; praecoxa and intercoxal sclerite spineless, coxa and basis with short rows of spinules on anterior surface, and spineless on caudal surface; exopodal segments with coarse spinules on outer distal edge and naked inner margin except for two hair-like elements on second segment of P2 and P3; P2-P3 endopod 1 quadrate, unarmed, and spineless; P2-P3 endopodal segment 2 ca. three times longer than wide, with two or three coarse spinules along outer margin; inner margin bare; P4 endopod small, rectangular, 2.5 times longer than wide, not reaching the middle of exopodal segment 1, and unornamented; armature formula of P1-P4 exopods and endopods as in Table 1.

P5 (Figs 4E, 5D): baseoendopod and exopod not fused; baseoendopod with short inner lobe, not reaching the middle of exopod, and with short spiniform setae; left lobe with two apical and one medial setae, right lobe with two apical setae; intercoxal sclerite present, spineless; basipodal outer seta slender and short, sparsely pinnate, accompanied by cluster of spinules at insertion; exopod semi-rectangular, 1.5 times longer than wide, with five robust sparsely serrate setae: three outer, one apical, one medial; apical and medial setae the longest.

P6 (Fig. 2A, E): remnants fused, symmetrical, bearing three small setae; medial and middle setae minute and smooth, outer seta four times longer than the inner ones, robust and serrate along medial margin; legs fused medially forming a genital operculum.

Male.

Unknown.