Stygepactophanes jurassicus Moeschler & Rouch, 1984

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 : 74-78

Stygepactophanes jurassicus Moeschler & Rouch, 1984 Figures 6, 7

Material examined.

♀ labeled as “holotype” collected from "source de la Doux à Delémont” (Jura, Switzerland), 1 ♂ from "Galerie de la captage de Champ-du-Moulin", Gorges de l’Areuse ( Neufchâtel, Switzerland) without type indication; each specimen dissected with the parts mounted in glycerine. Material deposited at the Department of Arthropodology and Entomology of the Museum of Natural History of Geneva (Switzerland). The type material consists of a slide with the dissected female holotype and a slide with a dissected male; the latter without status indication and labeled to be obtained in the "Galerie de la captage de Champ-du-Moulin". The mounts are of poor quality and many appendages appear to be absent or lost. The other specimens mentioned by Moeschler and Rouch (1984) (i.e., 2 ♂ - including 1 ♂ paratype and 1 copepodid) are missing. They seem absent in the Rouch collection and hosted at the Muséum national d’Histoire Naturelle de Paris and are certainly not present in the Genève Museum (F Fiers, pers. obs.). Fortunately, the original description by Moeschler and Rouch (1984) is detailed. The present contribution is a slight emendation of the original description, focussing on the finer morphological details, and aimed at analysing the status of the male specimen kept in Genève.

Supplementary description.

Female. Urosome (Fig. 6A) without P5, urosomite I unornamented; genital double-somite short, length/width ratio: 0.73, with small receptacle orifices and wide, bell-shaped copulatory funnel and wide copulatory pore. Posterodorsal and posterolateral margins smooth; posteroventral margin with six sets of spinules of different lengths; hyaline frill absent; urosomites IV and V ornamented with six groups of spinules on posteroventral margins. Anal somite as long as preceding one, with smooth free margin of anal operculum; anal sinus not covered by operculum, smooth except for few hairs along anal orifice. Posterodorsal and posterolateral margins smooth, posteroventral margin with spinules, either long or short.

Caudal rami (Fig. 6A, C): cylindrical, only slightly enlarged at proximal part and truncate at distal part, anterolateral accessory seta (I) absent; anterolateral seta (II) inserted on distal third of caudal ramus, with some minute spinules at insertion; posterolateral seta (III) broken, accompanied by two long spinules at insertion; outer and inner terminal setae ( IV–V) fused at base, both sparsely serrate and without breaking planes (Fig. 6A, B); basal part of inner terminal seta slightly inflated with narrow hyaline outer and inner membranes (outer membrane arrowed in Fig. 6A); terminal accessory seta (VI) ca. as long as half caudal rami; posteroventral margins of caudal rami with three long spinules; dorsal seta (VII) inserted at second third of caudal rami, near inner margin, articulated on basal part, and accompanied by one or two long spinules at insertion.

Antenna: with short coxa, half as long as wide, unornamented; spinules on abexopodal margin long, reaching distal fourth of allobasis; exopod with one seta, sparsely serrate along one side; endopod with distal margin bearing four elements (one spine and three setae).

P1-P4 armature as in Table 2. P3 (Fig. 7B, C): praecoxa, coxa and intercoxal sclerite well developed, unarmed and unornamented; basis with outer seta and cluster of spinules near articulation with exopod; outer elements of exopod pectinate; frontal surface of exopodal segment 3 with large subapical cuticular pore (Fig. 7C); outer element on endopod spiniform, inner one setiform.

P5 absent.

P6 (Fig. 6A): reduced, represented by a single (smooth?) long seta, and confluent midventrally forming a caudally expanded convex plate covering anterior part of genital field.

Male. Urosome (Fig. 6C): urosomite I without P5, unornamented (Fig. 7G); urosomites II–V ornamented (urosomites III–V as in female, and urosomite II ornamented as urosomites III–V); outer terminal and inner terminal setae ( IV–V) of caudal rami fused at base; seta V not inflated and lacking hyaline membranes; dorsal seta (VII) inserted near or on inner margin of caudal rami.

P 1 (Fig. 7A): praecoxa, coxa and intercoxal sclerite unarmed and unornamented; intercoxal sclerite narrow and wide; medial margin of exopodal segments 2 and 3 with sparse hairy ornament; outer margins of exopodal segments with few spinules; armature elements of inner margin and inner distal margin delicately serrate outwardly, plumose midway inwardly; endopodal segment 1 without spinule ornament, endopodal segment 2 with spinules along distal margin; outer terminal element on endopodal segment 2 claw-shaped (falcate), serrate along outer margin; inner element robust with spinular appearance, outwardly serrate, plumose midway inwardly, and at least twice as long as outer element; left and right legs identical.

P3 (Fig. 7D, E) with well-developed praecoxa, coxa and intercoxal sclerite, all unarmed and unornamented; basis as in female; medial armature element on exopodal segment 3, segment more robust than in female; outer spine on exopodal segment 3 robust, claw-shaped and strongly serrate in middle of outer margin; apical margin with long median spinule and wide subapical pore on frontal surface (Fig. 7E); endopod 2-segmented; proximal segment twice as long as wide, with medial distal corner forming a truncate expansion; distal segment globular and extended into two equally long sharp apophyses overreaching exopod.

P4 (Fig. 7F) with well-developed praecoxa and coxa; intercoxal sclerite unarmed and unornamented; basis without outer seta and with short row of spinules near outer margin; medial element on exopodal segment 3 with distal inner margin pectinate; endopod 1-segmented, twice as long as wide, with outer terminal element spiniform and inner one setiform.

P5 absent.

P6 (Fig. 6C) represented as a caudally symmetrical bilobate plate, without setae and completely smooth.

Moeschler and Rouch (1984) reported the aberrant nature of the exopodal armature of P1 in the male specimen collected at the "Captage de Champ-du-Moulin". They provided an illustration ( Moeschler and Rouch (1984): fig. 7b, page 968) of a leg with two spines on exopodal segment 2, and only three armature elements on its terminal segment. The opposite leg was mentioned as being armed in the same way as described for the female holotype with one outer spine on exopodal segment 2 and four elements on the terminal segment.

Re-examination of the slide kept at Genève labeled: "Galerie de la Captage de Champ-du-Moulin, Gorges de l’Areuse (NE); 17.11.1981" revealed, however, that both legs are identical, and resemble the female P1 as illustrated in Moeschler and Rouch (1984): fig. 5a, page 965. This observation confirms that the male paratype deposited at Genève must have been mislabeled during processing of the slides.