Leiocanthus satanicus, Cepeda & Sánchez & Sørensen & Landers, 2022

Cepeda, Diego, Sánchez, Nuria, Sørensen, Martin V. & Landers, Stephen C., 2022, Leiocanthus quinquenudus sp. nov. and L. satanicus sp. nov., two new species of pycnophyid Kinorhyncha (Allomalorhagida: Pycnophyidae) from the Gulf of Mexico, Zootaxa 5093 (3), pp. 315-336 : 325-328

publication ID	https://doi.org/ 10.11646/zootaxa.5093.3.3
publication LSID	lsid:zoobank.org:pub:0A4DE130-B44E-4526-8752-DFB6E60DDFA5
DOI	https://doi.org/10.5281/zenodo.5910867
persistent identifier	https://treatment.plazi.org/id/CA784956-9774-FF93-FF54-00AEFBCCF83A
treatment provided by	Plazi
scientific name	Leiocanthus satanicus
status	sp. nov.

Treatment

Leiocanthus satanicus View in CoL sp. nov.

Zoobank code: urn:lsid:zoobank.org:act:9B48A215-F9C4-4BE2-8D5A-D650133B133

( Figs. 5–8 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Synonymy

Pycnophyes sp. A —Landers et al. 2018: Table 2.

Leiocanthus W View in CoL —in Landers et al. 2019: p. 5.

Material examined. Holotype, adult female, collected on November 12, 2013 at St. 68-2013 in the northern Gulf of Mexico continental shelf: 29.2998° N, 88.7200°W ( Table 1 View TABLE 1 ) at 59 m depth; mounted in Fluoromount G ®, deposited at the NHMD under catalogue number: NHMD-915202 GoogleMaps . Paratypes, three adult males and six adult females, one of the females collected at the same station as the holotype, remaining specimens collected at different stations ( Table 1 View TABLE 1 ), mounted in Fluoromount G ® and deposited at NHMD under catalogue numbers: NHMD-915203–915211. Two additional specimens, one male and one female, mounted for SEM and deposited in the personal reference collections of SCL and MVS .

Diagnosis. Leiocanthus with middorsal cuticular elevations on segments 1–6. Unpaired paradorsal setae on segments 4 and 6; paired setae in subdorsal position on segments 2, 4, 6 and 8, in laterodorsal position on segments 3, 5, 7 and 9, paralateral position on segment 1, lateroventral position on segments 2, 4, 6, 8 and 10 (two pairs in the latter), ventrolateral position on segments 1 and 5, ventromedial position on segments 4–7 and 9, and paraventral position on segments 3 and 8. Males with sexually dimorphic ventromedial tubes on segment 2, females with setae instead. Lateral terminal spines absent, minute and bulbous protuberances instead. Anterolateral margins of the tergal plate of segment 1 extended into horn-like, medially recurved, distally pointed projections; anterior margin of tergal plate strongly denticulated, posteriorly followed by a crenulated area; cuticular wrinkles at the central region of the tergal plate.

Etymology. The specific epithet of the species refers to the Latin name Satâna, derived from the Hebraic הַשָּׂטָן (ha-shatán), which is a negative entity of the Abrahamic religions that seduces humanity to commit sin. Satan has been traditionally represented in graphic and literary arts as a fallen angel with conspicuous horns, which resembles the recurved anterolateral margins of the segment 1 tergal plate of the new species.

Description. See Table 4 View TABLE 4 for measurements and dimensions and Table 5 View TABLE 5 for summary of seta, tube, glandular cell outlet, and sensory spot positions.

Head. Only two specimens had the head everted, hence exact details on the morphology and arrangement of the mouth cone and introvert structures cannot be completely provided. Internal rings of mouth cone not observed. Ring 00 of mouth cone with nine, equally sized outer oral styles, each one composed of a single, flexible unit, wider at the base, bearing a fringed basal sheath, with a lateral incision about one third from the proximal end, progressively tapering towards a distally rounded tip ( Fig. 6C View FIGURE 6 ). Outer oral styles located anterior to each introvert sector, except in the middorsal sector 6 where a style is missing.

Introvert with six transverse rings of scalids and 10 longitudinal sectors defined by the position of the primary spinoscalids. Ring 01 with 10 primary spinoscalids, larger than the remaining ones, each one composed of a basal, rectangular, wide sheath and a distal, elongated, flexible, laterally compressed, distally rounded end-piece ( Fig. 6D, F View FIGURE 6 ). Basal sheath of primary spinoscalids superficially fringed, bearing a rhomboid cuticular piece superficially fringed near the articulation point with the end-piece ( Fig. 6D View FIGURE 6 inset, F). Rings 02–06 with several regular-sized scalids, conspicuously smaller than the primary spinoscalids, also composed of a basal, rectangular, superficially fringed, wide sheath and a distal, elongated, flexible, distally rounded end–piece ( Fig. 6F View FIGURE 6 ). Exact arrangement of regular-sized scalids cannot be provided due to the collapsed condition of the only available introverts. Despite this, the odd-numbered sectors seem to possess seven regular-sized scalids arranged as a double diamond ( Fig. 6F View FIGURE 6 ). A ring of 14 trichoscalids posterior to the scalid rings ( Fig. 6E View FIGURE 6 ), arranged as two in the odd-numbered sectors (except sector 1 with a single trichoscalid) and one in the even-numbered sectors of the introvert.

Neck. Neck with four dorsal and two ventral sclerotized placids ( Figs. 5A–B View FIGURE 5 , 6G–H View FIGURE 6 ). Mesial dorsal placids sub-quadrangular, conspicuously higher than lateral ones ( Figs. 5B View FIGURE 5 , 6G View FIGURE 6 ), ca. 33–41 μm wide at the base; lateral dorsal placids rectangular ( Figs. 5B View FIGURE 5 , 6G View FIGURE 6 ), ca. 23–26 μm wide at the base. Ventral placids even more rectangular, longitudinally compressed, with the posterolateral margins straight to slightly curved towards the sternal plates of the first trunk segment ( Figs. 5A View FIGURE 5 , 6H View FIGURE 6 ), ca. 21–30 μm wide at the base.

Trunk. Trunk rectangular, stout, triangular in cross–section, composed of 11 segments ( Figs. 5A–B View FIGURE 5 , 6A–B View FIGURE 6 , 8A View FIGURE 8 ). Segment 1 with one tergal, two episternal, and one midsternal plates; remaining segments with one tergal and two sternal plates ( Figs. 5A–D View FIGURE 5 , 6A–B View FIGURE 6 , 7A–K View FIGURE 7 , 8A–F View FIGURE 8 ). Maximum sternal width at segment 3 ( Table 4 View TABLE 4 ), almost constant in width throughout the trunk until segment 3, and progressively tapering along the last trunk segments ( Figs. 5A–B View FIGURE 5 , 6A–B View FIGURE 6 , 8A View FIGURE 8 ). Sternal cuticular plates relatively narrow in relation to trunk length (MSW–3:TL interval ratio = 21.8–26.8) ( Table 4 View TABLE 4 ), giving the animal a relatively slender appearance ( Figs. 5A–B View FIGURE 5 , 6A–B View FIGURE 6 , 8A View FIGURE 8 ). Segments 1–11 with glandular cell outlets with a single round to oval opening: segments 1 and 9–10 with these glandular cell outlets in subdorsal and ventromedial positions, segments 2–8 in subdorsal and paraventral positions, and segment 11 in subdorsal position ( Figs. 5A–D View FIGURE 5 , 7A–J View FIGURE 7 ); intraspecific variation of this character was found in a couple of specimens that showed up to three round openings per glandular outlet ( Fig. 7D View FIGURE 7 ); in addition, in some specimens the bilateral pattern was lost as the glandular cell outlet was missing in one side of some tergal plates. Segments 2–10 with paired, small, not always conspicuous cuticular ridges in ventrolateral position, with adjacent, minute glandular cell outlets ( Fig. 5A–D View FIGURE 5 ). Minute, acicular cuticular hairs, widely covering the cuticular surface of segments 1–10 (except the most anterior halves of the episternal plates of segment 1 where hairs are absent), denser at the tergosternal junctions ( Fig. 8B–F View FIGURE 8 ). Males with sexually dimorphic longitudinal bands of cuticle densely covered by smaller acicular hairs in ventromedial position of segment 2, under the tubes ( Fig. 8C View FIGURE 8 ). Very conspicuous, rounded to oval muscular scars without hair-covering in laterodorsal and ventromedial positions ( Figs. 5A–D View FIGURE 5 , 7A–J View FIGURE 7 ). Pachycycli and ball-andsocket joints well-developed and thick on segments 2–10 ( Figs. 5A–D View FIGURE 5 , 7A–H View FIGURE 7 ). Apodemes absent. Posterior margin of segments straight, with primary pectinate fringes showing weakly serrated free flaps ( Figs. 5A–D View FIGURE 5 , 7A–H View FIGURE 7 , 8A–F View FIGURE 8 ). Secondary pectinate fringes as three (dorsal) to two (ventral) transverse rows, finely serrated, becoming wavier at the sternal plates, extending posteriorly in triangular extensions near the location of the muscular scars ( Figs. 5A–D View FIGURE 5 , 8C, E, F View FIGURE 8 ).

Segment 1 with middorsal elevation not projecting beyond the posterior margin of segment, with conspicuous paradorsal, butterfly-like atria of sensory spots ( Figs. 5B View FIGURE 5 , 7A View FIGURE 7 ). Anterolateral margins of the tergal plate forming conspicuous horn-like, medially recurved, distally pointed projections ( Figs. 5A–B View FIGURE 5 , 6A–B, I View FIGURE 6 , 8A–B View FIGURE 8 ). Anterior margin of tergal plate strongly denticulated, posteriorly followed by a crenulated area ( Figs. 5B View FIGURE 5 , 6K View FIGURE 6 ). Anterior margins of sternal plates with several, small, cuticular depressions and some semi-circular ridges ( Figs. 5A View FIGURE 5 , 6H View FIGURE 6 ). Characteristic cuticular wrinkles at the central region of the tergal plate in subdorsal towards laterodorsal position ( Figs. 5B View FIGURE 5 , 6K View FIGURE 6 ). Midsternal plate almost rectangular, not extended at its base, with a small lateral indentation near its anterior margin, and a straight posterior margin ( Figs. 5A View FIGURE 5 , 6B View FIGURE 6 , 8A View FIGURE 8 ). Paired setae in paralateral and ventrolateral positions ( Figs. 5A–B View FIGURE 5 , 7A View FIGURE 7 , 8B View FIGURE 8 ). Sensory spots in paradorsal (one pair), subdorsal (two pairs, longitudinally aligned), laterodorsal (one pair), paralateral (one pair), ventrolateral (one pair) and ventromedial (one pair) positions ( Figs. 5A–B View FIGURE 5 , 7A View FIGURE 7 , 8B View FIGURE 8 ). Sensory spots on this and remaining segments oval, with up to three pores surrounded by several rings of micropapillae.

Segment 2 with middorsal elevation as on the preceding segment ( Figs. 5B View FIGURE 5 , 7D View FIGURE 7 ). Paired setae in subdorsal and lateroventral positions; subdorsal setae more mesial than subdorsal sensory spots; ventromedial setae only in females (sexually dimorphic) and located more lateral than the ventromedial sensory spots ( Figs. 5 View FIGURE 5 A-C, 7B, D). Sensory spots in paradorsal (one pair), subdorsal (two pairs), laterodorsal (one pair) and ventromedial (one pair) positions ( Figs. 5A–C View FIGURE 5 , 7B, D View FIGURE 7 , 8C View FIGURE 8 ). Males with conspicuously large, sexually dimorphic tubes in ventromedial position ( Figs. 5A View FIGURE 5 , 8C View FIGURE 8 ).

Segment 3 with middorsal elevation as on the preceding segments ( Figs. 5B View FIGURE 5 , 7D View FIGURE 7 ). Paired setae in laterodorsal and paraventral positions ( Figs. 5A–B View FIGURE 5 , 7C–D View FIGURE 7 , 8C View FIGURE 8 ). Sensory spots in paradorsal (one pair), subdorsal (two pairs), laterodorsal (one pair) and ventromedial (one pair) positions ( Figs. 5A–B View FIGURE 5 , 7C–D View FIGURE 7 , 8C View FIGURE 8 ). Intraspecific variation in the arrangement of the laterodorsal setae has been observed in two specimens, where these structures were laterally displaced, still in laterodorsal position but more lateral than the laterodorsal sensory spots.

Segment 4 with middorsal elevation as on the preceding segments ( Fig. 5B View FIGURE 5 ). Unpaired seta in paradorsal position, and paired setae in subdorsal, lateroventral and ventromedial positions; subdorsal setae flanked by the two pairs of subdorsal sensory spots, ventromedial setae more mesial than those of female segment 2 ( Figs. 5A–B View FIGURE 5 , 7C View FIGURE 7 , 8D View FIGURE 8 ). Sensory spots in paradorsal (one pair), subdorsal (two pairs), laterodorsal (one pair) and ventromedial (one pair) positions ( Figs. 5A–B View FIGURE 5 , 7C View FIGURE 7 , 8D View FIGURE 8 ).

Segment 5 with middorsal elevation as on the preceding segments ( Figs. 5B View FIGURE 5 , 7F View FIGURE 7 ). Paired setae in laterodorsal, ventrolateral and ventromedial positions; ventromedial setae more lateral than those of segment 4 (not aligned longitudinally) ( Figs. 5A–B View FIGURE 5 , 7E–F View FIGURE 7 , 8D View FIGURE 8 ). Sensory spots in paradorsal (one pair), subdorsal (two pairs), laterodorsal (one pair) and ventromedial (one pair) positions ( Figs. 5A–B View FIGURE 5 , 7E–F View FIGURE 7 , 8D View FIGURE 8 ); the latter pair aligned with that of segment 3. Intraspecific variation in the arrangement of the laterodorsal setae has been observed in a single specimen, where these structures were laterally displaced, still in laterodorsal position but more lateral than the laterodorsal sensory spots.

Segment 6 with middorsal elevation as on the preceding segments ( Figs. 5B View FIGURE 5 , 7H View FIGURE 7 ). Unpaired seta in paradorsal position, and paired setae in subdorsal, lateroventral and ventromedial positions (the former flanked by the subdorsal sensory spots, the latter longitudinally aligned with those of segment 4) ( Figs. 5A–B View FIGURE 5 , 7H View FIGURE 7 ); deviations from the bilateral symmetry in the position of the ventromedial setae has been observed in a single specimen that had one seta mesially displaced, though still in ventromedial position. Sensory spots in paradorsal (one pair), subdorsal (two pairs), laterodorsal (one pair) and ventromedial (one pair) positions ( Figs. 5A–B View FIGURE 5 , 7H View FIGURE 7 ); the latter pair aligned with that of segment 4.

Segment 7 without middorsal process or elevation. Paired setae in laterodorsal and ventromedial positions, the laterodorsal ones more lateral than the laterodorsal sensory spots, and the ventromedial ones aligned with those of segment 5 and female segment 2 ( Figs. 5A–B View FIGURE 5 , 7H View FIGURE 7 ). Sensory spots in subdorsal (two pairs), laterodorsal (one pair) and ventromedial (one pair) positions ( Figs. 5A–B View FIGURE 5 , 7H View FIGURE 7 ); the latter pair aligned with that of segment 3. Intraspecific variation in the arrangement of the laterodorsal setae has been observed in a single specimen, where these structures were mesially displaced, still in laterodorsal position but more mesial than the laterodorsal sensory spots.

Segment 8 without middorsal process or elevation. Paired setae in subdorsal, lateroventral and paraventral positions; the former flanked by the subdorsal sensory spots ( Figs. 5A–B View FIGURE 5 , 7G View FIGURE 7 , 8E View FIGURE 8 ). Deviations from the bilateral pattern in the arrangement of the paraventral setae has been observed in a single specimen, which had the left sternal plate with the seta in ventromedial instead of paraventral position. Sensory spots in subdorsal (three pairs), laterodorsal (one pair) and ventromedial (one pair) positions ( Figs. 5A–B View FIGURE 5 , 7G View FIGURE 7 , 8E View FIGURE 8 ); the latter pair aligned with that of the preceding segment.

Segment 9 without middorsal process or elevation. Paired setae in laterodorsal and ventromedial position; the latter longitudinally aligned with those of segments 5 and 7 ( Figs. 5A–B View FIGURE 5 , 7I–J View FIGURE 7 , 8E View FIGURE 8 ). Sensory spots in subdorsal (three pairs), laterodorsal (one pair), ventrolateral (one pair) and ventromedial positions ( Figs. 5A–B View FIGURE 5 , 7I–J View FIGURE 7 , 8E, H View FIGURE 8 ). Nephridia externally opening as short cuticular tubes with fringed tips ( Fig. 5A View FIGURE 5 ).

Segment 10 without middorsal process or elevation. Tergal plates with elongated, dagger-like projections at midlateral posterior margins ( Figs. 5A–B, D View FIGURE 5 , 6A–B, J View FIGURE 6 , 8A, F View FIGURE 8 ). Two pairs of setae in lateroventral position ( Figs. 5A–B, D View FIGURE 5 , 8F View FIGURE 8 ). One pair of sensory spots in subdorsal, laterodorsal, ventrolateral and ventromedial positions ( Figs. 5A–B, D View FIGURE 5 , 8F View FIGURE 8 ).

Segment 11 with one pair of type 3 sensory spots in subdorsal position ( Figs. 5B View FIGURE 5 , 7K View FIGURE 7 ). Males with two pairs of sexually dimorphic penile spines and genital pores ( Figs. 5A View FIGURE 5 , 8F View FIGURE 8 ). Lateral terminal spines absent; minute, rectangular, distally rounded, bulbous protuberances emerge between tergal and sternal plates, in males superficially covered by hairs ( Figs. 5A, D View FIGURE 5 , 7K View FIGURE 7 ).