Nesticus kosodensis Yaginuma, 1972

Suzuki, Yuya & Ballarin, Francesco, 2020, Nesticus kosodensis Yaginuma, 1972 bona species. Molecular and morphological separation from N. latiscapus Yaginuma, 1972 with notes on cave scaffold-web spiders subspecies in Japan (Araneae, Nesticidae), Subterranean Biology 35, pp. 79-96: 82-86

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Nesticus kosodensis Yaginuma, 1972

stat. nov.

Nesticus kosodensis Yaginuma, 1972   stat. nov. Figures 1a-c View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 8a, b View Figure 8

Nesticus latiscapus kosodensis   Yaginuma, 1972: 295, f. 20-23 (♂♀).

N. latiscapus kosodensis   Yaginuma, 1977: 315, pl. 2, f. 4 (♂).

N. latiscapus kosodensis   Yaginuma, 1979: 265, pl. 7, f. 2, 4 (♂♀).1

Material examined.

Holotype. Japan - Honshu Island • ♂; Yamanshi Prefecture, Kitatsuru-gun, Tabayama-mura, Kosode Limestone Cave (小袖鍾乳洞); [35.7938N, 138.9722E]; 3 Feb. 1969, Akama H. leg.; NSMT-Ar 70 (as N. latiscapus kosodensis   ).

Paratype. Japan - Honshu Island • 1♀; same data as the holoype; NSMT-Ar 71 (as N. latiscapus kosodensis   ).

Other material.

Japan - Honshu Island • 4♂♂, 3♀♀; Kitatsuru-gun, Kosuge-mura, Hashitate, Odaki (雄滝); 35.74476N, 138.88462E; 10 Nov. 2019, Suzuki Y. leg.; under stones; YSPC, FBPC • 4♀♀; Tokyo Prefecture, Nishitama-gun, Okutama-machi, Nippara, Nippara Limestone Cave (日原鍾乳洞); 35.8524N, 139.0407E; Ballarin F. leg.; FBPC.


Species closely related to Nesticus latiscapus   , but both sexes can be distinguished by the morphology of the genitalia. Male N. kosodensis   stat. nov. can be separated from male N. latiscapus   by the following combination of characters: Dp2 and Dp3 close to each other (separated from each other in N. latiscapus   , see Fig. 3b View Figure 3 vs. 6b); Di narrower, lacking a serrated edge (Di wider and bearing a serrated edge in N. latiscapus   , see Fig. 3d View Figure 3 vs. 6d); Ma weakly protruding (Ma strongly protruding in N. latiscapus   , see Fig. 3e View Figure 3 vs. 6e); Be present (Be absent in N. latiscapus   , see Fig. 3a, b View Figure 3 vs. 6a, b); Ta weakly developed but present (lacking in N. latiscapus   , see Fig. 3a, e View Figure 3 vs. 6a, e). Females N. kosodensis   stat. nov. are distinguished from females N. latiscapus   by the different shape of scapus, narrower towards the tip and with convergent edges in N. kosodensis   stat. nov., almost of the same width or slightly wider towards the tip, with slightly divergent edges and lobate corners in N. latiscapus   (Fig. 4 View Figure 4 vs. Fig. 7 View Figure 7 ). The shape of copulatory openings is also different between the two species: the edge of the opening is curved and slanted compared to the edge of the scapus in N. kosodensis   stat. nov., but straight and parallel to the edge of the scapus in N. latiscapus   (Fig. 4 View Figure 4 vs. Fig. 7 View Figure 7 ).


Male. Total length: 4.00-4.29, carapace: 1.77-2.01 long, 1.04-1.75 wide (based on three males).

Habitus as in Fig. 1a, b View Figure 1 . Carapace light yellowish brown, midline and lateral edges darker. Chelicera, labium and sternum light yellowish-brown without any markings. Legs yellowish-brown with dark bands. Leg measurements as follows (based on one male): I 15.60 (4.34, 0.83, 4.62, 4.21, 1.61), II 12.10 (3.48, 0.77, 3.32, 3.18, 1.34), III 8.55 (2.60, 0.58, 2.25, 2.14, 0.98), IV 11.70 (3.68, 0.70, 3.09, 2.97, 1.25). Dorsum of abdomen whitish-yellow with narrowly spaced pairs of black markings posteriorly.

Palp as in Figs 2 View Figure 2 , 3 View Figure 3 , 8a View Figure 8 . Paracymbium with five processes: ventral process recurved, dorsal process 1 sharp and weakly curved when the palp is observed ventrally and laterally, dorsal process 2 short and straight, dorsal process 3 very small and close to the basal part of dorsal process 2, hidden behind ventral process when the palp is observed ventrally. All dorsal processes strongly sclerotized. Distal process of paracymbium sharp with a smooth edge. Embolus with a well-developed bulge, median apophysis weakly protruded, tegular apophysis small and triangular.

Female. Total length: 3.73-3.90, carapace: 1.61-1.73 long, 1.46-1.47 wide (based on two females).

Habitus as in Fig. 1c View Figure 1 . Color and markings as in the male. Legs measurements as following (based on one female): I 12.80 (3.76, 0.71, 3.53, 3.30, 1.48), II 9.57 (2.77, 0.69, 2.55, 2.40, 1.16), III 6.34 (1.96, 0.58, 1.62, 1.38, 0.80), IV 9.51 (3.03, 0.67, 2.48, 2.27, 1.06).

Epigyne and vulva as in Figs 4 View Figure 4 , 8b View Figure 8 . Scapus prolonged posteriorly, narrower towards the tip, with slightly convergent edges and bearing a U-shaped groove. Edge of copulatory openings rounded and slanted compared to the edge of the scapus. Insemination and fertilization ducts reaching spermathecae with a short and convoluted trait. Spermathecae oval. Vulval pockets strongly wrinkled, located above spermathecae.


Endemic to central Honshu, Japan (Yamanashi and Tokyo Prefectures). See Fig. 10 View Figure 10 .














Nesticus kosodensis Yaginuma, 1972

Suzuki, Yuya & Ballarin, Francesco 2020

Nesticus latiscapus kosodensis

Yaginuma 1972