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-cView Figure 1, 2View Figure 2, 3View Figure 3, 4View Figure 4, 8a, bView 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. 3bView Figure 3 vs. 6b); Di narrower, lacking a serrated edge (Di wider and bearing a serrated edge in N. latiscapus  , see Fig. 3dView Figure 3 vs. 6d); Ma weakly protruding (Ma strongly protruding in N. latiscapus  , see Fig. 3eView Figure 3 vs. 6e); Be present (Be absent in N. latiscapus  , see Fig. 3a, bView Figure 3 vs. 6a, b); Ta weakly developed but present (lacking in N. latiscapus  , see Fig. 3a, eView 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. 4View Figure 4 vs. Fig. 7View 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. 4View Figure 4 vs. Fig. 7View 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, bView 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 2View Figure 2, 3View Figure 3, 8aView 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. 1cView 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 4View Figure 4, 8bView 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. 10View Figure 10.














Nesticus kosodensis Yaginuma, 1972

Suzuki, Yuya & Ballarin, Francesco 2020

Nesticus latiscapus kosodensis

Yaginuma 1972