Ryuthela sasakii, ONO, 1997

RYUTHELA SASAKII ONO, 1997 View in CoL

Ryuthela sasakii Ono, 1997, p. 151 View in CoL , figs 1–8 (description of male and female); Ono, 2009, p. 80, figs 9–14; Tanikawa, 2013a, p. 38, figs 2G–I, 3G–I, 4G–I, 6F–Y. Ryuthela secundaria Ono, 1997, p. 153 View in CoL , figs 9–10; Ono, 2009, p. 80, figs 15–18 (description of female).

Type material: Female holotype and male allotype deposited at NSMT (NSMT-Ar 3464–3465), collected from the middle area of Shirasegawa River , Gushikawa-son , Kumejima island , Okinawa Prefecture, Japan, 2–3 December 1994 (male became adult on 26 October 1995 at laboratory), by H. Ono; female (NSMT-Ar 3471), Mt. Uegusuku dake, 28 m a.s.l., Kumejima island, Okinawa Prefecture, Japan, 10 March 1997, by H. Ono; examined .

Other material examined: Seven females and three juveniles [XUX-2012-(334-335A, 337–343)] and one male (XUX-2012-340A matured 5 November 2013 at CBEE, College of Life Sciences, Hubei University), collected at Yamazato, Kumejima island , Okinawa Prefecture, Japan, 26.36°N, 126.75°E, 50 m a.s.l. GoogleMaps ; nine females [XUX-2012-(344–348, 350–353)], collected at Yamagusuku , Kumejima island, Okinawa Prefecture, Japan, 26.33°N, 126.78°E, 30 m a.s.l. GoogleMaps ; ten females [XUX-2012-(354–363)], collected at Tokujimu Nature Park , Kumejima island, Okinawa Prefecture, Japan, 26.30°N, 126.80°E, 75 m a.s.l., 19 December 2012 GoogleMaps ; eight females and one juvenile [XUX-2012-(364–366, 368–373)], collected at Maja , Nakazato-son, Kumejima island, Okinawa Prefecture, Japan, 26.36°N, 126.80°E, 40 m a.s.l. GoogleMaps ; ten females [XUX-2012-(374–383)], collected at Uegusuku Castle Site , Mt. Uegusukuson, Kumejima island, Okinawa Prefecture, Japan, 26.38°N, 126.77°E, 300 m a.s.l. GoogleMaps ; five females and three juveniles [XUX-2012-(384–393)], collected at Near Daruma Yama Park , Mt. Daruma, Kumejima island, Okinawa Prefecture, Japan, 26.36°N, 126.76°E, 140 m a.s.l., 20 December 2012 GoogleMaps ; eight females and two juveniles [XUX-2012-(394–403)], collected at Shirasegawa River , Gushikawa-son, Kumejima island, Okinawa Prefecture, Japan, 26.35°N, 126.77°E, 50 m a.s.l., 21 December 2012 GoogleMaps , by D. Li, F. X. Liu and X. Xu; five females [XUX-2014-(108/109A/110A/110B/110C)] and one male (XUX-2014-110, matured 28 September 2014 at CBEE, College of Life Sciences, Hubei University), collected at Maja, Nakazato-son, Kumejima island , Okinawa Prefecture, Japan, 26.36°N, 126.80°E, 60 m a.s.l., 12 May 2014 GoogleMaps ; one female (XUX-2014- 111B) and six males (XUX-2014-111C/D/E/G/K/L, matured September–October 2014 at CBEE, College of Life Sciences, Hubei University) collected at Uezu, Kumejima island , Okinawa Prefecture, Japan, 26.36°N, 126.75°E, 80 m a.s.l., 13 May 2014 GoogleMaps , by D. Li and B. Wu.

Diagnosis: Males of R. sasakii differ from other Ryuthela species by the bifurcated tip of the embolus ( Fig. 14C, D, F) and longer contrategulum ( Fig. 14E); they can be distinguished from R. motobu sp. nov. by the longer contrategular spine ( Fig. 14C, F); from R. iheyana by the curved contrategular spine ( Fig. 14C, F); and from species on Ishigakijima island by the shape of the contrategulum ( Fig. 14C, E, F). Females of R. sasakii can be distinguished from R. owadai by the longer and slender receptacular clusters ( Fig. 14G–R). Ryuthela sasakii can also be diagnosed from R. owadai by the following unique nucleotide substitutions in the standard DNA barcode alignment: A (4), G (10), A (19), T (43), T (163), T (211), A (238), T (239), A (241), A (250), C (271), A (292), T (319), A (322), C (352), A (355), C (361), C (364), C (367), T (370), T (383), C (415), T (433), G (470), T (475), C (502), T (524), A (541), A (601), T (610), T (622).

Description: Male. Carapace and opisthosoma light brown; tergites darker brown; sternum narrow, nearly twice as long as wide; a few long pointed hairs running over ocular mound in a longitudinal row; chelicerae robust with promargin of cheliceral groove containing 10–14 vestigial denticles of variable size; legs with strong hairs and spines; opisthosoma with 12 tergites; 7 spinnerets. Measurements: BL 9.80–13.60, CL 4.35– 6.30, CW 4.10–5.80, OL 4.70–6.90, OW 3.00–4.70; ALE> PLE> PME> AME; leg I 15.68 (4.15 + 1.90 + 3.21 + 4.22 + 2.20), leg II 16.05 (4.10 + 1.90 + 3.05 + 4.50 + 2.50), leg III 15.80 (3.90 + 1.95 + 3.00 + 4.00 + 2.95), leg IV 21.66 (5.30 + 2.00 + 3.95 + 6.65 + 3.76).

Palp. Prolateral side of paracymbium unpigmented and unsclerotized, numerous setae and spines at the tip of paracymbium ( Fig. 14A); long contrategulum with a long, curved spine and several denticles on proximal margin ( Fig. 14C, E, F); embolus with a wide basal part and bifurcated tip ( Fig. 14B, E); in retrolateral view, the marginal apophysis and terminal apophysis of tegulum more or less parallel ( Fig. 14C, F).

Female. Coloration similar to that of male; chelicerae robust with promargin of cheliceral groove containing 12–15 strong denticles of variable size; legs and opisthosoma as in the male; 7–8 spinnerets. Measurements: BL 7.68–14.95, CL 3.63–6.63, CW 3.10–5.90, OL 3.70– 8.05, OW 2.60–6.28; ALE> PLE> PME> AME; palp 7.69 (2.50 + 1.45 + 1.73 + 2.28), leg I 9.60 (3.10 + 1.60 + 1.78 + 2.00 + 1.12), leg II 9.40 (2.91 + 1.60 + 1.57 + 2.07 + 1.25), leg III 9.85 (2.70 + 1.70 + 1.55 + 2.35 + 1.55), leg IV 14.83 (4.00 + 1.97 + 2.55 + 4.01 + 2.30).

Female genitalia. A pair of receptacular clusters with the basal parts separated or fused and with the heartshaped distal part ( Fig. 14K, O); the opening part of receptacular clusters is located at the ventral part of bursa copulatrix, but visible in the dorsal view; the dorsal view of each receptacular cluster is slender ( Fig. 14I, L–N).

D i s t r i b u t i o n: K u m e j i m a i s l a n d (Ya m a z a t o, Yamagusuku, Tokujimu Nature Park, Maja, Uegusuku Castle Site, Mt. Daruma, Shirasegawa River, Uezu), Okinawa Prefecture, Japan.