Ryuthela nishihirai, (HAUPT, 1979)

Xu, Xin, Liu, Fengxiang, Ono, Hirotsugu, Chen, Jian, Kuntner, Matjaž & Li, Daiqin, 2017, Targeted sampling in Ryukyus facilitates species delimitation of the primitively segmented spider genus Ryuthela (Araneae: Mesothelae: Liphistiidae), Zoological Journal of the Linnean Society 181, pp. 867-909 : 884-886

RYUTHELA NISHIHIRAI ( HAUPT, 1979)

Heptathela nishihirai Haupt, 1979, p. 356 , figs 6a–d, 7a–b, 8a–b, 9a–c, 10, 12a–c (description of male and female); Yaginuma, 1979, p. 1, fig. 2; Yaginuma, 1980, p. 44, fig. 2; Yaginuma, 1986, p. 2, figs 1 and 2; Chikuni, 1989, p. 18, fig.2; Yoo & Kim, 2002, p. 28, fig. 47. Ryuthela nishihirai Haupt, 1983, p. 286 , fig. 9g –h, 10a–b, 11b, 12b, 12e, 13g (transferred from Heptathela ); Haupt, 1984, p. 164, figs 3 and 5; Kraus, 1984, p. 375, fig. 2; Haupt, 2003, p. 71, figs 43H, 48A–B, 52A–B, 53.1-24, 55.7–9, 62A; Ono, 2009, p. 80, figs 26–32; Tanikawa, 2013a, p. 33, figs 2A–C, 3A–C, 4A–C.

Type material: Syntypes deposited at NSMT, one female, one male (NSMT-Ar 422–423) from Shuri, Okinawajima island , Okinawa Prefecture, 15 March 1976 (male became adult in October 1977), by M. Nishihira and J. Haupt; examined .

Other material examined: Eight females [XUX-2012- (301–304, 306/307/309A/309B)], Sheyoshi Park , Shuri , Naha, Okinawajima island, Japan, 26.23°N, 127.72°E, 35 m a.s.l., 17 December 2012 ; 5 females [XUX-2012- (541/541A, 542–544)], Asato , Yaese-cho, Okinawajima island, Japan, 26.12°N, 127.74°E, 28 m a.s.l., 17 December 2012 , by D. Li, F. X. Liu and X. Xu; 9 females and 1 juvenile [XUX-2014-(013-022)], Sheyoshi Park , Shuri , Naha, Okinawajima island, Japan, 26.23°N, 127.72°E, 52 m a.s.l., 4 May 2014 ; 3 females (XUX-2014–041/043/044) from Chibana , Gusuku, Okinawajima island, Japan, 26.36°N, 127.81°E, 67 m a.s.l., 7 May 2014 , by D. Li and B. Wu.

Diagnosis: Male R. nishihirai s.s. can be distinguished from all other Ryuthela species by the contrategulum with sparse denticles on proximal margin ( Fig. 5W). Females of R. nishihirai s.s. differ from most other island Ryuthela species by the short receptacular clusters that are close to each other, and further differ from the other species on Okinawajima island by detailed arrangement of the receptacular clusters. These are either fused into one group with obvious granula or form flat receptacular clusters separated from each other ( Fig. 5L, P). However, R. nishihirai s.s. can also be diagnosed from all other Okinawajima island Ryuthela species by the following unique nucleotide substitutions in the standard DNA barcode alignment: A (16), C (173), T (278), G (304), C (475), C (494), G (496), T (571).

Description: Male (lectotype). Body colour somewhat faded. Carapace light yellowish brown with darker frontal margin and black ocular area; opisthosoma yellow, with beige tergites; sternum narrow, much longer than wide; a few long pointed hairs running over ocular mound in a longitudinal row; chelicerae robust with promargin of cheliceral groove with ten denticles of variable size; legs with strong hairs and spines; opisthosoma with 12 tergites, the first tergite forming the superior lorum of the pedicel, the 12th tergite forming the dorsal wall of the anal tubercle, the third widest; seven spinnerets. Measurements: BL 9.05, CL 5.25, CW 4.20, OL 4.20, OW 3.15; ALE> PLE> PME> AME (left PME absent); leg I 17.10 (4.75 + 2.25 + 3.40 + 4.50 + 2.20), leg II 17.15 (4.50 + 2.25 + 3.20 + 4.95 + 2.25), leg III 18.80 (4.25 + 2.10 + 3.45 + 6.00 + 3.00), leg IV 23.90 (5.25 + 2.40 + 4.65 + 7.70 + 3.90).

Palp. Prolateral side of paracymbium unpigmented and unsclerotized; numerous setae and spines at the tip of paracymbium ( Fig. 5X). Prolateral contrategulum with a short and curved spine and sparse denticles on proximal margin ( Fig. 5W); the distal part of contrategulum blunt ( Fig. 5Y, Z); tegulum with a large smooth marginal apophysis ( Fig. 5Y, Z); embolus with a narrow basal part ( Fig. 5X, Z) (cf. Ono, 2009, p. 79, figs 26–29).

Female. Carapace and opisthosoma brown; tergites slightly dark brown; a few long pointed hairs running over ocular mound in a longitudinal row; chelicerae robust with promargin of cheliceral groove with 13–15 strong denticles of variable size; legs with strong hairs and spines; opisthosoma with 12 tergites; 7 spinnerets. Measurements: BL 9.75–13.92, CL 4.85–6.30, CW 3.80–5.80, OL 5.82–7.28, OW 4.10–5.92; ALE> PLE> PME> AME; palp 10.11 (3.28 + 1.90 + 2.25 + 2.68), leg I 12.15 (3.72 + 2.12 + 2.25 + 2.58 + 1.48), leg II 11.76 (3.55 + 2.13 + 2.03 + 2.55 + 1.50), leg III 12.59 (3.53 + 2.18 + 2.05 + 3.05 + 1.78), leg IV 18.82 (5.21 + 2.43 + 3.25 + 5.18 + 2.75).

Female genitalia. A pair of receptacular clusters along the anterior margin of bursa copulatrix; in the dorsal view, their basal parts close to each other ( Fig. 5A–D, K–L, Q–S) or fused to form one large receptacular cluster with obvious granula ( Fig. 5I–J); with a high intraspecific variation in the shape and number of the receptacular clusters.

Distribution: Okinawajima island (Asato, Chibana and Shuri), Okinawa Prefecture, Japan.

Remarks: Tanikawa (2013a) considered all species on Okinawajima island as R. nishihirai s.l., but based on our exhaustive collection on Okinawajima island, results from an integrative analysis of the geographic distribution, phylogenetic and population genetic data, and distinct barcoding gaps in the genus Ryuthela (5.6–6.7% for K2P and 5.3–6.3% for p -distance), we propose seven Ryuthela species on Okinawajima island, including R. nishihirai s.s. Since the holotype locality of R. nishihirai s.l. is Shuri, Okinawajima island ( Haupt, 1979), we treated the specimens collected from the southern part of Okinawajima island (from Chibana to the south Okinawajima island) as R. nishihirai s.s. We examined the syntype series of R. nishihirai deposited at NSMT. According to the remarks in Dunlop, Steffensen & Ono (2014, p. 39), we designated the male specimen deposited at NSMT from syntype series as the lectotype because it is important for describing and classifying all other new species on Okinawajima island. Female genitalia of R. nishihirai s.s. are highly variable. The fused receptacular clusters may be caused by a physical moment at forming their female genital instead of variation; however, we considered them as variation in this study.