Draconarius tortus Chen, Zhu & Kim 2008

Jiang, Xuan-Kong, Guo, Xuan, Yu, Zhi-Gang & Chen, Hui-Ming, 2017, First description of the male of the eyeless spider Draconarius tortus Chen, Zhu & Kim 2008 from China (Araneae: Agelenidae: Coelotinae), Zootaxa 4294 (1), pp. 141-144 : 141-144

Draconarius tortus Chen, Zhu & Kim 2008 (Figs 1–15)

Draconarius tortus Chen et al. 2008: 86 , figs 2–5.

Material examined. CHINA: Guizhou: 1 male, 2 females, 2 subadult males, Xingyi City, Jingnan Town , Shanjiao Village , Feilong Cave , 24°58′13.7′′N, 104°52′54.7′′E, X.K. Jiang, H.M. Chen & X. Guo leg. 10.1. 2017 ( IBGAS).

Diagnosis. Male similar to that of D. wudangensis (Chen & Zhao 1997) , but distinguished from the latter by the blunt patellar apophysis ( Figs 7 , 13 ), broad median apophysis and slender conductor ( Figs 6 , 12 ). The female is similar to that of D. yosiianus in having no eyes and looped spermathecae, but distinguished from the latter by the broad and truncated epigynal teeth ( Figs 8–9 , 14 ) and spermathecae more convoluted ( Figs 10 , 15 ).

Description. Male. Total length 7.02. Prosoma length 3.51, width 2.49; opisthosoma length 3.37, width 1.99. Eyes completely reduced (Figs 1, 3). Chelicerae with 3 promarginal and 2 retromarginal teeth. Leg measurements: I 14.55 (3.92, 4.77, 3.65, 2.21); II 13.48 (3.63, 4.27, 3.43, 2.15); III 12.86 (3.37, 3.75, 3.73, 2.01); IV 16.52 (4.16, 5.02, 4.97, 2.37). Leg formula: IV, I, II, III. Other characters similar to female.

Patellar apophysis strong, with blunt tip. RTA with distal end slightly extending beyond tibia. Lateral tibial apophysis small. Cymbial furrow longer than half cymbial length. Conductor simple. Conductor dorsal apophysis stout. Conductor lamella developed. Median apophysis broad and spoon-like. Embolus filiform and long, arising retrolateroproximally from tegulum ( Figs 5–7 , 11–13 ).

Female. For detailed description, see Chen et al. (2008). Epigynal teeth short, broad, truncated, widely separated from each other. Atrium wider than long, situated posteriorly. Copulatory duct situated between spermathecae. Spermathecal head short, originated medially. Spermathecal base small. Spermathecal stalk elongated, convoluted in 7 loops, tapered ( Figs 8–10 , 14–15 ).

.

FIGURES 1–4. Draconarius tortus . 1, 3 Male. 2, 4 Female (1–2 dorsal, 3–4 frontal).

Distribution. Only known from type locality, Feilong Cave in Guizhou Province, China.

Notes. Based on the structures of the male palp and female epigyne, this species obviously belongs to the venustus group ( Wang 2003).

This species lives under stones or in crevices on the ground, weaving a sheet-web. There is another Coelotinae found in this cave, Platocoelotes brevis Liu & Li 2008 , but it is troglophilic, inhabiting the entrance of the cave, while D. tortus is found deeper inside the cave (at least 200 meters from the entrance), habitats of both species do not overlap.

Parthenogenesis is a rare phenomenon in spiders, and evidenced only for three species in laboratory ( Korenko et al. 2009). In Coelotinae, four species are thought to be parthenogenetic, C. troglocaecus , D. tortus , D. proximus and D. digituliscaput . They are all troglobitic and eyeless. However, our finding testifies that D. tortus is actually amphigenetic. The males had not been collected in the original investigation in the type locality, possibly due to the insufficient survey.

Usually, adult males and females of Coelotinae occur in large number from late autumn to following spring. And because after mating most males die ( Wang 2002), it could be more difficult to find males than females, when the mass occurrence period was missed. Also, there has been no follow-up survey undertaken after the first investigation for D. proximus and D. digituliscaput . Their males may be found in future surveys. However, C. troglocaecus is probably parthenogenetic by its strongly degenerated structure of genitalia and also indication by no male finding even through multiple surveys carried out so far, but needs further testing.

Figures

FIGURES 5 – 10. Draconarius tortus. 5 – 7 Left male palp (5 prolateral, 6 ventral, 7 retrolateral). 8 – 9 Epigyne (8 ventral, 9 posterior). 10 Vulva, dorsal. Arrows indicating epigynal teeth.

FIGURES 11 – 15. Draconarius tortus. 11 – 13 Left male palp (11 prolateral, 12 ventral, 13 retrolateral). 14 Epigyne, ventral. 15 Vulva, dorsal. Abbreviations: A—atrium, C—conductor, CDA—conductor dorsal apophysis, CF—cymbial furrow, CL—conductor lamella, E—embolus, ET—epigynal teeth, FD—fertilization duct, LTA—lateral tibial apophysis, MA—median apophysis, PA—patellar apophysis, RTA—retrolateral tibial apophysis, S—spermathecae, SH—spermathecal head, TS—tegular sclerite. Scale bars: 11 – 13: 0.5 mm, 14 – 15: 0.2 mm.