Ctenus simplex Thorell 1897

Jäger, Peter, 2012, Asian species of the genera Anahita Karsch 1879, Ctenus Walckenaer 1805 and Amauropelma Raven, Stumkat & Gray 2001 (Arachnida: Araneae: Ctenidae), Zootaxa 3429 (1), pp. 1-63 : 29-33

Ctenus simplex Thorell 1897

Figs 39 , 116–137

Ctenus simplex Thorell 1897: 16 (description of male; holotype examined)

Ctenus trabifer — Gravely 1931: 234, fig. 3A (description of female from Tenasserim, NHM; not examined) Additional material examined. 1 male, 2 females ( SMF), Laos, Luang Prabang Province, Nam Ou, Nong Khiao, Tham Pathok, N 20°33'682'', E 102°37'929'', 373 m altitude, outside cave, leaf litter, sieving, by day, P. Jäger & F. Steinmetz leg. 17.–18.III.2007. 1 female ( SMF), with same data as for preceding specimens, but: leaf litter, banana trees, bushes, by hand, by night, P. Jäger leg. 29.II.2008. 1 female ( SMF), with same data as for preceding specimen, but: Winkler apparatus. 1 female ( SMF), Laos, Luang Prabang Province, Luang Prabang town, Phou Si, N 19°53'390'', E 102°08'061'', 299 m altitude, disturbed secondary forest, by hand, by night, P. Jäger & J. Altmann leg. 4.+ 9.III.2006. 1 female ( SMF), Laos, Vientiane Province, Vang Vieng , Tham Padeng , N 18°55.486', E 102°26.143', 282 m altitude, in front of cave, at night, by hand, P. Jäger & V. Vedel leg. 19.XI.2004. Diagnosis. Medium-sized Ctenidae (total length male 11.7, female 11.9–18.3). Distinguished from other Ctenus spp. , but not C. holthoffi spec. nov., by the modified coxa IV in males with pointed ventral hump ( Figs 129–130 ). Distinguished from C. holthoffi spec. nov. by the much longer embolus, the smaller tegular apophysis and the RTA distally straight (Figs 117, 120). Females are distinguished from other Asian representatives by the prominent anterio-lateral “shoulders” of the median epigynal plate ( Figs 122–123 ). See also note below .

Redescription. Male (male from Nong Khiao with data of holotype in square brackets, in spination only differences listed). PL 6.0 [6.2], PW 4.6 [4.7], AW 2.5 [2.5], OL 5.7, OW 3.5. Eye diameters and interdistances: AME 0.29, ALE 0.21, PME 0.39, PLE 0.34, AME–AME 0.16, AME–ALE 0.33, PME–PME 0.18, PME–PLE 0.32, AME–PME 0.06, ALE–PLE 0.14, clypeus AME 0.12, clypeus ALE 0.47. Palp and leg measurements: palp 7.7 (3.0, 1.3, 1.4, -, 2.0), I 17.65 (4.5, 2.3, 4.9, 4.4, 1.55), II 16.6 (4.4, 2.3, 4.5, 4.0, 1.4), III 14.4 (4.0, 2.3, 4.5, 4.0, 1.4), IV 21.7 (3.3, 2.2, 5.3, 7.1, 1.8). Leg formula 4123. Spination of palp and legs: palp 141, 100, 1010; femora I p021, d111, r112, II–III p112, d111, r 112, IV p112, d111, r002; patellae 101; tibiae I–II p010, r110 [tibia I 010], v22222, III–IV p11, d111 [11], r11, v222; metatarsi I–II p111, r111, v222 [223], III p112, d010, r112, v222, IV p112, d010, r112, v21112 [12122]. Chelicerae with 3 [3] promarginal, 5 [5] retromarginal teeth, and with patch of several tiny denticles close to promarginal teeth. Retromargin of chelicerae close to fang base with 5–7 [8] bristles. Sparse scopula restricted almost entirely to tarsi, only metatarsi I–II with sparse scopula hairs. Leg claw I with 5 secondary teeth, leg claw IV with 6 teeth (3 large and 3 small). Position of tarsal organ: I 0.85, II 0.83, III 0.77, IV 0.77.

Palp as in diagnosis (Figs 116–121). Retrolateral cymbial margin with extension. RTA with broad base and slightly triangular appearance; slightly bent in retrolateral view. Cymbium tip slightly conical, retro-proximally with small extension. Embolus arising at 7.30-o’clock-position, long, its tip situated at distal tegulum. Conductor arising at 12-o’clock-position distally. Tegular apophysis arising subcentrally from tegulum, elongated.

Colour ( Figs 127–129 ). Reddish brown to dark yellowish brown. Dorsal prosoma with light median band with characteristic widening behind eyes and some white hairs left; with distinctly marked fovea and radial markings. Sternum, ventral coxae, labium and gnathocoxae dark yellowish-brown, posteriorly partly with diffused black irregular pattern consisting of spots and lines. Ventral opisthosoma dark with rows of light muscle sigilla; epiandrium and anterior bands light. Anterior lateral spinnerets baso-medially light, otherwise dark, posterior lateral and median spinnerets and anal tubercle light.

Description. Female (large female together with male from Nong Khiao). PL 7.4, PW 5.8, AW 3.5, OL 10.9, OW 7.8. Eye diameters and interdistances: AME 0.33, ALE 0.26, PME 0.46, PLE 0.40, AME–AME 0.18, AME– ALE 0.40, PME–PME 0.22, PME–PLE 0.52, AME–PME 0.11, ALE–PLE 0.22, clypeus AME 0.16, clypeus ALE 0.63. Palp and leg measurements: palp 7.6 (2.7, 1.4, 1.6, -, 1.9), I 17.5 (5.1, 2.8, 4.3, 3.8, 1.5), II 17.0 (4.9, 2.8, 4.2, 3.7, 1.4), III 15.0 (4.3, 2.2, 3.4, 3.6, 1.5), IV 21.5 (5.6, 2.5, 4.8, 6.6, 2.0). Leg formula 4123. Spination of palp and legs: palp 141, 100, 1211, 1013; femora I p021, d111, r012, II p112, d111, r 111, III p012, d111, r012, IV p112, d111, r002; patellae I–II 000, III–IV 101; tibiae I–II v22222, III–IV p11, d111, r11, v222; metatarsi I–II v222, III p112, d010, r112, v222, IV p112, d010, r112, v21122. Chelicerae with 3 promarginal, 5 retromarginal teeth, and with patch of several tiny denticles close to promarginal teeth. Retromargin of chelicerae close to fang base with 8– 9 bristles. Claw tufts and scopulae as in male. Leg claw I with 3 secondary teeth, leg claw IV with 5 (3 large + 2 small). Position of tarsal organ: I 0.81, II 0.79, III 0.75, IV 0.74.

Copulatory organ as in diagnosis ( Figs 122–126 ). Epigynal field anterio-laterally with two separate roundish patches, and laterally with two pairs of slit sense organs. Median plate wide anteriorly, narrowing slightly posteriorly, lateral teeth situated posteriorly at narrowest part. Internal duct system with two indistinct lateral folds running diagonally from medially to laterally. Spermathecae slightly ovoid and separated by about one of their diameter from each other, with a small round chamber between spermathecae and fertilisation ducts, the latter curved distally. Internal duct system close to spermathecae with glandular pores.

Colour ( Figs 131–136 ). As in male, but generally darker. Gnathocoxae and labium dark reddish-brown, gnathocoxae with light distal lip. Femur IV especially laterally and ventrally with annulate pattern. Opisthosoma with contrast between light and dark parts less distinct. For colour of a living specimen see Fig. 137 .

Variation. Females [n=5]: PL 6.3–6.6, OL 5.9–8.6. There were two distinctly different shapes of the “median plate shoulders” in females ( Fig. 123 ). The serrated median band on the dorsal prosoma may be indistinct in preserved specimens ( Fig. 131 ). The denticles in the cheliceral furrow may be distributed along entire furrow. The vulva of the female from Vang Vieng showed only slight variation in comparison to females from Nong Khiao.

Distribution. Known from the type locality, Burma, Tenasserim ( Thorell 1897), and three different localities in Northern Laos: Luang Prabang Province (Nong Khiao, Luang Prabang), Vientiane Province (Vang Vieng) ( Fig. 39 : 5, 9–11).

Note. Similar epigynal septal “shoulders” are present in females of “ Ctenus tamerlani Roewer 1951 ”, known also from Burma, but the epigyne of the latter species is slightly wider and exhibits additional longitudinal ridges within lateral parts of the median plate. See also note below.

Figures

FIGURE 39. Records of Ctenus spp. in South and Southeast Asia. 1 Between Chitre and Chandrung, Nepal. 2–5 Burma (2

FIGURES 127–137. Ctenus simplex Thorell 1897 from Laos (127–130 male from Nong Khiao, Luang Prabang; 131–136 females from Nong Khiao, Luang Prabang; 137 living female from Vang Vieng, Vientiane). 127–129, 131–137 Habitus (127, 131, 134, 137 dorsal; 128, 132, 135 ventral; 129, 133 lateral; 136 frontal). 130 Hump on coxa IV, posterio-ventral.

FIGURES 122–126. Ctenus simplex Thorell 1897, females from Nong Khiao, Luang Prabang, Laos. 122–123 Epigyne, ventral; 124 Epigyne, posterior; 125 Vulva, dorsal; 126 Schematic course of duct system, dorsal. S—shoulder of epigynal plate.