Ctenus robustus 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 : 19-25

Ctenus robustus Thorell 1897

Figs 39 , 65–84

Ctenus robustus Thorell 1897: 12 (Description of male and female; 1 male, 1 female, 3 immature syntypes, MCSN, examined; 1 syntype, ZMH, not examined).

Type material. 1 male, 1 female syntypes ( MCSN), Burma, Pegu division, Palon [17°26'N, 95°54'E], Fea leg. 3 immature syntypes ( MCSN), with same data as for preceding specimens .

Note. In Burma several localities named “Palon” exist. According to Hoepli (1896: tavola I) Fea collected at Palon in the Pegu division.

Additional material examined. 1 female ( SMF), Laos, Luang Nam Tha Province, Luang Nam Tha, Ban Tavan (3), N 20°58'57.6'', E 101°29'38.0'', 586 m altitude, small valley with stream, in leaf litter of shrubs and trees, at night, by hand, P. Jäger & S. Bayer leg. 18.XI.2009 .

Diagnosis. Medium to large-sized Ctenidae (total length male 15.4, females 15.3–20.6). Very similar to C. theodorianum spec. nov. in having a modified leg III in males with a ventral hump on the proximal femur covered by small stout spines ( Fig. 84 ) and two ventral cone-shaped humps each with one spine on proximal metatarsus ( Figs 80–83 ) and the female copulatory organs have a similar shape ( Figs 69–76 ); however, males can be distinguished from those of the new species by (1) tegular apophysis undivided in ventral view ( Fig. 66 ; divided in two parts in C. theodorianum spec. nov., cf. Fig. 93 ) with distinct cone-shaped excavation dorsally (best seen in prolateral view, Fig. 65 ; with excavation more indistinct/shallow in C. theodorianum spec. nov., cf. Fig. 92 ); (2) embolus tip shorter, i.e. proximal broad part reaching almost tip and membranous embolic process not extending beyond embolus lateral margin in ventral view ( Fig. 66 ; Embolus narrower, its narrow tip longer, membranous embolic process reaching embolic margin in C. theodorianum spec. nov., cf. Fig. 93 ); (3) RTA with additional hump basally and additional subdistal ridge ( Figs 66–67 ; without such hump or ridge in C. theodorianum spec. nov., cf. Fig. 93 ), (4) tibia III subproximally with strong cone-shaped ventral hump bearing a spine ( Figs 80–83 ; with only slight swelling in C. theodorianum spec. nov., Fig. 115 ), (5) ventral hump of Femur III elongated and not strongly swollen ( Fig. 84 ; circular and more distinctly swollen in C. theodorianum spec. nov., cf. Fig. 111 ). Females show typical characters of other Asian Ctenus spp. : broad median epigynal plate with two lateral teeth ( Figs 69, 73 ), internal duct system consisting of roundish spermathecae short copulatory ducts and complex folds starting from anterior plate ( Figs 71–75 ). No clear diagnostic characters against other Ctenus species can be recognised. Females are distinguished from those of C. theodorianum spec. nov. by slight differences: (1) Longitudinal keel in anterior epigyne more distinct, its lateral margins bending distinctly laterally at a right angle ( Figs 69, 73 ; keel slightly less pronounced in C. theodorianum spec. nov., cf. Figs 96, 101 ); (2) lateral patches fused to anterior epigynal field giving a T-like appearance ( Figs 69, 73 ; lateral patches separated in C.

theodorianum spec. nov., cf. Figs 96, 101 ); (3) first (anterior) windings of internal duct system closer to each other than in C. theodorianum spec. nov. ( Figs 71, 75 ); (4) spermathecae slightly oval ( Figs 71, 75 ; spermathecae spherical in C. theodorianum spec. nov., cf. Figs 98, 103 ).

Moreover, both sexes of C. robustus are larger and exhibit a more reddish brown colour with a distinct white median band on the dorsal prosoma ( Figs 77, 85 , 87, 91 ; more yellowish colour with femora darker and median band indistinct in C. theodorianum spec. nov., cf. Figs 105–110 ). Posterior lateral white dots on ventral opisthosoma are of the same size as others ( Figs 78, 86 , 88 ; dots larger in C. theodorianum spec. nov., cf. Figs 106, 109 ).

Redescription. Male (syntype). PL 8.2, PW 6.4, AW 3.2, OL 7.2, OW 4.8. Spination of palp and legs: palp 141, 100, 1010; femora I p121, d111, r112, II–III p112, d111, r 112, IV p112, d111, r001; patellae 101; tibiae I–II p010, d111, r110, v22222, III–IV p11, d111, r11, v222; metatarsi I–II p111, r111, v223, III p112, d010, r112, v222, IV p112, d010, r112, v2122. Chelicerae with 3 promarginal, 4 retromarginal teeth, elongated patch of ca. 34 tiny denticles along entire cheliceral furrow. Retromargin of chelicerae close to fang base with 7–8 bristles. prominent than in C. theodorianum spec. nov. Embolus arising at 7.30-o’clock-position, short, its tip situated almost centrally. Conductor arising at 12-o’clock-position subdistally. Tegular apophysis arising at 6-o’clockposition from tegulum.

Colour ( Figs 77–79, 85–89 ). Yellowish- to reddish-brown. Dorsal prosoma with white median band, fovea opisthosoma with two posteriorly converging lines of spots and two pairs of distinct spots in the median field close to epigastric furrow. Spinnerets light with anterior lateral spinnerets laterally dark.

Female (female from Laos with syntype in brackets if measured and different). PL 8.0 (8.8), PW 6.1 (6.6), AW 4.0 (4.1), OL 7.3 (11.8), OW 5.3 (8.5). Eye diameters and interdistances: AME 0.39, ALE 0.22, PME 0.51, PLE 0.44, AME–AME 0.22, AME–ALE 0.42, PME–PME 0.26, PME–PLE 0.50, AME–PME 0.11, ALE–PLE 0.20, clypeus AME 0.20, clypeus ALE 0.76. Palp and leg measurements: palp 8.3 (3.0, 1.5, 1.8, -, 2.0), I 20.4 (5.7, 3.1, 5.6, 4.4, 1.6), II 19.2 (5.4, 3.0, 5.1, 4.1, 1.6), III 16.9 (4.9, 2.6, 3.7, 4.2, 1.5), IV 24.0 (6.3, 2.6, 5.7, 7.3, 2.1). Leg formula 4123. Spination of palp and legs: palp 131, 100, 1211, 1013; femora I p021, d111, r111, II p112, d111, r 111, III p112 (1[2]12), d111, r 112, IV p112, d111, r001(2) (001); 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, v2122. Chelicerae with 3 promarginal, 4 retromarginal teeth, elongated patch of 15 proximal and 5 distal denticles along cheliceral furrow. Retromargin of

Copulatory organ as in diagnosis ( Figs 69–76 ). Epigyne about as long as wide. Epigynal field with two slit sense organs close to median plate, which narrows anteriorly, widening medially and narrowing posteriorly again, lateral teeth situated at widest part. Posterior epigyne with distinct lateral furrows. Internal duct system with two large lateral folds running diagonally from medially to laterally, with distinct bend in the middle part. Spermathecae separated by about their diameter from each other, with a second round chamber between spermathecae and fertilisation ducts, the latter pointing medially.

Colour. Yellowish to reddish brown. Dorsal prosoma with distinct white median band, fovea marked black, lateral bands dark reddish-brown. Sternum and ventral coxae dark yellowish brown without pattern, gnathocoxae and labium deep reddish-brown with distal part lighter, gnathocoxae with distinct light lip. Chelicerae deep reddish-brown, shiny iridescent. Palp and legs yellowish- to reddish-brown without distinct pattern. Dorsal opisthosoma with light patch above heart region, in posterior half with indistinct serrated median band. Ventral opisthosoma dark-brown to black with four posteriorly converging rows of small white patches and one to two pairs of light spots in the median field close to epigastric furrow. Spinnerets as in male. For colour of live specimen see Fig. 91 .

Distribution. Known from the type locality ( Burma: Palon) and from Northern Laos (Luang Nam Tha) ( Fig. 39 : 4, 7).

Figures

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

FIGURES 65–68. Ctenus robustus Thorell 1897, syntype male from Burma (Palon), left male palp (65 prolateral, 66 ventral, 67 retrolateral, 68 tip of embolus, ventral). ME—membranous extension of embolus.

FIGURES 69–76. Ctenus robustus Thorell 1897 (69–72 syntype female from Burma, Palon; 73–76 female from Laos, Ban Tavan). 69, 73 Epigyne, ventral; 70, 74 Epigyne, posterior; 71, 75 Vulva, dorsal; 72, 76 Schematic course of duct system, dorsal. K—anterior median keel of epigynal plate.

FIGURES 77–86. Ctenus robustus Thorell 1897, syntype male (77–84) and female (85–86) from Burma (Palon). 77, 85 Habitus dorsal. 78, 86 Habitus, ventral. 79 Habitus, lateral. 80–83 Humps on tibia and metatarsus III, different views. 84 Hump on femur III, ventral.

FIGURES 92–95. Ctenus theodorianum spec. nov., holotype male from Laos (Phou Hiphi, Oudomxai). 92–94 Left male palp (92 prolateral, 93 ventral, 94 retrolateral). 95 Right leg claw I, prolateral.

FIGURES 105–115. Ctenus theodorianum spec. nov. from Laos (Phou Hiphi, Oudomxai) (105–107, 111–115 holotype male, 108–110 paratype female). 105–110 Habitus (105, 108 dorsal; 106, 109 ventral; 107, 110 lateral). 111 Hump on femur III, ventral. 112–115 Humps on tibia and metatarsus III, different views.

FIGURES 96–104. Ctenus theodorianum spec. nov., paratype females from Laos (Phou Hiphi, Oudomxai). 96, 101 Epigyne, ventral; 97, 102 Epigyne, posterior; 98, 103 Vulva, dorsal; 99, 104 Schematic course of duct system, dorsal. 100 Right leg claw I, retrolateral.

FIGURES 87–91. Ctenus robustus Thorell 1897, female from Laos, Ban Tavan, habitus (87, 91 dorsal, 88 ventral, 89 lateral, 90 frontal; 91 living female, not captured).