Tetrablemma medioculatum O. Pickard-Cambridge, 1873 from Sri Lanka (see Lehtinen 1981).

The gender of Tetrablemma is neuter, therefore two species names described previously are amended (see below). The ending “-ensis” denotes a place, a locality or a country. It forms an adjective with two endings: “-ensis” for genera masculine or feminine in gender, and “-ense” for genera neuter in gender.

Twenty-seven species were known before the current study: T. alaus Burger, Harvey & Stevens, 2010, T. alterum Roewer, 1963, T. benoiti (Brignoli, 1978), T. brevidens Tong & Li, 2008, T. brignolii Lehtinen, 1981, T. deccanense (Tikader, 1976), T. extorre Shear, 1978, T. helenense Benoit, 1977, T. loebli Bourne, 1980, T. magister Burger, 2008, T. manggarai Lehtinen, 1981, T. marawula Lehtinen, 1981, T. mardionoi Lehtinen, 1981, T. medioculatum O. Pickard-Cambridge, 1873, T. medioculatum cochinense Lehtinen, 1981, T. medioculatum gangeticum Lehtinen, 1981, T. menglaense Lin & Li, 2014 (species epithet corrected, original published as T. menglaensis), T. namkhan Lin, Li & Jäger, 2012, T. nandan Lin & Li, 2010, T. okei Butler, 1932, T. phulchoki Lehtinen, 1981, T. rhinoceros (Brignoli, 1974), T. samoense Marples, 1964, T. thamin Labarque & Grismado, 2009, T. viduum (Brignoli, 1974), T. vietnamense Lehtinen, 1981, T. ziyaoense Lin & Li, 2014 (species epithet corrected, original published as T. ziyaoensis).

Angola, Australia, Cambodia, China, St. Helena, India, Laos, Indonesia, Micronesia, Myanmar, Nepal, Queensland, Samoa, Seychelles, Sri Lanka, Trinidad, Victoria and Vietnam. These previously described species live mainly in the forest litter or in caves.

Holotype ♂ (SMF), CAMBODIA: Kep Province, Kep, Phnom Kep, secondary forest, leaf litter, elevation 105 m, 10°28'50"N, 104°17'50"E, 4–8 July 2017, P. Jäger leg., sieving. Paratypes 7♂, 8♀ (5 ♂, 6♀ SMF; 2♂, 2♀ NHMSU), same data as holotype.

The specific name refers to the type locality; adjective.

With the exception of T. marawula Lehtinen, 1981, T. brevidens Tong & Li, 2008, T. thamin Labarque & Grismado, 2009, and T. ziyaoense Lin & Li, 2014, this new species can be distinguished from other congeners by the lack of modified teeth or tubercle on the clypeus or the ocular area in both sexes, the embolus furcated at proximally 1/3 position, the extra-long inner vulval plate nearly 3 × as long as the central process (Figs 1E–H, 2B–C, F–G). It differs from T. marawula by the wider bulb, the sharpened embolic tip and the longer straight inner vulval plate (Figure 2A, B, D, G vs. Lehtinen 1981: figs 266, 283); differs from T. brevidens by the more strongly coiled spermophor, the furcate embolus, the thinner long inner vulval plate, and shorter postgenital scutum (Figure 2A, C, G vs. Tong 2013: figure 97E–H); male differs from T. thamin by the narrower palpal tibia, the larger bulb, and the bifurcate embolic tip (trifurcate in T. thamin), female by the presence of a central process and the longer inner vulval plate (Figure 2A, C, D, G vs. Labarque and Grismado 2009: figs 1–3); and differs from T. ziyaoense by the converging cheliceral horns, the reticulated clypeus in both sexes (smooth in female of T. ziyaoense), the course and outlet position of spermophor, the precurved posterior margin of the pulmonary scutum, the thinner, straight inner vulval plate, the narrower vulval stem, and the lack of a distinct furrow on the preanal scutum (Figs 1A–H, 2A–G vs. Lin and Li 2014: figs 13A–H, 14A–D, 15A–C).

Figure 1. 

Tetrablemma kepense sp. n., male holotype (A, B, E, G) and female paratype (C, D, F, H). A–F habitus G–H prosoma. A, C dorsal B, D ventral E–F lateral G–H anterior. Abbreviations: CH = cheliceral horns. Scale bars: A–F 0.5 mm, G–H 0.2 mm.

Male (holotype). Measurements: total length 1.08; carapace 0.42 long, 0.37 wide, 0.34 high; abdomen 0.70 long, 0.58 wide, 0.35 high; clypeus 0.14 high; sternum 0.28 long, 0.29 wide. Length of legs: I 1.29 (0.43, 0.12, 0.32, 0.20, 0.22); II 1.22 (0.40, 0.11, 0.30, 0.20, 0.21); III 1.08 (0.33, 0.11, 0.25, 0.19, 0.20); IV 1.38 (0.45, 0.12, 0.36, 0.23, 0.22).

Prosoma (Figure 1A, B, E, G): reddish-brown, carapace finely reticulated, marginally rugose; four eyes in one group, in posterior half of carapace, white with black ocular base, ALE>PLE, ALE and PLE adjacent; cephalic part raised; clypeus high, sloping forward, with sparse setae, marginally round; cheliceral horns long, distal tip sharp, and tilted, cheliceral lamina developed; endites basally wide, distally narrow, labium triangular, distally blunt; sternum irregularly reticulated, scutellate, marginally strongly rugose, posterior corner truncated. Legs: yellowish-orange, cuticle striated; tibiae I–III with three trichobothria, four on tibia IV, and one on metatarsi I–IV. Opisthosoma: pale reddish-brown, dorsal scutum oval, surface nearly smooth, slightly granulated, posteriorly truncated; ventral scutum reticulated; lateral scutum I long, and exceeding beyond the posterior margin of preanal scutum; postgenital scutum straight; preanal scutum approximately oblong, slightly curved.

Palp (Figure 2A–D): femoral cuticle granulated, approx. 2.5 x longer than patella; patella normal; tibia large, swollen, approx. 1.5 x wider than femur, with a trichobothrium disto-dorsally; cymbium short, triangular from lateral view, bearing long setae; bulb pear-shaped, surface smooth; embolus tubular, distinctly sclerotized, arising from the apex of bulb; embolic tip sharply pointed, lamellar bifurcation at proximally 1/3 position; spermophor coiled into two loops, abruptly twisting to narrow, and open at the embolic tip.

Female (one paratype). Measurements: total length 1.16; carapace 0.44 long, 0.38 wide, 0.34 high; abdomen 0.72 long, 0.61 wide, 0.37 high; clypeus 0.13 high; sternum 0.28 long, 0.30 wide. Length of legs: I 1.26 (0.42, 0.12, 0.31, 0.20, 0.21); II 1.19 (0.40, 0.11, 0.29, 0.19, 0.20); III 1.09 (0.34, 0.11, 0.26, 0.18, 0.20); IV 1.34 (0.44, 0.12, 0.35, 0.22, 0.21).

Prosoma (Figure 1C, D, F, H): coloration and modification as in male, but ocular area in anterior part of the carapace, chelicerae without long horn, only a small nodule fronto-proximally. Clypeus slightly lower than in male, palps distinctly reduced, palpal tibia with a dorsal trichobothrium. Legs as in male. Opisthosoma: dorsal and ventral scuta as in male, except for darker coloration; lateral scutum I long, extending beyond posterior margin of preanal scutum; postgenital scutum long, bearing a row of long setae, mesally narrow, laterally wide; preanal scutum more smooth, wider than long, nearly rectangular, with sparse stiff setae.

Epigyne and vulva (Figure 2F, G): epigynal fold long and obvious; epigynal pit distinct, gap-shaped, opening at the posterior margin of the pulmonary scutum; vulval stem sclerotized; vulval ducts weakly sclerotized, translucent, widely “V”-shaped, apical end connected to seminal receptacles; seminal receptacles inflated, saccular, transparent; inner vulval plate extra-long, straightly tubular, broad at base; central process short, proximally contracted, distally swollen.

Forest leaf litter.

Known only from the type locality (Figure 6).

Figure 2. 

Tetrablemma kepense sp. n., male holotype (A–D) and female paratype (E–G). A, B, D left palp C embolic tip E genital area (untreated) F–G cleared vulva (lactic acid-treated). A prolateral B, C frontal D retrolateral E, F ventral G dorsal. Abbreviations: CP = central process; Cy = palpal cymbium; E = embolus; EF = epigynal fold; EP = epigynal pit; Et = embolic tip; IVP = inner vulval plate; PA = preanal scutum; Pb = palpal bulb; POG = postgenital scutum; Sd = spermophor; SR = seminal receptacle; Ti = palpal tibia; VD = vulval duct; VS = vulval stem. Scale bars: A, B, D–G 0.2 mm, C 0.05 mm.

Holotype ♂ (SMF), CAMBODIA: Battambang Province, SW Battambang, Phnom Romsay Sok, an anonymous cave, elevation 100 m, 12°57'28"N, 103°6'32"E, 19 July 2017, P. Jäger & S. Münnich leg. Paratypes 7♂, 20♀ (4♂, 10♀; SMF 3♂, 10♀ NHMSU), same data as holotype.

The specific name refers to the type locality; adjective.

This new species can be distinguished from other congeners with the exception of T. loebli Bourne, 1980 and T. nandan Lin & Li, 2010 by the protruding ocular area of carapace and the vestigial four eyespots in both sexes, the exceptionally slender bulb, and the absence of an epigynal fold in the female vulva (Figs 3A–H, 4A–F). T. sokense sp. n. seems similar to T. loebli and T. nandan in the appearance of habitus, the shape and configuration of genital organs, but differs from T. loebli by the reduced eyes without any black pigments in both sexes, the straight cheliceral horn in lateral view, the narrower bulb, the shorter, twisted embolus, the stubby inner vulval plate, and the falcate central process (Figure 3A, C, E–H vs. Bourne 1980: figs 9–10, 14, 16; Lehtinen 1981: figs 219, 221–223); and differs from T. nandan by the converged eyes and flat cephalic area in both sexes, the regular, not swollen palpal femur and tibia, the swollen bulb with a more distorted embolus, the shorter, fingerlike inner vulval plate and the lack of epigynal fold (Figs 3E–H, 4A–F vs. Lin and Li 2010: figs 38–39, 44–49).

Figure 3. 

Tetrablemma sokense sp. n., male holotype (A, B, E, G) and female paratype (C, D, F, H). A–F habitus G–H prosoma. A, C dorsal B, D ventral E–F lateral G–H anterior. Abbreviations: CH = cheliceral horns. Scale bars: A–F 0.5 mm, G, H 0.2 mm.

Male (holotype). Measurements: total length 1.48; carapace 0.53 long, 0.50 wide, 0.48 high; abdomen 1.07 long, 0.60 wide, 0.53 high; clypeus 0.15 high; sternum 0.31 long, 0.29 wide. Length of legs: I 1.42 (0.47, 0.13, 0.35, 0.24, 0.23); II 1.35 (0.44, 0.12, 0.34, 0.23, 0.22); III 1.15 (0.36, 0.11, 0.27, 0.20, 0.21); IV 1.44 (0.49, 0.12, 0.37, 0.23, 0.23).

Prosoma (Figure 3A–B, E, G): reddish-brown, carapace finely reticulated, marginally rugose; four white eyes, as vestigial eyespots in a group, ocular area in anterior half of carapace; ALE>PLE, ALE and PLE adjacent; cephalic part raised, flat top; clypeus high, sloping forward, with sparse setae, marginally round; cheliceral horns long, straight, distal tip sharp, cheliceral lamina developed; endites basally wide, distally narrow, labium trapezoidal, distally truncated; sternum finely reticulated, marginally strongly rugose, posterior end truncated. Legs: yellowish-orange, cuticle striated; tibiae I–III with three trichobothria, two on tibia IV, and one on metatarsi I–IV. Opisthosoma: orange, dorsal scutum long oval, surface reticulated, weakly granulated, bearing sparse long setae; ventral scutum reticulated; lateral scutum I long, and exceeding beyond the posterior margin of preanal scutum; postgenital scutum straight, banded, mesally wide and laterally narrow; preanal scutum flat, nearly oval, with long setae.

Palp (Figure 4A–C): femoral cuticle ventrally granulated, approx. 2.2 × longer than patella; patella short and smooth, distinctly longer than cymbium; tibia wide, swollen, approx. 1.2 x wider than femur, with a distal-dorsally trichobothrium; cymbium short, constricted, bearing sparse long setae; bulb long pear-shaped, surface of dilated area smooth, surface of sub-distal area rugose; embolus strongly sclerotized, starting from the apex of bulb; embolic tip cuneate, twisted, sharply pointed; spermophor coiled into a loop in bulb, abruptly twisting to narrow, and open at the embolic tip.

Figure 4. 

Tetrablemma sokense sp. n., male holotype (A–C) and female paratype (D–F). A–C left palp D genital area (untreated) E, F cleared vulva (lactic acid-treated). A prolateral B frontal C retrolateral D–E ventral F dorsal. Abbreviations: CP = central process; Cy = palpal cymbium; E = embolus; EP = epigynal pit; Et = embolic tip; IVP = inner vulval plate; PA = preanal scutum; Pb = palpal bulb; POG = postgenital scutum; Sd = spermophor; SR = seminal receptacle; Ti = palpal tibia; VD = vulval duct; VS = vulval stem. Scale bars: 0.2 mm.

Female (one paratype). Measurements: total length 1.52; carapace 0.55 long, 0.49 wide, 0.47 high; abdomen 1.03 long, 0.67 wide, 0.60 high; clypeus 0.14 high; sternum 0.32 long, 0.28 wide. Length of legs: I 1.39 (0.46, 0.12, 0.37, 0.23, 0.21); II 1.30 (0.42, 0.12, 0.33, 0.22, 0.21); III 1.18 (0.37, 0.11, 0.28, 0.22, 0.20); IV 1.45 (0.48, 0.12, 0.38, 0.24, 0.23).

Prosoma (Figs 3C–D, F, H, 5): coloration and modification as in male, but instead cheliceral horns a small nodule fronto-proximally. Clypeus lower than in male, palps distinctly reduced, palpal tibia with a dorsal trichobothrium. Legs as in male. Opisthosoma: dorsal and ventral scuta as in male; lateral scutum I long, extending beyond posterior margin of preanal scutum; postgenital scutum long, straight, bearing a row of long setae, mesally wide, laterally narrow; preanal scutum weakly sculptured, wider than long, nearly rectangular, with sparse stiff setae.

Epigyne and vulva (Figure 4E–F): epigynal fold absent; epigynal pit indistinct, oval, opening at the posterior margin of the pulmonary scutum; vulval stem short, columnar, strongly sclerotized; vulval ducts wide, translucent, widely “V”-shape; seminal receptacles saccular, transparent; inner vulval plate fingerlike, distinctly sclerotized, slightly tilting; central process small, weakly sclerotized, shorter than inner vulval plate, apically falcate.

Cave. The cave entrance was ca. 80 altitudinal meters above the ground at an isolated limestone hill. Almost under every stone only one spider was found; silken strands used by the spiders may be the reason for this territoriality (Figure 5). It was the highest density of Tetrablemmidae observed in a cave by the last author. Besides Tetrablemmidae, there were Oonopidae (also found under stones), Pholcidae, Sparassidae, Uloboridae, Hersiliidae, Agelenidae, Amblypygi and Isopoda.

Figure 5. 

Tetrablemma sokense sp. n., live female in cave, Cambodia (green arrows indicating silken strands, photograph by P. Jäger).

Known only from the type locality (Figure 6).

Figure 6. 

Distribution records of Tetrablemma kepense sp. n. (pink balloon) and Tetrablemma sokense sp. n. (red balloon) in Cambodia.