Tetrablemma sokense , Lin, Yucheng, Li, Shuqiang & Jaeger, Peter, 2018

Lin, Yucheng, Li, Shuqiang & Jaeger, Peter, 2018, Tetrablemmidae, a spider family newly recorded from Cambodia (Arachnida, Araneae), ZooKeys 777, pp. 43-55: 44-47

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scientific name

Tetrablemma sokense

sp. n.

Tetrablemma sokense  sp. n. Figs 3, 4, 5, 6

Type material.

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 3 A–H, 4 A–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 3 E–H, 4 A–F vs. Lin and Li 2010: figs 38-39, 44-49).


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 3 A–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 4 A–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.

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 3 C–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 4 E–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.

Habitat and biology.

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  .


Known only from the type locality (Figure 6).