Tetrablemma nandan, Lin & Li, 2010

Lin, Yucheng & Li, Shuqiang, 2010, New armored spiders of the family Tetrablemmidae from China, Zootaxa 2440 (1), pp. 18-32 : 28-30

Tetrablemma nandan sp. nov.

Figs 38–49 , 50

Type material: Holotype: male ( IZCAS), Liangfeng Cave (Alt.: 598 m), Encun Village, Nandan County [25°04´N, 107°38´E, Guangxi, China], 4 March 2007, Y.C. Lin and J. Liu leg. Paratypes: 23 males, 52 females, same locality data as holotype, 15 August 2007, Y.C. Lin and Y.H. Guo leg. ( IZCAS) .

Etymology. The specific name is derived from a noun in apposition of the type locality.

Diagnosis. The new species seems closest to Tetrablemma loebli Bourne, 1980 but differs by 1) the presence of a tibial and two metatarsal tuber distally, 2) the longer apophysis at chelicera anteriorly, 3) the pedipalpal tibia swollen, subequal to femur in length, 3) the longer and narrower pedipalpal bulb, 4) the short and horny embolus. In addition, 5) the cephalica pars upheaved, higher than ocular area in male, 6) the triangular epigynal pit and 7) the difference in central process and inner vulval plate, can also easily distinguished from its congeners.

Description. Male: 1.04–1.10. Coloration yellow-reddish. Prosoma length 0.49–0.53, width 0.39–0.42, maximal height 0.36–0.40. Opisthosoma length 0.72–0.77, width 0.55–0.58. Four eyes in a group, AME and PME absent, ALE slightly larger than and nearly adjoined PLE, PLE separated by more than 1.5 times of their diameter. Ocular area black, no modification. Cephalic pars sleek, higher than ocular area, two small tubers at apex. Clypeus profile anteriorly triangular margin. Cheliceral apophysis narrow, long, slightly turnup at end ( Figs 38, 39 ), with a small tuber at base. Thoracic pars and sternum finely retiform, rugose marginally. All sections of legs but patellae transversely striated. One ventral tuber located at tibia I distally. Metatarsus II with two distal tubers ( Fig. 43 ). Leg measurements: I 1.16 (0.40, 0.10, 0.26, 0.18, 0.22); II 1.06 (0.32, 0.10, 0.24, 0.18, 0.22); III 0.92 (0.28, 0.10, 0.18, 0.18, 0.18); IV 1.22 (0.38, 0.10, 0.30, 0.22, 0.22). Leg formula: Leg formula: 4-1-2-3. Of opisthosoma dorsal scutum short ovoid, finely transversely striated. Ventral scutum with incontinuous small grooves. Lateral scutum I short, perigenital plates present.

Pedipalpal femur robust, subequal to tibia and two times to patella in length. Tibia swollen. Metatarsus short. Pedipalpal bulb long, with a small notch proximally. Embolus short and horny, distinctly sclerotized.

Female: 1.10–1.15. Prosoma length 0.52–0.56, width 0.41–0.43, maximal height 0.38–0.40, Opisthosoma length 0.78–0.82, width 0.68–0.71. Clypeus sloping forward. Cephalic pars flat. Four eyes ovoid, ALE smaller slightly than PLE. A small anterior tuber at chelicera proximally ( Fig. 42 ). The modification of dorsal shield of prosoma, sternum and legs same as in male. Leg measurements: I 1.18 (0.38, 0.10, 0.28, 0.20, 0.22); II 1.06 (0.34, 0.10, 0.24, 0.18, 0.20); III 0.98 (0.30, 0.10, 0.20, 0.18, 0.20); IV 1.28 (0.40, 0.10, 0.32, 0.22, 0.24). Leg formula: 4-1-2-3. Lateral scutum I anteriorly short, not beyond the posterior brim of booklung opening. Pulmonary plate, postgenital and preanal plate with many plumose setae. Epigynal area with distinct furrows and one strong fold. Epigynal fold broad mesially and narrow laterally. Perigenital plate existed. Postgenital plate longer than perigenital plate, equal to the width of preanal plate.

Vulval stem wide basally, lateral horns sclerotized distinctly, supporting the base of vulval ducts of seminal receptacula as in all species of Tetrablemma . Central process contracted mesially and bulged distally, shorter than inner vulval plate that curved to ventral opisthosoma. Vulval duct narrow, slightly sclerotized at base. Epigynal pit tiny and protruded, disparted with vulval stem and lateral horns ( Fig. 49 ).

Natural history. The spider is found under dry blocks on the ground in the dark cave.

Distribution. Only known from the type locality ( Fig. 50 ).

Figures

FIGURE 50. Locality records of tetrablemmid species in China.

FIGURES 38–45. Tetrablemma nandan sp. nov. 38–39 Male prosoma (38 dorsal, 39 lateral view); 40 Female opisthosoma, ventral view; 41 Male left chelicera, anterior view; 42 Female left chelicera, anterior view; 43 Leg I of male, retrolateral view; 44–45 Male left pedipalp (44 prolateral, 45 retrolateral view). Scales: 0.1 mm

FIGURES 46–49. Tetrablemma nandan sp. nov. 46–47 Female prosoma (46 dorsal, 47 lateral view); 48 Female opisthosoma, ventral view; 49 Female genital area (KOH-treated), ventral view. Scales: 0.1 mm