Otacilia bifurcata, Dankittipakul, Pakawin & Singtripop, Tippawan, 2014

Dankittipakul, Pakawin & Singtripop, Tippawan, 2014, New species and new records of the spider genus Otacilia Thorell, 1897 (Araneae, Corinnidae) from Southeast Asia, Revue Suisse De Zoologie 121, pp. 383-394 : 383

Otacilia bifurcata sp. n. Figs 17-23

HOLOTYPE: ♂; Thailand, Chaing Mai Province, Fang District, Doi Ankhang, 1450 m; 24.VIII.1990; leg. P.J. Schwendinger (MHNG).

PARATYPES: 5♂; same data as for holotype (MHNG).

DIAGNOSIS: Otacilia bifurcata sp. n. can be easily distinguished from its congeners by the triangular basal spike on the embolus of the male palp (Figs 18-20), and by retrolateral and dorsal tibial apophyses being subequal in size (Figs 20-22).

RELATIONSHIP: Males of this new species resemble those of O. zebra Deeleman- Reinhold, 2001 (RMNH, examined) in having two large tibial apophyses on the male palp, but in O. zebra the retrolateral tibial apophysis is significantly smaller. Both species also differ by their body color pattern.

ETYMOLOGY: The specific epithet refers to the presence of two elongated tibial apophyses on the male palp.

DESCRIPTION OF MALE (HOLOTYPE): Total length 3.4; prosoma 1.6 long, 1.3 wide; opisthosoma 1.8 long, 1.2 wide.

Prosoma: Prosoma broadest between coxae I and II, narrowed in cephalic region in front of coxae I; in profile highest in front of fovea, gradually sloping posteriorly. Carapace reddish brown, with dark brown striae radiating from deep longitudinal fovea. Sternum yellow, with distinctly dark brown margin, subovoid, almost as long as wide, posteriorly bluntly pointed, devoid of distinctive projection between leg coxae. Labium wider than long, anterior margin slightly curved. Palpal coxae subrectangular, with thin apical scopulae. Cheliceral fang slender, moderately long; three small teeth each on promarginal and retromarginal fang grooves; frontal surface with two slender bristles.

Eyes: Eight eyes arranged in two rows, occupying almost entire attenuated cephalic region; AER straight, PER slightly recurved; eyes subequal in size, with pale and circular PME, other eyes circled with black, not clearly outlined ring. Eye sizes and interdistances: AME 0.10, ALE 0.10, PME 0.08, PLE 0.09; AME-AME 0.16, AME-ALE 0.14, PME-PME 0.20, PME-PLE 0.12, ALE-PLE 0.10; MOQ 0.36 long, anterior width 0.26, posterior width 0.28.

Legs: Leg formula 4123. Measurements: leg I 8.2 (1.9, 2.9, 1.8, 1.6); leg II 5.5 (1.5, 1.8, 1.2, 1.0); leg III 4.9 (1.3, 1.5, 0.9, 1.2); leg IV 9.9 (2.5, 2.9, 2.3, 2.2). All coxae pale yellow; anterior femora dark brown, posterior ones yellowish brown; other leg segments yellow. Spination: anterior femora armed with two dorsal bristles situated in proximal half, and with one distal bristle; posterior femora with two short bristles widely separated from each other; femur I with four elongated prolateral spines; tibia I with seven pairs of ventral spines; femur II with two elongated prolateral spines; tibia II with six pairs of ventral spines; metatarsi I and II with four pairs of ventral spines; femora III and IV lacking prolateral spines; other leg segments devoid of large spines.

Opisthosoma: Elongate-ovoid, sparsely clothed with fine pubescence. Dorsal scutum absent, but with conspicuous chitinized area extending over four fifths of dorsal area. Dorsum greenish brown, with yellow pigment shining through. Venter pale, without markings.

Palp (Figs 17-23): Femur with translucent ridge and a small projection ventrally (Figs 17, 22-23). Retrolateral and dorsal tibial apophyses represented by enlarged, triangular prong with slender distal half (Figs 20-22). Dorsal tibial apophysis slightly shorter than retrolateral one. Tegulum ovoid, with sigmoid sperm duct located distally (Fig. 20). Embolus hook-shaped, heavily sclerotized, originating distoprolaterally, its sharp apex pointing retrolaterad and basally carrying a sharply pointed retrolateral spike (Figs 18-20). Conductor membranous, rectangular, situated posterior to embolus (Fig. 20).

FEMALE: Unknown.

NATURAL HISTORY: All type specimens of O. bifurcata sp. n. were collected by sifting thick decomposing leaf litter and other organic humus in an evergreen hill forest.

DISTRIBUTION: Known only from the type locality in northern Thailand.