Hersilia thailandica, Pakawin Dankittipakul & Tippawan Singtripop, 2011

Pakawin Dankittipakul & Tippawan Singtripop, 2011, The spider genus Hersilia in Thailand, with descriptions of two new species (Araneae, Hersiliidae), Revue suisse de Zoologie 118 (2), pp. 207-221 : 216-218

Hersilia thailandica sp. n.

Figs 20-24

HOLOTYPE: MHNG-PDC-65465444442244741976-109 ; Thailand, Chiang Mai Province, Mae Rim District, Queen Sirikit Botanic Garden , 600- 700 m, on a tree trunk in degraded forest in front of museum building; 1 male; 6.- 13.10.2006; leg. P. Dankittipakul.

PARATYPES: MHNG-PDC-12546554574875655 ; same data as for holotype; 3 males.

ETYMOLOGY: The specific name is an adjective (“thailandicus, -a, -um”) and refers to the presence of this species in Thailand.

DIAGNOSIS: Hersilia thailandica sp. n. belongs to the pectinata -group, which is easily recognized by the male palpal patella being short, and the palpal tibia with an elevated dorsal projection carrying a group of long erect spines ( Figs 21-23 ). The new species is most similar to H. pectinata Thorell, 1895 from Burma in the similar male palp with an enlarged, ovoid bulbus, an elongated, curved embolus thickening and a Tshaped TA. Hersilia thailandica sp. n. can be distinguished from H. pectinata by: seven large erected spines on palpal tibia directed anteriad ( Figs 21, 23 ) instead of laterad (almost perpendicular to the axis of the tibia in H. pectinata ); the embolus terminally abruptly bending distad, gradually narrowing towards its bluntly pointed apex ( Figs 20, 22 ); the ovoid bulbus with enlarged tubular TA ( Fig. 22 ) instead of being a reniform plate.

DESCRIPTION

Male holotype: Prosoma 2.8 long, 2.6 wide; opisthosoma 4.4 long, 2.8 wide. PLS 7.3 long, bS 1.1 long, tS 6.2 long.

Prosoma: Prosoma pear-shaped, posteriorly distinctly disc-shaped; ocular region relatively low; clypeus slightly shorter than ocular region; chelicerae elongated, twice as long as wide; sternum triangular, anterior margin with shallow median incision.

Eye size and interdistances: Eyes almost subequal; AME slightly larger than PME; ALE = PLE <AME; eye ratio: 1.0: 0.82: 0.84: 0.96. AME = 1.0; AME-AME = 0.78; AME-ALE = 0.98; PME = 1.0; PME-PME = 0.68; PME-PLE = 0.72.

Opisthosoma: Opisthosoma longer than wide, widest behind the middle, anterior margin almost straight, posteriorly with triangular anal tubercle; dorsum with four pairs of large circular DMP, second pair slightly larger, others subequal; VMP numerous, forming parallel longitudinal lines but distance distinctly narrower posteriorly.

Spinnerets: PLS elongated, twice as long as opisthosoma; other spinnerets not visible in dorsal view.

Leg measurements: I, 20.24 (4.96, 1.92, 5.02, 7.58, 0.76); II, 20.7 (5.42, 0.98, 5.44, 7.98, 0.88), III, 4.52 (1.46, 0.42, 0.98, 1.12, 0.54), IV 11.7 (4.46, 0.8, 2.58, 3.08, 0.78).

Male palp ( Figs 20-24 ): Tibia short, dorsally with elevated projection carrying seven long erect spines directed anteriad ( Fig. 23 ). Cymbium with three stout apical spines. Bulbus large, ovoid; lateral borders rounded. Embolus broad, heavily pigmented, without accessory process, originating postero-medially, curving in anticlockwise direction (on left palp), terminally abruptly bending distad, gradually narrowing towards it bluntly pointed apex ( Figs 20, 22 ). TA developed as a large elongated prong, its base broad, with a retro-basal ridge, narrowing to form a tubular stalk and abruptly bending mesad ( Figs 20, 22 ), apex spoon-shaped, curling inwards ( Fig. 24 ).

Female: Unknown.

DISTRIBUTION: Known only from the type locality in Chiang Mai Province (Fig. 32).

Figures

FIGS 20-21 Hersilia thailandica sp. n., holotype. (20) Left male palp, ventral view. (21) Ditto, retrolateral view. Scale lines = 1.0 mm.

FIGS 22-24 Hersilia thailandica sp. n., holotype. (22) Left male palp, proventral view. (23) Ditto, dorsal view. (24) Apex of TA, prolateral view. Scale lines = 1.0 mm.