Tropizodium siam sp. nov.

Figs 1–6, 8, 10–11

Type material. Holotype, 3: THAILAND, Chiang Mai Province: Chiang Mai City, Chiang Mai University, Mae Hia Campus, Mae Hia, 350 m, 1 April 1987, leg. P.J. Schwendinger (MHNG, PD-1542) . Paratypes: 1Ƥ, data as holotype (MHNG, PD-1542) . 23, 2Ƥ, Mae Rim District, Mae Sa, 600 m, 14 November 1990, leg. P.J. Schwendinger (MHNG, PD-8846; TNHM).

Diagnosis. Males of T. siam sp. nov. closely resemble those of T. serraferum comb. nov. but can be distinguished by the median apophysis of the male palp which is characterized by an elongated and more prominent retrolateral folds (Figs 3, 5). Females are easily recognized by the anterior pentagonal epigynal socket (Figs 6, 10–11) and the presence of paired membranous bursae (Figs 10–11).

Etymology. The specific epithet is a noun in apposition and refers to the former name of Thailand.

Description. Male (holotype): Total length 1.84; prosoma 0.96 long, 0.60 wide. Leg measurements: leg I 3.04 (0.80, 0.30, 0.68, 0.74, 0.52); leg II 2.58 (0.66, 0.28, 0.52, 0.64, 0.48); leg III 2.54 (0.62, 0.28, 0.50, 0.70, 0.44); leg IV 3.74 (0.96, 0.32, 0.88, 1.02, 0.56). Eyes: ALE 0.14; other eyes 0.06.

Coloration and pattern (Fig. 1). Carapace pale yellow, with black ocular region, and paired, brownish patches situated at posterior margin of pars cephalica; legs pale, almost white. Opisthosoma: dorsum reddish brown, mottled with numerous pale markings; venter and lateral sides pale yellow.

Palp (Figs 3–5). Palpal tibia relatively short, subcylindrical. RTA almost reaching tip of cymbium, broad at base, distal half slender, sinuous, subterminally abruptly bent ectad, apex blunt. Cymbium with one large apical seta and few smaller pectinated setae on prolateral surface. Embolic base triangular, situated meso-prolaterally; embolus heavily sclerotized, lanceolated, apex slender, located underneath MA. MA bifid, with rostrated apex, prolaterally with triangular subapical flange, retrolaterally with two relatively broad excrescences.

Female (paratype, MHNG, PD-1542): Total length 2.86; prosoma 1.12 long, 0.82 wide. Leg measurements: leg I 3.10 (0.84, 0.34, 0.70, 0.72, 0.50); leg II 2.74 (0.70, 0.32, 0.52, 0.76, 0.44); leg III 2.76 (0.74, 0.32, 0.52, 0.70, 0.48); leg IV 4.10 (1.04, 0.38, 0.92, 1.18, 0.58). Eyes: ALE 0.12; other eyes 0.06.

Coloration and pattern (Fig. 2). Carapace pale yellow, with black ocular region and brown reticulum on pars cephalica; legs pale yellow. Opisthosoma: dorsum dark brown; venter and lateral sides pale yellow.

Genitalia (Figs 6, 8, 10–11). Epigynal region weakly sclerotized, with anteriorly situated pentagonal chamber; its posterior margin concave. Insemination ducts originating anteriorly on inner surface of epigynal chamber, curved, connected to subspherical spermathecae. Fertilization ducts acicular, elongated. Paired membranous bursae attached to posterior corner of chamber, directed ventrally and curving dorsally.

Natural history. Types of T. siam sp. nov. were collected in deciduous forests between 350 and 600 m asl.

Distribution. Northern Thailand (Chiang Mai Province).