Trachelas L. Koch, 1866

Zhang, Feng, Fu, Jian-Ying & Zhu, Ming-Sheng, 2009, A review of the genus Trachelas (Araneae: Corinnidae) from China, Zootaxa 2235, pp. 40-58 : 41-42

Trachelas L. Koch, 1866

Trachelas L. Koch, 1866: 2 . Platnick & Shadab, 1974a: 3; 1974b: 3; Dondale & Redner, 1982: 123. Song, Zhu & Chen, 2001: 323. Deeleman-Reinhold, 2001: 393. Bosselaers, Urones, Barrientos & Alberdi, 2009: 16.

Type species: Trachelas minor O. Pickard-Cambridge, 1872 , by original designation.

Diagnosis (Asian Trachelas only, especially Chinese species). Typical species of Trachelas can be distinguished from other Corinnidae genera by the spineless legs (but often with cusps on male leg I, even leg II), the straight anterior margin of the clypeus, the presence of chilum between the chelicerae, and the often granulated and convex bulging carapace. Also by the anterior legs more robust than posterior legs, especially in males ( Bosselaers et al. 2009); by the female posterior median spinnerets having four to five cylindrical gland spigots in two rows ( Bosselaers & Jocqué 2002). The Eurasian Trachelas (including the type species, T. minor ) presumably has close affinities with the Oriental genus Utivarachna on the basis of potentially derived genital characters: the vulva is complex, with conspicuously coloured ducts connecting the copulatory openings with the anterior thin-walled sacs (called spermatheca 2 by von Engelhardt, 1910, also called bursa by Deeleman-Reinhold, 2001); male palp generally simple, with embolus, sometimes with conductor or tegular apophysis, tibia with or without a retrolateral apophysis, sometimes with a patellar apophysis. Trachelas is distinguished from Utivarachna by the smoothly curved sides of the cephalic area without an invagination behind the cephalic region; the rounded, widely truncate posterior carapace border; the shorter endites and labium; the posteriorly rounded sternum; the conspicuous, anteriorly (most species) or posteriorly placed copulatory openings ( Deeleman-Reinhold, 2001). Many characters distinguish Eurasian Cetonana from most Trachelas : more pronounced precoxal triangles, leg cusps in females, large anterior median eyes, and a male bulbus covering only part of the ventral side of the cymbium ( Grimm 1986).

Description (Asian Trachelas only, especially Chinese species). Total length 3.00–6.00. Carapace shiny orange-brown to dark red, and densely covered with tiny granulations in most species (carapace of T. alticolus without granulations); ovoid in dorsal view, somewhat truncated at posterior margin, convex, highest between fovea and posterior row of eyes; fovea shallow, usually indistinct, located on posterior slope of carapace, longitudinal, short line-shaped or somewhat round pit-shaped. Eyes moderately large, nearly uniform in size; AER slightly recurved, with AME slightly closer to ALE than to each other; PER recurved, with eyes uniformly spaced or with PME closer to PLE than to each other; PER slightly longer than anterior row. Chelicerae dark orange, stout, covered with minute granulations; usually armed with three promarginal teeth and two retromarginal teeth. Endites longer than wide, not constricted at middle on lateral margin and without a transverse or oblique depression, the apex rounded. Labium slightly wider than long. Sternum smooth, rounded posteriorly extending between the fourth coxae; with intercoxal triangles. First legs much stouter than the others; legs not armed with spines. Legs I and II of males sometimes with rows of small black cusps on the tibia, metatarsus and tarsus. Tarsal scopulae and claw tufts present. Trochanter without ventral notch at distal end. Abdomen pale yellow, light gray or dark gray; ovoid, often with two pairs of sigilla and scattered light spots on dorsum, without dorsal, epigastric, and ventral scuta. Terminal segment of the posterior spinnerets very short, hemispherical, often indistinct. Femur of male palp often largely concave on distal ventral side; some species with long patellar apophysis; tibia of male palp as long as wide or slightly longer, with small or long retrolateral apophysis; tegulum convex, rounded at base, sometimes with distinct sperm ducts; with or without terminal apophysis; embolus variable, short, erect, tapered, thick or straight, situated distally or prolaterally on tegulum; with large conductor subdistally, or pointed functional conductor distally, or without conductor; tegular apophysis small, hook-shaped, situated on the upper part of tegulum, or without tegular apophysis. Epigynum with rounded, flat, or convex plate, with or without small atrium and atrial hood; copulatory openings round, kidney-shaped or funnel-like; bursae (we followed Deeleman-Reinhold, 2001) and spermathecae terminating in two branches of different lengths and widths; spermathecae arising at posterior end of epigynum, with connecting copulatory ducts thin and long; bursae arising at lateral or central part of epigynum, with connecting copulatory duct relatively wider and shorter.