Stygotorrenticola, Pešić, Vladimir & Gerecke, Reinhard, 2014

Pešić, Vladimir & Gerecke, Reinhard, 2014, Water mites from caves of the Ha Giang province, northern Vietnam (Acari: Hydrachnidia), Zootaxa 3774 (4), pp. 367-380 : 371

Genus Stygotorrenticola gen. nov.

Diagnosis. Ocular pigment absent; shoulder platelets fused to the dorsal plate, frontal platelets fused to each other to form a narrow, transverse platelet; Cxgl-4 subapical; suture lines Cx-I/ -II complete, not meeting in the medial line, but separately ending at anterior genital field margin; suture line Cx-II/III developed only in lateral quarter; suture lines of Cx-IV not visible; excretory pore on the limit of primary sclerotization near posterior idiosoma margin; P-2 with a stout, pointed peg-like seta on a pointed, anteriorly directed distoventral projection; P-3 with similar seta on a pointed projection in the centre of segment; P-4 slender, ventral margin with 5 setae; chelicera basal segment inflated in the centre, claw short and curved; gnathosomal rostrum shortened, ventrally not evidently set off from base.

Type species. Stygotorrenticola coniseta sp. nov.

Etymology. “ stygo ” (meaning adapted to living underground and referring to the River Styx in Greek and Roman mythology) is prefixed to the existing genus name Torrenticola .

Remarks. Stygotorrenticola differs from all other torrenticolid genera in (1) absence, in both sexes, of a medial suture Cx-II+III, and (2) presence of strong, peg-like setae on ventral protuberances of P-2/-3. The genus is similar to Monatractides in the stout gnathosoma with short rostrum, but to Torrenticola in the enlarged, U-shaped gnathosomal bay and the presence of distoventral projections on P-2/-3.

Possibly, the development of peg-like palp setae (probably of sensory function) can be considered a compensation for light sensitivity due to reduction of lateral eyes.