Torrenticola brevirostris (Halbert, 1911)

Pesic, Vladimir, Semenchenko, Ksenia A. & Lee, Wonchoel, 2013, Torrenticolid water mites from Korea and the Russian Far East, ZooKeys 299, pp. 21-48 : 22-23

Torrenticola brevirostris (Halbert, 1911) Figs 1, 7A

Atractides brevirostris Halbert, 1911: 16.

Material examined.

SOUTH KOREA: CR9 Ne myeon Mt, Naebyeansan NP, stream near Naebyeansan Info Center, 35°38'25.623"N, 126°34'53.1438"E, 10.x.2012, Pešić & Choi 1/0/0 (mounted, NIBRIV0000268844).

Morphology.

Male. General features. Idiosoma roundish; Cxgl-4 subapical; posterior suture line of Cx-IV starting at right angle from genital field; excretory pore and Vgl-2 away from the line of primary sclerotization (Fig. 1B); ejaculatory complex conventional in shape (with well developed anterior keel and proximal arms); gnathosomal rostrum shortened, ventrally not evidently set off from gathosomal base (Fig. 1D); P-2 shorter than P-4, P-2 ventral margin slightly convex; P-4 stout, with well developed ventral tubercles (Fig. 1C).

Measurements. Idiosoma (ventral view: Fig. 1B) L 731, W 500; dorsal shield (Fig. 1A, 7A) L 598, W 441, L/W ratio 1.36; dorsal plate L 544; shoulder plate L 175-177, W 78-83, L/W ratio 2.1-2.3; frontal plate L 130-131, W 66-67, L/W ratio 1.9-2.0; shoulder/frontal plate L ratio 1.34-1.36. Gnathosomal bay L 119, Cx-I total L 284, Cx-I mL 164, Cx-II+III mL 93; ratio Cx-I L/Cx-II+III mL 3.05; Cx-I mL/Cx-II+III mL 1.8. Genital field L/W 152/119, ratio 1.28; ejaculatory complex L 222; distance genital field-excretory pore 127, genital field-caudal idiosoma margin 200. Gnathosoma vL 266; chelicera total L 292; palp total L 296, dL: P-1, 26; P-2, 87; P-3, 66; P-4, 89; P-5, 28; P-2/P-4 ratio 0.98.

Remarks.

The single male specimen examined from a stream in Naebyeansan National Park fits well the original description of Torrenticola brevirostris . The differences are found in a minor idiosoma and gnathosoma dimensions and a more shallow gnathosoma with a relatively less shortened rostrum compared with the populations from the Western Palaearctic (see: Cicolani and Di Sabatino 1990, Pešić et al. 2006, Di Sabatino et al. 2010). In the shape of gnathosoma the specimen from Korea matches the description of Torrenticola brevirostris from Gifu Prefecture in Japan ( Imamura 1953). This may suggest that there is some degree of genetic isolation between the populations from the Far East and populations from the Western Palaearctic. However, understanding of these populations is not possible without additional material and probably will require the application of molecular techniques.

Habitat.

A permanent sandy/bouldary stream, shaded by riparian vegetation (Fig. 14B).

Distribution.

Palaearctic. New for the fauna of Korea.