Torrenticola nipponica (Enami, 1940)

Pesic, Vladimir, Semenchenko, Ksenia A. & Lee, Wonchoel, 2013, Torrenticolid water mites from Korea and the Russian Far East, ZooKeys 299, pp. 21-48 : 29-32

Torrenticola nipponica (Enami, 1940) Figs 5, 6, 7 G–I

Atractides nipponicus Enami, 1940: 221.

Material examined.

SOUTH KOREA: CR1 Seoul, Dobong stream, 37°41.262'N, 127°01.706'E, 19 m asl., 7.x.2012, Pešić & Choi 2/0/0 (mounted, NIBRIV0000268848). RUSSIA: Primory Territory, Partizansky District, Partizanskay River basin, Tigrovaya River, 43°11.401'N, 133°12.660'E; depth 30 cm below the sediment surface; substrate: cobbles, pebbles, sand; 12.vi.2010, Semenchenko & Sidorov 2/2/0 (mounted, IBSS).

Morphology.

General features. Idiosoma roundish; dorsal shield with colour pattern as illustrated in Figs 7G-I; Cxgl-4 subapical; excretory pore and Vgl-2 slightly away from the line of primary sclerotization; gnathosoma deep, rostrum shorter than depth of gnathosomal base (Fig. 5D); palp robust and compact, P-2 longer than P-4, P-2 and P-3 ventrodistal projection pointed towards distal, P-4 with well developed ventral tubercles bearing one long and three short setae (Figs 5E-F, 6C). Male: Medial suture line of Cx-II+III short; suture line of Cx-IV medially starting from posterior margin of genital field (Fig. 2B); ejaculatory complex normal in shape (Fig. 5C). Female: Suture of Cx-IV curved (Fig. 2C); genital field pentagonal in shape.

Measurements. Male (from South Korea, n = 2; in parentheses specimens from Russia, n = 2) Idiosoma (ventral view: Fig. 5B) L 694-819 (740-755), W 478-534 (508-544); dorsal shield (Figs 5A, 7G-H) L 584-675 (636-670), W 410-469 (422-476), L/W ratio 1.42-1.44 (1.4-1.5); dorsal plate L 556-643 (594-614); shoulder plate L 178-206 (178-188), W 56-61 (59-60), L/W ratio 3.0-3.4 (2.96-3.18); frontal plate L 113-125 (121-125), W 45-50 (46-47), L/W ratio 2.4-2.5 (2.56- 2.72); shoulder/ frontal plate L ratio 1.56-1.67 (1.46-1.5). Gnathosomal bay L 148-153 (132-141), Cx-I total L 278-294 (284-286), Cx-I mL 129-141 (145-165), Cx-II+III mL 69-91 (79-92); ratio Cx-I L/Cx-II+III mL 3.2-4.0 (3.1-3.6); Cx-I mL/Cx-II+III mL 1.55-1.87 (1.57-2.08). Genital field L/W 156-181/117-133 (168-172/125-132), L/W ratio 1.33-1.36 (1.26-1.38); ejaculatory complex L 231 (224-251); distance genital field-excretory pore 131-178 (138-145), genital field-caudal idiosoma margin 183-231 (172-205). Gnathosoma vL 273-303 (277-297); chelicera total L 319-347 (323-343); palp total L 279-316 (284-291), dL: P-1, 34-37 (33-36); P-2, 92-101 (92-95); P-3, 52-63 (51-59); P-4, 82-93 (82-92); P-5, 19-22 (17-18); P-2/P-4 ratio 1.09-1.13 (1.03-1.12).

Female (from Russia, n = 2). Idiosoma (ventral view: Fig. 6B) L 860-867, W 629-635; dorsal shield (Figs 6A, 7I) L 723-782, W 502-544, L/W ratio 1.44; dorsal plate L 680-731; shoulder plate L 211-214, W 66-73, L/W ratio 2.92-3.2; frontal plate L 128-139, W 59-64, L/W ratio 2.16- 2.17; shoulder/frontal plate L ratio 1.54-1.65. Gnathosomal bay L 168-178, Cx-I total L 303-310, Cx-I mL 132-145, Cx-II+III mL 30-40; ratio Cx-I L/Cx-II+III mL 7.75-10.1; Cx-I mL/Cx-II+III mL 3.63-4.4. Genital field L/W 185-195/172-178, L/W ratio 1.04-1.13; distance genital field-excretory pore 208-210, genital field-caudal idiosoma margin 297-310. Gnathosoma vL 330-336; chelicera total L 420; palp total L 341-345, dL: P-1, 41-43; P-2, 115-116; P-3, 65-67; P-4, 100-102; P-5, 18-19; P-2/P-4 ratio 1.13-1.16.

Remarks.

The male specimens from South Korea and Russia fit the description of Torrenticola nipponica (Enami, 1940) which was based on one male and seven females from River Inôzava, Uzi region in Japan ( Enami 1940). However, as the type material was probably lost (not found in the arachnid collection in the National Museum of Nature and Science, Tokyo, Hirotsugu Ono pers. comm.) additional sampling and selection of a neotype from the locus typicus is necessary to guarantee taxonomic stability of Torrenticola nipponica . In the original description, Enami (1940) compared Torrenticola nipponica with Torrenticola brevirostris (Halbert, 1911), a species which differs in the gnathosomal rostrum not distinctly set off from the gnathosomal base, P-2 shorter than P-4, the suture line of Cx-IV starting at right angle from the genital field, the excretory pore and Vgl-2 more distanced from the line of primary sclerotization and the genital field in male is less elongated.

Habitat.

A permanent shaded sandy/bouldary stream at low elevations (Fig. 14A); the specimens from Russia were collected from interstitial waters.

Distribution.

Japan (Uzi region- Enami, 1940), South Korea (Chindo Island - Chung & Kim 1995; present study). New for the fauna of Russia.