Torrenticola thailandicus, Pesic & Smit, 2009

Pesic, Vladimir & Smit, Harry, 2009, Water mites of the family Torrenticolidae Piersig, 1902 (Acari: Hydrachnidia) from Thailand, Part I. The genera Torrenticola Piersig, 1896, Neoatractides Lundblad, 1941 and Pseudotorrenticola Walter, 1906, Zootaxa 1982, pp. 38-62 : 47-50

Torrenticola thailandicus sp. nov.

( Figs. 42–55)

Type series. Holotype: male, dissected and slide mounted in Hoyer's fluid. fast flowing stream crossing road to Den Ya Kat Station, alt. 410 m, Chiang Dao NP, 23.xi.2007, 19° 19.735 N 98° 56.201 E, leg. Smit. Paratypes: two males, two females, same station and date, one male and two females dissected and slide mounted in Hoyer's fluid.

Further material. Thailand, stream downstream of Siriphum Waterfall , Doi Inthanon NP, alt. 1300 m, 26.xi.2007, 18° 31.532 N 98° 39.091 E, leg. Smit (1/0/0), dissected (one palp missing) and slide mounted in Hoyer's fluid .

Diagnosis. Idiosoma dimension small (L/W males 669-681/456-453, females 681-700/488-538); medial suture line of Cx-2+3 relatively long in male; ventral projections on P-2 slightly pronounced.

Description. Male (holotype, in parentheses measurements of the paratype): Idiosoma (ventral view: Fig. 43) L 681 (669), W 456 (463); dorsal shield ( Fig. 42) L 513 (519), W 394 (409), L/W ratio 1.3 (1.27); dorsal plate 469 (475); shoulder plate L 191 (206), W 63 (66), L/W ratio 3.1 (3.1); frontal plate L 117 (125), W 56 (55), L/W ratio 2.1 (2.3); shoulder/frontal plate L ratio 1.6 (1.7); gnathosomal bay L 128 (122), Cx-1 total L 297 (288), Cx-1 medial L 169 (166), Cx-2+3 medial 100 (102); ratio Cx-1 L/Cx-2+3 medial L 3.0 (2.8); Cx-1 medial L/Cx-2+3 medial L 1.7 (1.6); genital field L/W 125 (122)/91 (88), L/W ratio 1.4 (1.4), ejaculatory complex ( Fig. 44-45) L 150 (150); distance genital field–excretory pore 97 (105), genital field–caudal idiosoma margin 141 (145); capitulum ventral L 275 (275); chelicera L 319 (323); palp ( Fig. 49) total L 237 (227), L: P-1 27 (24), P-2 76 (74), P-3 52 (49), P-4 67 (65), P-5 15 (15); %L: P-1 11.4 (10.6), P-2 32.1 (32.6), P-3 21.9 (21.6), P-4 28.3 (28.6), P-5 6.3 (6.6); P-2/P-4 ratio 1.14 (1.14); ventral projections on P-2 and P-3 only slightly pronounced, ventral protuberances of P-4 forming an unique tip bearing one long and three short hairs.

Female (based on two paratype specimens): Idiosoma (ventral view: Fig. 48) L 681-700, W 488-538; dorsal shield ( Fig. 47) L 531-581, W 413-456, L/W ratio 1.3; dorsal plate 493-538; shoulder plate L 172-178, W 63-65, L/W ratio 2.7; frontal plate L 122-131, W 50-56, L/W ratio 2.3-2.4; shoulder/frontal plate L ratio 1.3- 1.5; gnathosomal bay L 141-150, Cx-1 total L 294-306, Cx-1 medial L 153-156, Cx-2+3 medial 28-30; ratio Cx-1 L/Cx-2+3 medial L 9.8-10.9; Cx-1 medial L/Cx-2+3 medial L 5.1-5.6; genital field L/W 147/131-134, L/W ratio 1.1; distance genital field–excretory pore 134-147, genital field–caudal idiosoma margin 194-208; capitulum ( Fig. 46) ventral L 278-291; chelicera L 341-366; palp ( Fig. 50) total L 229-235, L and %L (in parentheses): P-1 24-26 (10.5-11.1), P-2 77-80 (33.6-34.0), P-3 49-50 (20.9-21.8), P-4 64-65 (27.7-28.0), P-5 14-15 (6.1-6.4); P-2/P-4 ratio 1.2; shape and setation as in male.

In addition we give measurements of the male specimen from Sirphium Waterfall: Idiosoma (ventral view: Fig. 52) L 663, W 463; dorsal shield ( Fig. 51) L 525, W 400, L/W ratio 1.3; dorsal plate 481; shoulder plate L 175, W 69, L/W ratio 2.5; frontal plate L 128, W 53, L/W ratio 2.4; shoulder/frontal plate L ratio 1.4; gnathosomal bay L 122, Cx-1 total L 297, Cx-1 medial L 175, Cx-2+3 medial 81; ratio Cx-1 L/Cx-2+3 medial L 3.7; Cx-1 medial L/Cx-2+3 medial L 2.2; genital field L/W 138/97, L/W ratio 1.4, ejaculatory complex ( Fig. 53) L 184; distance genital field–excretory pore 111, genital field–caudal idiosoma margin 144; capitulum ( Fig. 54) ventral L 266; chelicera L 297; palp total L 225, L and %L (in parentheses): P-1 24 (10.7), P-2 74 (32.9), P-3 47 (20.9), P-4 65 (28.9), P-5 15 (6.7); shape and setation as in Fig. 55.

Discussion. Due to sub-apical Cxgl-4, one (of 4) P-4 ventral setae long, a long rostrum, a similar extension of Cx-4 behind the genital flaps and the shape of the ejaculatory complex, Torrenticola thailandicus sp. nov. is closely related to Torrenticola bhutana Pesic & Smit. The male of T. thailandicus sp. nov. differs from T. bhutana (in parentheses data taken from Pesic & Smit 2007) in the minor idiosoma and gnathosoma dimensions (e.g. idiosoma L/W 875/625, genital field L 172, capitulum L 327, palp total L 287), the longer medial suture line of Cx-2+3 (61m in T. bhutana ) and smaller dimensions of the ejaculatory complex (253m in T. bhutana ). Males and females of T. thailandicus sp. nov. have less slender palps with shortened ventrodistal projection on P-2 than that of T. bhutana . T. bhutana has the P-2 more slender and relatively longer (P-2 relative L>34.0 in male,>35.0 in female). In both sexes ventral protuberances of P-4 form a unique tip in T. thailandicus sp. nov. (ventral protuberances ending in two tips separated from each other by a concave interspace in T. bhutana ). Females can be distinguished in their minor idiosoma and gnathosoma dimensions (e.g., T. bhutana idiosoma L 938, dorsal shield L 756, genital field L 197, palp total L 306) and a slightly shorter medial suture line of Cx-2+3. Females differ from males in degree of the extension of Cx-4 behind the genital flaps (compare Figs. 43 and 48). The specimen from Sirphium Waterfall has two setae on distoventral surface of P-2 ( Fig. 55), a character found only as an individual aberration.

Etymology. The species is named after Thailand.

Distribution. Known only from the two localities in Thailand.

Biology. Torrenticola thailandicus sp. nov. is probably a rhitrobiontic species.