Torrenticola sp.

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 : 53-57

Torrenticola sp.

( Figs. 65–82)

Material. Thailand: stream crossing road to Doi Chiang Dao, NP Chiang Dao, alt. 417 m , 25.xi.2007, 19° 23.304 N 98° 55.780 E, leg. Smit (0/1/0), dissected and slide mounted in Hoyer's fluid; Pong Creek crossing road to Muang Kong, Doi Chiang Dao, alt. 477 m , 22.xi.2007, 19° 24.774 N 98° 55.127 E, leg. Smit (1/0/0), dissected and slide mounted in Hoyer's fluid; stream W of Bankrang Camp, Kaeng Krachan NP , 30.xi.2007, 12° 48.106 N 99° 26.786 E, leg. Smit (1[juvenile]/0/0); Pong Creek crossing road to Muang Kong, Doi Chiang Dao, alt. 477 m , 22.xi.2007, 19° 24.774 N 98° 55.127 E, leg. Smit (1[juvenile]/0/0); River at km. 13, alt. 465 m ,

Doi Inthanon NP, 25.xi.2007, 18° 31.532 N 98° 39.091 E leg. Smit (13[juveniles {characterized by the caudal position of the excretory pore and weakly developed secondary chitinization} and semiadults {characterized by the less developed secondary chitinization than adults}]/ [1adult]/1), two males (one juvenile and one semiadult specimens) and one ovigerous female dissected and slide mounted in Hoyer's fluid.

Morphology. Male (semiadult specimen from River at km. 13, in parentheses juvenile specimen from Pong Creek): Idiosoma (ventral view: Fig. 66) L 656 (575), W 569 (481); dorsal shield ( Fig. 65) L 569 (550), W 481 (356), L/W ratio 1.2 (1.5); dorsal plate 544 (513); frontal plate L 121 (119), W 44 (44), L/W ratio 2.8 (2.7); gnathosomal bay L 138 (153), Cx-1 total L 269 (294), Cx-1 medial L 131 (141), Cx-2+3 medial 66 (63); ratio Cx-1 L/Cx-2+3 medial L 4.1 (4.7); Cx-1 medial L/Cx-2+3 medial L 2.0 (2.2); genital field L/W 138 (144)/106 (113), L/W ratio 1.3 (1.3), ejaculatory complex ( Fig. 76) L 186 (197); distance genital field–excretory pore 113 (72), genital field–caudal idiosoma margin 175 (94); capitulum ventral (Fig. 59) L 291 (300); chelicera L 356 (356); palp ( Figs. 67-68) total L (318), L: P-1 35 (37), P-2 97 (106), P-3 58 (59), P-4 88 (98), P-5 20 (20); %L: P-1 12.0 (11.6), P-2 33.3 (33.3), P-3 19.9 (18.6), P-4 30.2 (30.8), P-5 (62.9); P-2/P-4 ratio 1.1 (1.08); P-4 with ventral denticles, ventral tubercles well developed ( Figs. 67-68).

Female (adult specimen from River at km. 13, in parentheses juvenile specimen from stream crossing road to Doi Chiang Dao): Idiosoma (ventral view: Fig. 70) L 881 (625), W 718 (531); dorsal shield ( Fig. 69) L 762 (575), W 594 (419), L/W ratio 1.3 (1.4); dorsal plate 716 (544); frontal plate L 175 (153), W 67 (56), L/ W ratio 2.6 (2.7); gnathosomal bay L 198 (188), Cx-1 total L 372 (344), Cx-1 medial L 172 (156), Cx-2+3 medial 41 (23); ratio Cx-1 L/Cx-2+3 medial L 9.1 (15.0); Cx-1 medial L/Cx-2+3 medial L 4.2 (6.8); genital field L/W 175 (171)/153 (157), L/W ratio 1.14 (1.16); distance genital field–excretory pore 200, genital field–caudal idiosoma margin 284; capitulum ( Fig. 73) ventral L 400 (365); chelicera L 484 (425); palp ( Figs. 71-72) total L 383 (360), L: P-1 47 (39), P-2 129 (118), P-3 73 (74), P-4 111 (106), P-5 23 (23); %L: P-1 12.3 (10.8), P-2 33.7 (32.8), P-3 19.1 (20.6), P-4 29.0 (29.4), P-5 6.0 (6.4); P-2/P-4 ratio 1.16 (1.1); shape and setation in juvenile specimens as in juvenile and semiadult males; P-4 without denticles on the ventral surface in adult specimen ( Figs. 71-72).

Remarks. This group includes four Asian species that have a dorsal shield with shoulder platelets fused or partially fused with dorsal plate, characterized with presence of Cxgl-4 posterior to Cxgl-2: Torrenticola occulta Lundblad , T. ussuriensis (Sokolow) , T. microdentifera Cook and T. ungeri (Szalay) . Only one juvenile female specimen of T. occulta has been described from Java ( Lundblad 1971) and according to Wiles (1997), this species cannot be separated from T. ussuriensis (known from Russian Far East). The last species has a shorter P-2 and P-3 ventral projection ( Sokolow 1934), but this character is known to be variable ( Wiles 1997). T. ungeri (Palaearctic) is similar to T. microdentifera Cook ( India) , and the differences between the species ( Cook 1967) is related to the absence of well developed tubercles of P- 4 in T. microdentifera . According to Wiles (1997), this character is known to be variable, and T. microdentifera is probably a synonym of T. ungeri . Understanding the taxonomic position of the species from this group is not possible without additional material from a wide area and/or without the application of molecular genetic techniques.

Our juvenile specimen has ventral denticles and well developed tubercles on P-4 ( Figs. 67, 68, 81-82) and is similar to T. ungeri , but the adult female lacks ventral denticles on P-4 ( Figs. 71-72) and itself is similar to T. ussuriensis . Absence of denticles on ventral surfaces of P-4 (and P-3) is most likely a consequence of growth.

These specimens may represent a species new to science. However, since additional adult specimens are not available, it is not possible to check absence of P-4 ventral denticles in the adult male sex. Hence, the introduction of a new name will create more confusion than information given the present state of knowledge.