Monatractides parviventris ( K. Viets, 1935 )

Pesic, Vladimir & Smit, Harry, 2009, Water mites of the family Torrenticolidae (Acari: Hydrachnidia) from Thailand, Part II. The genus Monatractides K. Viets, Zootaxa 2012, pp. 1-27 : 8-10

Monatractides parviventris ( K. Viets, 1935)

( Figs. 29–40 )

syn. Torrenticola pusta Cook 1956 – Lundblad 1969: 333.

Material. Thailand: Pong Creek crossing road to Muang Kong, Doi Chiang Dao, 477 m asl, 22.xi.2007, 19° 24.774 N 98° 55.127 E, leg. Smit 0/2/0; stream near Haewsai Waterfall, Nam Nao NP, 425 m asl, 16.xi.2007, 16° 40.668 N 101° 41.856 E, leg Smit (1/5/0) (1/1/0 mounted); stream crossing road to Phu Goom Khao, Nam Nao NP, 803 m asl, 16.xi.2007, 16° 38.410 N 101° 34.886 E, leg Smit 10/8/0 (1/0/0 mounted).

Morphology. Male (Haewsai Waterfall, in parentheses specimen from stream crossing road to Phu Goom Khao): Idiosoma (ventral view: Fig. 30 ) L 631 (553), W 575 (475); dorsal shield ( Fig. 29 ) L 569 (481), W 456 (384), L/W ratio 1.25 (1.25); dorsal plate L 531 (456); shoulder plate L 136 (103–106), W 59 (47–50), L/W ratio 2.3 (2.12–2.19); frontal plate L 141 (125–127), W 56 (48–50), L/W ratio 2.5 (2.6–2.7); shoulder/frontal plate L ratio 0.96 (0.81–0.85); capitular bay L 141 (113), W 50 (41), L/W ratio 2.8 (2.8); Cx-1 total L 247 (203), Cx-1 medial L 106 (91), Cx-2+3 medial 39 (39); ratio Cx-1 L/Cx-2+3 medial L 6.3 (5.2); Cx-1 medial L/Cx-2+3 medial L 2.7 (2.3); genital field L/W 134 (119)/106 (94), L/W ratio 1.3 (1.3), ejaculatory complex ( Fig. 35 ) L 188 (152); distance genital field–excretory pore 125 (100), genital field–caudal idiosoma margin 203 (194); capitulum ( Fig. 32 ) ventral L 131 (126); chelicera L 206 (171); palp ( Figs. 33–34 ) total L 197 (154), L: P-1 27 (19), P-2 56 (46), P-3 38 (30), P-4 55 (43), P-5 21 (16); %L (given as % of total L): P-1 13.7 (12.3), P-2 28.4 (29.9), P-3 19.3 (19.5), P-4 27.9 (27.9), P-5 10.7 (10.4); P-2/P-4 ratio 1.02 (1.07); L I-Leg-4- 5 ( Fig. 36 ): 94 (71), 102 (80), 94 (87).

Female (Haewsai Waterfall): Idiosoma (ventral view: Fig. 38 ) L 713, W 625; dorsal shield ( Fig. 37 ) L 641, W 518, L/W ratio 1.2; dorsal plate L 606; shoulder plate L 141, W 63, L/W ratio 2.2; frontal plate L 150, W 55, L/W ratio 2.7; shoulder/frontal plate L ratio 0.94; capitular bay L 147, W 48, L/W ratio 3.1; Cx-1 total L 253, Cx-1 medial L 106, Cx-2+3 medial 22; ratio Cx-1 L/Cx-2+3 medial L 11.5; Cx-1 medial L/Cx-2+3 medial L 4.8; genital field L/W 159/141, L/W ratio 1.1; distance genital field–excretory pore 148, genital field–caudal idiosoma margin 253; capitulum ventral L 168; chelicera L 218; palp ( Fig. 39 ) total L 203, L and %L (given as % of total L): P-1 28 (13.8), P-2 58 (28.6), P-3 38 (18.7), P-4 57 (28.1), P-5 22 (10.8); P-2/P-4 ratio 1.02; L I-Leg-4-5: 97, 102, 105

Remarks. The specimens from Thailand agree with M. parviventris ( K. Viets, 1935) due to its large frontal plates (L/W ratio 2.5–2.7), which are longer than the shoulder plates (shoulder/frontal plate L ratio 0.94–0.96), the medial suture line of Cx-2+3 is short in both sexes (ratio Cx-1 medial L/Cx-2+3 medial L 2.7 in male, 4.8 in female), P-4 with well visible denticle near the insertion of the ventral hairs and Cx-4 posteriorly extending far beyond the genital field.

Distribution. Indonesia, Sulawesi, Brunei, India (” Torrenticola pusta ” Cook 1967 ), Sri Lanka (” Torrenticola pusta ” K.O. Viets 1973 ). New for Thailand.

Figures

FIGURES 29 – 36. Monatractides parviventris (K. Viets), male, Haewsai Waterfall: 29 = dorsal shield; 30 = idiosoma, ventral view; 31 = anterodorsal portion of ventral shield; 32 = capitulum; 33 = palp, lateral view; 34 = palp, medial view; 35 = ejaculatory complex; 36 = I-Leg- 5 - 6. Scale Bars = 100 µm.

FIGURES 37 – 40. Monatractides parviventris (K. Viets), female, Haewsai Waterfall: 37 = dorsal shield; 38 = idiosoma, ventral view; 39 = palp, lateral view; 40 = anterodorsal portion of ventral shield. Scale Bars = 100 µm.