Monatractides kyphophorus ( 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 : 5

Monatractides kyphophorus ( K. Viets, 1935)

( Figs. 20–28 )

Material. Thailand: Stream crossing road to Doi Chiang Dao NP, Chiang Dao, 417 m asl, 25.xi.2007, 19° 23.304 N 98° 55.780 E, leg. Smit 0/1/0 (0/1/0 mounted).

Morphology. Female: Idiosoma (ventral view: Fig. 21 ) L 697, W 606; dorsal shield ( Fig. 20 ) L 588, W 463, L/W ratio 1.27; dorsal plate 544; shoulder plate L 194, W 69, L/W ratio 2.8; frontal plate L 126, W 63, L/ W ratio 2.0; shoulder/frontal plate L ratio 1.5; capitular bay L 144; its lateral margin with the three pairs of well developed knob-shaped protrusions ( Fig. 22 ): One pair at the apical tip of Cx-1, two further pairs distally and proximally from the subapical seta; Cx-1 total L 278, Cx-1 medial L 134, Cx-2+3 medial 78; ratio Cx-1 L/Cx-2+3 medial L 3.6; Cx-1 medial L/Cx-2+3 medial L 1.7; the posterior medial region behind the genital field widely rounded; genital field L/W 194/166, L/W ratio 1.17; capitulum ( Fig. 23 ) ventral L 211; chelicera L 248; palp ( Figs. 24–25 ) total L 216, L and %L (given as % of total L): P-1 27 (12.5), P-2 70 (32.4), P-3 41 (19.0), P-4 52 (24.1), P-5 26 (12.0); P-2/P-4 ratio 1.35; L I-Leg-4-6 ( Fig. 28 ): 114, 109, 109.

Remarks. Due to the presence of three pairs of knob-shaped protrusions at the margin of the capitular bay, a rounded capitular bay, an elongated and slender capitular rostrum, and the posterior medial region behind the genital field widely rounded, the specimens from Thaland show a general conformity with descriptions given for Monatractides kyphophorus ( K. Viets, 1935) . The short postgenital area and caudal position of the excretory pore are due to the obviously juvenile age of the specimen (indicated by weak sclerotization).

Jin (1997) reported M. pinapalpis ( Cook, 1967) from China ( Yunan Province) and mentioned a slight difference in the shape of the genital field and the capitulum. Furthermore, he mentioned the presence of three pairs of knob-shaped protrusions at the margin of the capitular bay (not mentioned in the original description of M. pinapalpis by Cook, 1967), so it’s evident that this specimen does not belong to M. pinapalpis . Due to the aforementioned characteristics of M. kyphophorus , it is most probably that the specimens from China belong to M. kyphophorus .

Distribution. Indonesia, probably China? New for Thailand.

Figures

FIGURES 20 – 28. Monatractides kyphophorus (K. Viets), female: 20 = dorsal shield; 21 = idiosoma, ventral view; 22 = capitular buy, with knob-shaped protrusions, lateral view; 23 = capitulum; 24 = palp (P- 1 missing), medial view; 25 = palp (P- 1 missing), lateral view; 26 = anterodorsal portion of ventral shield; 27 = II-Leg- 2 - 6; 28 = I-Leg- 3 - 6. Scale Bars = 100 µm.