Monatractides cameronensis, Pesic, Vladimir & Smit, Harry, 2010

Pesic, Vladimir & Smit, Harry, 2010, New records of water mites (Acari: Hydrachnidia) from Malaysia, with descriptions of three new species, Zootaxa 2354, pp. 19-34 : 26-29

Monatractides cameronensis sp. nov.

( Fig. 7A–K )

Type material. Holotype: male dissected and slide mounted in Hoyer's fluid, Malaysia, stream crossing road to Ringlet, Cameron Highlands, 4° 22.212 N 101° 21.522 E, alt. 1011 m, 18.ii.2009. Paratypes: 1/1/0 (mounted), Jerian stream, Fraser’s Hill, 3° 43.479 N 101° 42.935 E, alt. 1011 m, 14.ii.2009.

Diagnosis. Idiosoma <700 in males, <800 in females (dorsal plate dorsal plate 481–506 in male, 534 in female); dorsal shield with four dorsoglandularia in the area of primary sclerotization of the dorsal plate; P-4 shorter than P-2 (L P-2/P-4 1.2), P-4 with well visible denticle near the insertion of the ventral setae; ejaculatory complex as illustrated in Fig. 7F .

Description. Male (holotype, in parentheses specimen from Jerian stream): Idiosoma (ventral view: Fig. 7C ) L 647 (669), W 472 (481); dorsal shield ( Fig. 7A ) L 528 (547), W 397 (419), L/W ratio 1.33 (1.31); dorsal plate 481 (506); frontal plate L 119 (123), W 58 (53), L/W ratio 2.1 (2.3); shoulder plate L 140 (141), W 59 (61), L/W ratio 2.4 (2.3); shoulder/frontal plate L ratio 1.18 (1.15); gnathosomal bay L 159 (161), Cx-1 total L 248 (266), Cx-1 medial L 88 (105), Cx-2+3 medial 59 (47); ratio Cx-1 L/Cx-2+3 medial L 4.2 (5.7); Cx-1 medial L/Cx-2+3 medial L 1.5 (2.2); genital field L/W 131 (130)/103 (100), L/W ratio 1.27 (1.3), ejaculatory complex as illustrated in Fig. 7F , L 187 (175); distance genital field–excretory pore 142 (156), genital field–caudal idiosoma margin 208 (225); capitulum ( Fig. 7K ) ventral L 146 (151); chelicera L 179 (181); palp ( Figs. 7G–H ) total L 166 (155), dL: P-1, 25 (23); P-2, 48 (45); P-3, 34 (32); P-4, 41 (39); P-5, 18 (16); %L: P-1, 15.1 (14.8); P-2, 28.9 (29.0); P-3, 20.5 (20.6); P-4, 24.7 (25.2); P-5, 10.8 (10.3); L P-2/P-4 ratio, 1.17 (1.15); P-4 with well visible denticle near the insertion of the ventral setae; L I-Leg-4-6 ( Fig. 7E ): 70 (66), 74 (720, 68 (68).

Female (from Jerian stream): Idiosoma (ventral view: Fig. 7D ) L 709, W 513; dorsal shield ( Fig. 7B ) L 588, W 438, L/W ratio 1.34; dorsal plate 534; frontal plate L 134, W 63, L/W ratio 2.1; shoulder plate L 143, W 66, L/W ratio 2.2; shoulder/frontal plate L ratio 1.09; gnathosomal bay L 169, Cx-1 total L 275, Cx-1 medial L 105, Cx-2+3 medial 31; ratio Cx-1 L/Cx-2+3 medial L 8.9; Cx-1 medial L/Cx-2+3 medial L 3.4; genital field L/W 148/131, L/W ratio 1.13; egg maximum diameter L 191; distance genital field–excretory pore 178, genital field–caudal idiosoma margin 253; capitulum ventral L 168; chelicera L 195; palp total L 166, dL and %L (in parentheses): P-1, 25 (15.1); P-2, 48 (28.9); P-3, 34 (20.5); P-4, 41 (24.7); P-5, 18 (10.8); L P-2/P-4 ratio, 1.17; L I-Leg-4-6: 73, 78, 72.

Etymology. The species is named after the Cameron Highlands, where it was collected.

Remarks. This species belongs to the Monatractides macroporus ( K. Viets, 1935) species-complex, characterized by the presence of an anteriorly slender and elongated Cx-1, a relatively short medial suture line of Cx-2+ 3 in both sexes, and a narrower capitular bay ( Pesic & Smit 2009b). For a discussion on the M. macroporus species-complex see Pesic & Smit (2009b). Males of Monatractides cameronensis sp. nov. can be easily distinguished from the known males of other species in this group by the shape of the ejaculatory complex (conventional in shape with well-developed proximal horns in M. macroporus – see: Lundblad 1971, M. macrognathus – see: Lundblad 1971, M. lativentris – see: Pesic & Smit 2009b). Due to the presence of four dorsoglandularia in the area of primary sclerotization of the dorsal plate, M. cameronensis sp. nov. resembles M. major ( K. Viets, 1935) and M. minor Wiles, 1991 . Viets (1935) described M. major as a form of M. macrognathus from Java. Lundblad (1971) considered M. macrognathus and M. macrognathus major , synonymous with M. macroporus , but Wiles (1991) raised M. macrognathus major in ranking to a full species. Wiles (1991) described M. minor based on four female specimens from the Sungai Gombak, Selangor, Malaysia. Monatractides minor differs from M. major in minor idiosoma dimensions and the anterior dorsoglandularia on the dorsal plate lying near the anterior end of the medial muscle scar. Moreover, the anterior margins of the posterior platelets are more swollen ( Wiles 1991) and P-4 is somewhat shorter in M. minor . According to Wiles (1991), it may well be that M. minor is a variety of M. major and that intermediate specimens may be found. Monatractides minor differs in its minor idiosoma and gnathosoma dimensions (e.g., dorsal plate L 306, palp total L 132–146) which lie clearly below the minimum values for both sexes of M. cameronensis sp. nov. (collected about 50 kilometres from the locus typicus of M. minor ). Furthermore, the anterior dorsoglandularia of the dorsal plate in M. cameronensis sp. nov. lie below the anterior end of the medial muscle scar. On the other hand, M. major differs in its major idiosoma and gnathosoma dimensions (e.g., dorsal plate L 710 male, 734 in female, genital field L 182 in male, 196 in female L 132–146, palp total L 234 in male) which are clearly above the maximum values for both sexes of M. cameronensis sp. nov. A further difference is found in the somewhat shorter P- 4 in M. cameronensis sp. nov. Some important characters such as the shape of the ejaculatory complex cannot be discussed because these are lacking in the original description of M. major .

Distribution. Malaysia.

Figures

FIGURE 7 A – K. Monatractides cameronensis sp. nov. (A, C, E – I, K = male; B, D, J = female): A – B = dorsal shield; C – D = ventral shield; E = I-Leg- 5 - 6; F = ejaculatory complex; G = palp, lateral view; H = palp, medial view; E = palp, medial view; I – J = anterodorsal portion of ventral shield; K = capitulum and chelicera. Scale Bars = 100 μm.