Monatractides novaeguineae

Pešić, Vladimir & Smit, Harry, 2011, Water mites of the genus Monatractides Viets (Acari: Hydrachnidia, Torrenticolidae) from New Guinea, with descriptions of nine new species, Zootaxa 2779, pp. 39-62 : 41-43

Monatractides novaeguineae nov. sp.

( Figs. 2 , 4A )

Type series. Holotype, male, dissected and slide mounted; Indonesia, New Guinea, Papua Province: stream near Kampung Kleublouw between Jayapura and Sentani, 28.iii.2010, 2˚ 35.249 S 140˚ 35.187 E, 82 m a.s.l. Paratypes: 1/0 (mounted), River Pos 7, Sentani, 9.iii.2010, 2˚ 33.740 S 140˚ 30.784 E, 103 m a.s.l.; 1/0 (mounted), River Kamp Walker near Uncen, Abepura, 31.iii.2010, 2˚ 34.202 S 140˚ 38.886 E, 144 m a.s.l.

Further records. Indonesia, New Guinea, Papua Province, River Yabawi, upstream of Harapan, 28.iii.2010, 2˚ 34.216S 140˚ 33.723E, 120 m a.s.l. 0/2 (0/1 mounted).

Diagnosis. Idiosoma dimensions small (L/W 700 – 744/ 447 – 494 in males); idiosoma elongated (dorsal shield L/W 1.6 – 1.7); capitular bay rectangular at its proximal end; distal margins of P-3 without denticles, P-4 with well developed tubercles near the insertion of the ventral hairs; Cx-4 with slightly accentuated posterior suture line; postgenital area large; excretory pore close to the line of primary sclerotization, Vgl-2 posterior and well distanced from the excretory pore.

Description. Male (holotype from stream near Kampung Kleublouw, in parentheses paratype from River Pos 7, in square brackets paratype from River Kamp Walker): Idiosoma (ventral view: Fig. 2B ) L 700 (744) [744], W 447 (450) [494]; dorsal shield ( Fig. 2A ) L 597 (631) [650], W 356 (375) [391], L/W ratio 1.68 (1.68) [1.66]; dorsal plate 569 (606) [588]; shoulder plate L 163 (175) [167], W 50 (52) [53], L/W ratio 3.26 (3.37) [3.15]; frontal plate L 108 (117) [113], W 44 (44) [44], L/W ratio 2.46 (2.66) [2.57]; shoulder/frontal plate L ratio 1.5 (1.5) [1.48]; capitular bay L 138 (151) [149], W 66 (67) [78], L/W ratio 2.1 (2.25) [1.9]; Cx-1 total L 234 (250) [253], Cx-1 medial L 95 (99) [103], Cx-2+3 medial 56 (63) [63]; ratio Cx-1 L/Cx-2+3 medial L 4.2 (4.0) [4.0]; Cx-1 medial L/ Cx-2+3 medial L 1.7 (1.6) [1.6]; genital field L/W 135 (137) [136]/106 (106) [113], L/W ratio 1.27 (1.29) [1.2], ejaculatory complex ( Fig. 2D ) L 140 (145); distance genital field–excretory pore 154 (172) [167], genital field– caudal idiosoma margin 269 (283) [300]; capitulum ( Fig. 2C ) ventral L 166 (185) [182]; chelicera L 220 (235) [226]; palp ( Figs. 2E – F ) total L 206 (210) [206], dL: P-1, 25 (25) [26]; P-2, 60 (59) [60]; P-3, 40 (43) [40]; P-4, 50 (52) [52]; P-5, 31 (31) [28]; %L: P-1, 12.1 (11.9) [12.6]; P-2, 29.1 (28.1) [29.1]; P-3, 19.4 (20.5) [19.4]; P-4, 24.3 (24.8) [25.2]; P-5, 15.1 (14.8) [13.6]; L P-2/P-4 ratio, 1.2 (1.14) [1.15]; L I-L-4-6 ( Fig. 2G ): 105 (108) [111], 115 (114) [117], 112 (119) [115].

Additionally we give the measurements for one specimen from River Yabawi which we suspect represents the female sex of Monatractides novaeguineae nov. sp.

Female: Idiosoma (ventral view: Fig. 4A ) L 736, W 464; dorsal shield L 631, W 366, L/W ratio 1.72; dorsal plate L 606; shoulder plate L 164, W 55, L/W ratio 3.0; frontal plate L 106, W 46, L/W ratio 2.3; shoulder/frontal plate L ratio 1.55; capitular bay L 145, W 69, L/W ratio 2.2; Cx-1 total L 231, Cx-1 medial L 87, Cx-2+3 medial 45; ratio Cx-1 L/Cx-2+3 medial L 5.1; Cx-1 medial L/Cx-2+3 medial L 1.9; genital field L/W 147/125, L/W ratio 1.18; distance genital field–excretory pore 181, genital field–caudal idiosoma margin 311; capitulum ventral L 175; chelicera total L 236; palp total L 212, dL and %L (in parentheses): P-1, 24 (11.3); P-2, 62 (29.3); P-3, 42 (19.8); P- 4, 52 (24.5); P-5, 32 (15.1); P-2/P-4 ratio 1.19; palp segments as in male; L I-L-5-6: 118, 114.

Discussion. This species belongs to the M. luteus ( K. Viets, 1935) species-complex, characterized by the presence of anteriorly broad and shorter Cx-1, a relatively wide capitular bay, a relatively short medial suture line of Cx-2+ 3 in both sexes and I-L-6 not greatly expanded ( Pešiċ & Smit 2010).

Due to the considerably elongated idiosoma (e.g., dorsal shield L/W 1.6 – 1.7) and the shape of the capitular bay which is rectangular at its proximal end, Monatractides novaeguineae sp. nov. resembles M. papuensis sp. nov. (see below), but differs in its minor idiosoma and gnathosoma dimensions (e.g., in males: Idiosoma L/W <800/ 500 in M. novaeguineae , L/W> 900/ 600 in M. papuensis , genital field L/W <140/ 120 in M. novaeguineae , L/W> 180/ 130 in M. papuensis , palp total L <215 in M. novaeguineae ,> 250 in M. papuensis ). Further differences are found in a shorter ejaculatory complex in the male with a relatively longer proximal chamber, distal margins of P-3 without denticles and a generally slightly accentuated posterior suture line of Cx-4. In the females, the additional differences are found in the shape of genital field with rounded (in M. papuensis angled) anterolateral margins.

Apart from the diagnostic features, there are ecological differences between these two species: Monatractides novaeguineae sp. nov. was found only in the lowlands, while M. papuensis sp. nov. seems to be restricted to higher elevations.

Etymology. The species is named after the country where it was collected. Distribution. New Guinea.

Figures

FIGURE 2 A – G. Monatractides novaeguineae nov. sp., male: A = dorsal shield; B = ventral shield; C = capitulum; D = ejaculatory complex; E = palp, lateral view; F = palp, medial view; G = I-L- 5 and - 6. Scale bars = 100 µm.

FIGURE 4 A – B. A Monatractides novaeguineae nov. sp., female: ventral shield. B Monatractides papuensis sp. nov., female: ventral shield. Scale bar = 100 µm.