Monatractides alticolus, Pešić, Vladimir & Smit, Harry, 2011

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 : 55-58

Monatractides alticolus sp. nov.

( Figs. 14 – 16 )

Type series. Holotype, male, dissected and slide mounted; Indonesia, New Guinea, Papua Province: Bion River, upstream, Pass Valley, 15.iii.2010, 3˚ 51.84 S 139˚ 05.733 E, 1962 m asl. Paratypes: 1/1 (0/1 mounted), same data as holotype; 2/2 (1/1 mounted), same data as holotype, 15.iii.2010, 3˚ 51.513 S 139˚ 05.570 E, 2007 m a.s.l..; 3/1, same data as holotype, 02.iii.2010, 3˚ 51.267 S 139˚ 05.789 E, 1962 m a.s.l.

Further records: Indonesia, New Guinea, Papua Province: Wao & Pao streams near confluence Walmak, Nipsan district, 18.iii.2010, 4˚ 07.097 S 139˚ 38.520 E, 1739 m a.s.l. 1/0 (mounted); Yango stream, Walmak, Nipsan district, 19.iii.2010, 4˚ 06.830 S 139˚ 38.587 E, 1757 m a.s.l. 2/2 (1/0 mounted).

Diagnosis. Idiosoma L> 1100 in males,> 1200 in females; area of primary sclerotization of the dorsal plate with four dorsoglandularia; capitular bay narrow (L/W ratio ca. 3.0); distal margins of P-2 and -3 without denticles, P-4 with small denticle near the insertion of the ventral hairs, P-4 ventral hairs inserted more distally, P-4 L/H 2.5 – 2.6; postgenital area large; excretory pore away from the line of primary sclerotization, Vgl-2 posterior and well separated from the excretory pore.

Description. Male (holotype, in parentheses paratype from Bion River, in square brackets specimen from Wao & Pao streams): Idiosoma: (ventral view: Fig. 14B ) L 1163 (1219) [1100], W 806 (900) [744]; dorsal shield ( Fig. 14A ) L 906 (996) [878], W 700 (781) [644], L/W ratio 1.29 (1.28) [1.36]; dorsal plate 860 (934) [825]; shoulder plate L 259 (278) [228], W 97 (109) [97], L/W ratio 2.7 (2.6) [2.4]; frontal plate L 166 (209) [178], W 71 (92) [81], L/W ratio 2.3 (2.3) [2.2]; capitular bay L 258 (256) [238], W 82 (81) [80], L/W ratio 3.15 (3.16) [3.0]; Cx-1 total L 416 (433) [392], Cx-1 medial L 157 (175) [153], Cx-2+3 medial 80 (70) [68]; ratio Cx-1 L/Cx-2+3 medial L 5.2 (6.2) [5.8]; Cx-1 medial L/Cx-2+3 medial L 2.0 (2.5) [2.25]; genital field L/W 238 (261) [219]/169 (184) [159], L/ W ratio 1.4 (1.4) [1.38], ejaculatory complex ( Fig. 15B ) L 266 (292) [225]; distance genital field–excretory pore 216 (259) [206], genital field–caudal idiosoma margin 409 (440) [409]; capitulum ( Fig. 15D ) ventral L 272 (275) [247]; chelicera total L 313 (314) [303]; palp ( Fig. 15A ) total L 292 (316) [294], dL: P-1, 39 (40) [39]; P-2, 87 (92) [85]; P-3, 66 (65) [60]; P-4, 74 (86) [79]; P-5, 26 (33) [31]; %L: P-1, 13.4 (12.7) [13.3]; P-2, 29.8 (29.1) [28.9]; P- 3, 22.6 (20.6) [20.4]; P-4, 25.3 (27.2) [26.9]; P-5, 8.9 (10.4) [10.5]; L P-2/P-4 ratio, 1.18 (1.07) [1.08]; L I-L-4-6 ( Fig. 15C ): 151 (169) [160], 162 (178) [157], 145 (159) [142].

Female (from Bion River, upstream, n = 2): Idiosoma (ventral view: Fig. 16A ) L 1263 – 1356, W 988 – 1000; dorsal shield L 1081 – 1109, W 850 – 856, L/W ratio 1.27 – 1.3; dorsal plate L 1013 – 1044; shoulder plate L 256 – 272, W 109 – 122, L/W ratio 2.1 – 2.5; frontal plate L 203 – 213, W 97 – 100, L/W ratio 2.03 – 2.26; shoulder/frontal plate L ratio 1.24 – 1.26; capitular bay L 266 – 279, W 86 – 91, L/W ratio 3.1; Cx-1 total L 431 – 466, Cx-1 medial L 164 – 184, Cx-2+3 medial 37 – 38; ratio Cx-1 L/Cx-2+3 medial L 11.3 – 12.3; Cx-1 medial L/Cx-2+3 medial L 4.3 – 5.0; genital field L/W 269 – 278/218 – 222, L/W ratio 1.2 – 1.28; distance genital field–excretory pore 248 – 306, genital field–caudal idiosoma margin 497 – 552; capitulum ventral L 291 – 294; chelicera L 328 – 335; palp ( Fig. 16B ) total L 330 – 331, dL and %L (in parentheses): P-1, 43 – 47 (13.0 – 14.2); P-2, 96 (29.0 – 29.1); P-3, 68 – 70 (20.6 – 21.1); P-4, 86 – 89 (26.0 – 27.0); P-5, 32 – 34 (9.7 – 10.3); P-2/P-4 ratio, 1.08 – 1.12; L I-L-4-6: 174 – 175, 182 – 188, 162 – 169.

Discussion. Monatractides alticolus sp. nov. and M. humilis sp. nov. (see below) belong to M. macroporus ( Viets, 1935) species-complex (see Pešiċ & Smit 2009). Due to the less narrow capitular bay (L/W 3.0), larger idiosoma and gnathosoma dimensions and the presence of four dorsoglandularia in the area of primary sclerotization of the dorsal plate, the specimens from New Guinea are close to M. major ( Viets, 1935) , a species described originally from Java as a form of M. macrognathus ( Viets 1935) . 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.

Both species of the M. macroporus ( Viets, 1935) species-complex from New Guinea, M. alticolus sp. nov. and M. humilis sp. nov. (see below) differ from M. major (and the other members of the macroporus -complex from Java, see Viets 1935) in Vgl-2 shifted far away from the excretory pore.

Monatractides australicus ( Cook, 1986) , the Australian member of the M. macroporus species-complex, has a similar less narrow capitular bay, as well as the presence of the four dorsoglandularia in the area of primary sclerotization of the dorsal plate (see: Cook 1986). Both species from New Guinea can be distinguished in having less broad frontal platelets and a proportionally much longer genital field. Monatractides alticolus sp. nov. differs from M. humilis sp. nov. in its major idiosoma and gnathosoma dimensions (e.g., idiosoma L> 1100 in males,> 1200 in females vs. idiosoma L <900 in males, <1000 in females in M. humilis sp. nov.). Further differences are found in a longer ejaculatory complex (compare Figures 15B and 17D ) and P-4 is somewhat more slender (L/H 2.5 – 2.7 vs. 2.2 – 2.3 in M. humilis ) with a slightly less pronounced denticle near insertion of the ventral hairs which are inserted more distally in M. alticolus .

Apart from these diagnostic features, there may be ecological differences between these two species: Monatractides humilis sp. nov. was found only in lowland streams ( Fig. 1C ), while M. alticolus sp. nov. was restricted to higher elevations ( Fig. 1B ).

Etymology. Named for its occurrence at higher elevations.

Distribution. New Guinea.

Figures

FIGURE 14 A – B. Monatractides alticolus sp. nov., male: A = dorsal shield; B = ventral shield. Scale bar = 100 µm.

FIGURE 15 A – D. Monatractides alticolus sp. nov., male: A = palp, lateral view; B = ejaculatory complex, C = I-L- 4 - 6; D = capitulum and chelicera. Scale bars = 100 µm.

FIGURE 16 A – B. Monatractides alticolus sp. nov., female: A = ventral shield; B = palp, lateral view. Scale bars = 100 µm.

FIGURE 17 A – G. Monatractides humilis sp. nov. (A – G = male, H = female): A = dorsal shield; B, H = ventral shield; C = I-L- 5 and - 6; D = ejaculatory complex; E = palp, medial view; F = palp, lateral view; G = capitulum. Scale bars = 100 µm.

FIGURE 1 A – C. A = Map of Papua Province (New Guinea, Indonesia), showing location of 7 sampling sites. Sampling site number abbreviation are as follows: 1 — stream near Kampung Kleublouw, 2 — River Pos 7, 3 — River Yabawi, 4 — River Kamp Walker, 5 — Bion River, 6 — unnamed creek crossing road to Pass Valley, 7 — Wao & Pao streams, 8 — Yango stream. B = River Bion (a high altitude stream); C = Yabawi River (lowland stream). Photos: H. Smit.