Monatractides bionus, 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 : 46-48

Monatractides bionus sp. nov.

( Figs. 7 – 9 )

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 a.s.l. Paratypes: 0/1 (mounted), same data as holotype; 1/1, ibid., 15.iii.2010, 3˚ 51.513 S 139˚ 05.570 E, 2007 m a.s.l.

Diagnosis. Idiosoma L> 1000 in males,> 1100 in females; relatively wide capitular bay (L/W ratio 2.1 – 2.3); P-4 with well visible denticle near the insertion of the ventral hairs; Cx-4 strongly extended posterior to the genital flaps; postgenital area large; excretory pore slightly away from the line of primary sclerotization, Vgl-2 posterior and well separated from the excretory pore.

Morphology. Male (holotype, in parentheses some mesaurements of the non-dissected paratype specimen): Idiosoma (ventral view: Fig. 7B ) L 1044 (1135), W 794 (753); dorsal shield ( Fig. 7A ) L 928, W 650, L/W ratio 1.43; dorsal plate L 877; shoulder plate L 254, W 108, L/W ratio 2.35; frontal plate L 194, W 88, L/W ratio 2.2; shoulder/frontal plate L ratio 1.31; capitular bay L 206, W 91, L/W ratio 2.3; Cx-1 total L 341, Cx-1 medial L 134, Cx-2+3 medial 84; ratio Cx-1 L/Cx-2+3 medial L 4.1; Cx-1 medial L/Cx-2+3 medial L 1.6; genital field L/W 208/ 149, L/W ratio 1.4, ejaculatory complex L 197; distance genital field–excretory pore 234, genital field–caudal idiosoma margin 394; capitulum ( Fig. 8C ) ventral L 240; chelicera L 302; palp ( Fig. 8A ) total L 289, L and %L (in parentheses): P-1, 34 (11.8); P-2, 86 (30.0); P-3, 53 (18.3); P-4, 79 (17.3); P-5, 37 (12.8); L P-2/P-4 ratio, 1.09; L I- L-4-6 ( Fig. 8D ): 143, 159, 160.

Female (paratype, in parentheses some mesaurements of the non-dissected paratype specimen): Idiosoma (ventral view: Fig. 9 ) L 1288 (1313), W 913 (875); dorsal shield L 1128, W 777, L/W ratio 1.45; dorsal plate L 1056; shoulder plate L 309, W 134, L/W ratio 2.31; frontal plate L 225, W 116, L/W ratio 1.9; shoulder/frontal plate L ratio 1.37; capitular bay L 247, W 116, L/W ratio 2.1; Cx-1 total L 425, Cx-1 medial L 178, Cx-2+3 medial 58; ratio Cx-1 L/Cx-2+3 medial L 7.3; Cx-1 medial L/Cx-2+3 medial L 3.1; genital field L/W 272/225, L/W ratio 1.2; distance genital field–excretory pore 309, genital field–caudal idiosoma margin 503; capitulum ventral L 288; chelicera total L 361; palp ( Fig. 7B ) total L 346, L and %L (in parentheses): P-1, 40 (11.6); P-2, 104 (30.1); P-3, 64 (18.5); P-4, 95 (27.5); P-5, 43 (12.4); L P-2/P-4 ratio, 1.1; L I-L-4-6: 172, 197, 186.

Etymology. The species is named after the river where it was collected.

Remarks. This species belongs to the M. luteus ( K. Viets, 1935) species-complex (see above). Due the larger dimensions of idiosoma and gnathosoma, and in having broad frontal platelets, Monatractides bionus sp. nov. resembles M. landbergi ( Lundblad, 1941) and M. roseus ( Lundblad, 1941) , both known from Java, Indonesia ( Lundblad 1956, 1971); the latter species has been tentatively reported from Malaysia ( Pešiċ & Smit 2010). Monatractides landbergi differs from the latter species in slightly slender idiosoma, and in having less broad frontal platelets (see Lundblad 1956). Due to these features, M. bionus sp. nov. is more similar to M. landbergi , but can be distinguished from the latter species (in parentheses, data taken from original descriptions, see: Lundblad 1956, 1971) in its larger idiosoma and gnathosoma dimensions (e.g., dorsal shield L/W 670/ 492 in male, L 690 in female; ventral shield L/W 770/ 542 in males, L 800 in female; genital field L/W 167/ 125 in male, 186/ 157 in female; palp total L 218 in male), proportionally wider capitular bay, Cx-4 strongly extended posterior to the genital flaps and Vgl-2 more separated from the excretory pore.

Distribution. New Guinea.

Figures

FIGURE 9. Monatractides bionus sp. nov., female: ventral shield. Scale bar = 100 µm.

FIGURE 7 A – B. Monatractides bionus sp. nov., male: A = dorsal shield; B = ventral shield. Scale bar = 100 µm.

FIGURE 8 A – D. Monatractides bionus sp. nov. (A, C – D = male, B = female): A – B = palp, medial view; C = capitulum; D = I- L- 5 and - 6. Scale bars = 100 µm