Monatractides (Monatractides) magnus, Pešić, Vladimir & Smit, Harry, 2012

Pešić, Vladimir & Smit, Harry, 2012, Second contribution to the knowledge of water mites of the genus Monatractides K. Viets (Acari: Hydrachnidia, Torrenticolidae) from New Guinea, with descriptions of three new species, Zootaxa 3350, pp. 46-57 : 50-52

Monatractides (Monatractides) magnus sp. nov.

( Figs. 4A–B , 5A–D)

Type series. Holotype female, dissected and slide mounted, Indonesia, New Guinea, West Papua province: stream ca. 3 km S of Mokwam, 08.xi.2011, 1˚ 05.877 S, 133˚ 54.223 E, alt. 1637 m asl. Paratype: one female, dissected and slide mounted, stream Ilik near Lake Gita, Anggi Lakes, 17.xi.2011, 1˚ 21.423 S, 133˚ 58.553 E, alt. 1912 m asl.

Diagnosis (Male unknown). Idiosoma large (L> 1000) and elongated (dorsal shield L/W 1.7); ventral margin of P-2 and -3 with a straight, stout seta, ventral seta on P-2 more slender and relatively longer, P-4 with well developed denticles near the insertion of the ventral hairs; excretory pore incorporated into primary sclerotization of the ventral shield.

Description. Female (holotype, in parentheses paratype from stream Ilik): Idiosoma: (ventral view: Fig. 4B ) L 1026 (1000), W 675 (688); dorsal shield ( Fig. 4A ) L 894 (875), W 548 (538), L/W ratio 1.63 (1.63); dorsal plate 833 (815); shoulder plate L 272–273 (272), W 91–92 (91), L/W ratio 3.0 (3.0); frontal plate L 167–169 (153–159), W 78–79 (80–84), L/W ratio 2.1 (1.9); shoulder/frontal plate L ratio 1.6 (1.7–1.8); capitular bay L 225 (209), W 97, L/W ratio 2.3; Cx-1 total L 391 (359), Cx-1 medial L 166 (149), Cx-2+3 medial L 25 (33); ratio Cx-1 L/Cx-2+3 medial L 15.6 (10.9); Cx-1 medial L/Cx-2+3 medial L 6.6 (4.5); genital field L/W 219 (219)/206 (200), L/W ratio 1.06 (1.1); distance genital field–excretory pore 206 (212), genital field–caudal idiosoma margin 378 (375); capitulum (Fig. 5D) ventral L 247 (234); chelicera total L 322 (322); palp (Figs. 5A–B) total L 291 (294), dL: P-1, 37 (37); P-2, 80 (86); P-3, 62 (62); P-4, 79 (79); P-5, 33 (30); L P-2/P-4 ratio, 1.01 (1.09); L I-4–6 (Fig. 5C): 120 (119), 147 (153), 152 (151); I-L-6 L/H ratio, 3.0 (3.0).

Male. Unknown.

Etymology. Named for its large size.

Discussion. Due to the similar shape of palp (straight stout seta on the ventral margin of P-2 and P-3) and the excretory pore incorporated into primary sclerotization of the ventral shield, Monatractides magnus sp. nov. is rather close to M. sentanicus Pešiċ & Smit, 2011 (see above). It can be distinguished from the latter species in its larger idiosoma and gnathosoma dimensions (e.g. idiosoma L> 1000, genital field L> 200, palp total L> 270 vs. idiosoma L <700, genital field L <150, palp total L <220 in M. sentanicus ) and a more slender and relatively longer, straight stout seta on the ventral margin of P-2 (compare Figs. 3C and 5A–B).

Distribution. New Guinea (West Papua province).

– D. magnus sp. nov., (A – paratype, stream near B–D – stream ca. 3 km S of Mokwam): A = palp, lateral view; B = palp, medial view; C = I-L-4–6; D = capitulum and chelicera. Scale bars = 100 μm.

Figures

FIGURES 4 A – B. Monatractides magnus sp. nov., female, stream ca. 3 km of Mokwam: A = dorsal shield; B = ventral shield. Scale bar = 100 μm.

FIGURES 3 A – C. Monatractides sentanicus Pešić & Smit 2011, female, unnamed creek N of Sentani: A = dorsal shield; B = ventral shield; C = palp, medial view. Scale bars = 100 μm.