Monatractides (Monatractides) neoaustralicus, 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 : 52-55

Monatractides (Monatractides) neoaustralicus sp. nov.

(Figs. 6A–F, 7A–B)

Type series. Holotype, male, 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. Paratypes: one female, same data as holotype, dissected and slide mounted.

Diagnosis. Area of primary sclerotization of the dorsal plate with four dorsoglandularia; capitular bay slender (L/W ratio 3.1–3.3); posterior suture line of Cx-4 well accentuated and directed posterolaterally; excretory pore posterior to the line of primary sclerotization, Vgl-2 posterior to excretory pore; distal margins of P-2 and -3 without denticles, P-4 ventral hairs small, inserted more distally; I-L-6 relatively stout (L/H ratio 2.4). Male: medial suture line of Cx-2+3 short (70 μm); genital field relatively wide (L/W ratio 1.2).

6A–F. Monatractides neoaustralicus sp. nov., male, stream ca. 3 km S of Mokwam: A = dorsal shield; B = ventral shield; C = palp, medial view; D = capitulum; E = I-L-5 and -6; F = ejaculatory complex. Scale bars = 100 μm.

Description. Male (holotype): Idiosoma: (ventral view: Fig. 6B) L 788, W 534; dorsal shield (Fig. 6A) L 659, W 456, L/W ratio 1.45; dorsal plate 613; shoulder plate L 184, W 66–69, L/W ratio 2.7–2.8; frontal plate L 134–138, W 66–69, L/W ratio 2.0–2.2; shoulder/frontal plate L ratio 1.33–1.37; capitular bay L 166, W 53, L/W ratio 3.1; Cx-1 total L 291, Cx-1 medial L 125, Cx-2+3 medial L 70; ratio Cx-1 L/Cx-2+3 medial L 4.2; Cx-1 medial L/Cx-2+3 medial L 1.8; genital field L/W 153/125, L/W ratio 1.22; ejaculatory complex (Fig. 6F) L 178; distance genital field–excretory pore 166, genital field–caudal idiosoma margin 269; capitulum (Fig. 6D) ventral L 186; palp (Fig. 6C) total L 199, dL: P-1, 32; P-2, 54; P-3, 42; P-4, 54; P-5, 17; L P-2/P-4 ratio, 1.0; L I-5-6 (Fig. 6E): 102, 94; I-L-6 L/H ratio, 2.35.

Female: Idiosoma: (ventral view: Fig. 7A ) L 847, W 575; dorsal shield (Fig.) L 706, W 497, L/W ratio 1.42; dorsal plate 656; shoulder plate L 198–200, W 74–77, L/W ratio 2.6–2.7; frontal plate L 134–136, W 69–72, L/W ratio 1.9–2.0; shoulder/frontal plate L ratio 1.47–1.48; capitular bay L 166, W 51, L/W ratio 3.3; Cx-1 total L 296, Cx-1 medial L 130, Cx-2+3 medial L 48; ratio Cx-1 L/Cx-2+3 medial L 6.2; Cx-1 medial L/Cx-2+3 medial L 2.7; genital field L/W 178/165, L/W ratio 1.1; distance genital field–excretory pore 172, genital field–caudal idiosoma margin 309; capitulum ventral L 174; chelicera total L 209; palp ( Fig. 7B ) total L 193, dL: P-1, 32; P-2, 55; P-3, 39; P-4, 51; P-5, 16; L P-2/P-4 ratio, 1.08.

Etymology. Named for its resemblance to Monatractides australicus ( Cook, 1986) .

Discussion. Monatractides neoaustralicus sp. nov. and M. rivulus sp. nov. (see below) belong to the M. macroporus (K. Viets, 1935) species-complex (see: Pešiċ & Smit 2009). Due to the general shape of idiosoma and palp, M. neoaustralicus sp. nov. most closely resembles M. australicus ( Cook, 1986) , a species widespread in Australia ( Pešiċ & Smit 2012). The latter species differs from M. neoaustralicus sp. nov. (and other species of the macroporus -complex from New Guinea) in the excretory pore lying in an indentation of the line of primary sclerotization, while the area of primary sclerotization generally extends more to the posterior margin of the ventral shield, and consequently, Vgl-2 is shifted less away from the excretory pore. Moreover, P-2 and P-3 have more slender, hair-like ventral setae. Two other previously described members of the macroporus -group from New Guinea, Monatractides humilis Pešiċ & Smit 2011 and M. alticolus Pešiċ & Smit, 2011 , can be distinguished in the male by a more elongated genital field (L/W ratio 1.4–1.5 in M. humilis and M. alticolus vs. 1.2 in M. neoaustralicus sp. nov.). Other differences are the well pronounced denticle near the insertion of the ventral hairs in M. humilis and the major idiosoma and gnathosoma dimensions in M. alticolus .

Distribution. New Guinea (West Papua province); only known from the locus typicus ( Fig. 9A ).

Figures

FIGURES 7 A – B. Monatractides neoaustralicus sp. nov., female, stream ca. 3 km S of Mokwam: A = ventral shield; B = palp, lateral view. Scale bars = 100 μm.

FIGURES 9 A – C. A. Stream ca. 3 km S of Mokwam, locus typicus of Monatractides magnus sp. nov. and M. neoaustralicus sp. nov. B. Stream ca. 2.5 km S of Mokwam, locus typicus of M. rivulus sp. nov. C. Stream Ilik near Lake Gita, sampling site of M. magnus sp. nov. Photos. H. Smit.