Arrenurus (Micruracarus) contortus, Pešic & Smit, 2016

Pešic, V. & Smit, H., 2016, New records of water mites from Southeast Asia (Acari: Hydrachnidia) with the description of two new genera and 12 new species, Acarologia 56 (3), pp. 393-433 : 432

Arrenurus (Micruracarus) contortus n. sp.

( Figure 24 )

Type series — Holotype male, dissected and slide mounted, Vietnam, 15-44-1 Bach MAE National Park, brook with a pool behind a natural barrier, 16°11’15.5"N, 105°50’54.7"E, alt. 1130 m a.s.l., water depth 0.2 m, substrate: leaves in a lentic bay, 2.v.2015.

Diagnosis — Petiole consisting of hyaline appendages; posterior dorsal margin with a pair of double-lobed hyaline membranes; genital plates reversed wing-shaped, broadening laterally; gonopore very narrow.

Description — Male: Idiosoma lilac, dorsally 603 long and 543 wide. Dorsal shield complete, 381 wide. Dgl-3, Dgl-4 and Lgl-4 (conform Wiles 1997) not well visible in dorsal view due to bowing of the dorsal shield. Pygal lobes absent. Posterior dorsal margin with a pair of two-lobed hyaline membranes. Posterior margin ending in a blunt, rounded projection, flanked by a pair of knob-like extensions. Cx-I extending beyond anterior idiosoma margin. Distance of tip of Cx-I to posterior idiosoma margin 640 µm. Genital plates reversed wing-shaped, broadening laterally, slightly extending onto lateral idiosoma margin. Gonopore very narrow, 60 µm long. Idiosoma posteromedially with a concavity, with the petiole in it. Petiole consisting of two hyaline appendages, their shape dependent on position of the specimen. Besides the hyaline petiole a double-tipped hyaline appendage present. Palp: total L 214, dL: P-1, 28; P-2, 52; P-3, 42; P-4, 54; P-5, 38; P-2 medially with four setae, dorsally with three setae; P-3 with a long medial seta. Legs: dL of I-L-4-6: 86, 86, 76; dL of IV-L-4-6: 122, 112, 92; IV-L-4 without a spur. Third and fourth legs with numerous swimming setae. Female: Unknown.

Etymology — Named for the complicated structure of the appendages.

Remarks — The shape of the genital plates is very unusual, and thus far found in the subgenus Rhinophoracarus Viets, 1916 and in a small number of other subgenera. However, members of Rhinophoracarus have a very long petiole, very unlike the hyaline petiole of the new species. Due to the presence of a hyaline petiole and hyaline appendages assignment to Micruracarus seems most appropriate.

Distribution — Vietnam; only known from the locus typicus ( Figure 25C ).

Figures

FIGURE 24: Arrenurus contortus n. sp., male, Bach MAE National Park, Vietnam: A – dorsal view; B – ventral view; C – detail of posterior idiosoma margin; D – right palp; E – left palp. Scale bars: A-B – 200 µm, D-E – 50 µm.

FIGURE 25: Photoghraphs of sampling sites: A – Laos, Kauangxi Waterfall (locus typicus of Monatractides laosensis n. sp., Hexaxonopsis laosensis n. sp., Sinaxonopsis laosensis n. sp. and Africasia purpurea n. sp.); B – Laos, Kouangxi Waterfall, pond behind artifical barrier (sampling site of Hygrobates hamatus K. Viets, 1935, H. henni Wiles, 2004 and locus typicus of Forelia gereckei n. sp.); C – Vietnam, Bach MAE National Park, brook with a pool (sampling site of Monatarctides sp. and locus typicus of Limnesia scharfi n. sp., Schwoerbelia pioniformis n. sp. and Arrenurus contortus n. sp.; D – Cambodia, moat around the main Angkor temple (locus typicus of Hexaxonopsis