Hydrachna tasmanica Lundblad, 1947

Smit, Harry, 2014, Australian water mites of the genus Hydrachna Müller, with the description of five new species (Acari: Hydrachnidia: Hydrachnidae), Zootaxa 3827 (2), pp. 170-186 : 183-184

Hydrachna tasmanica Lundblad, 1947

( Fig. 11A–B )

Material examined. Tasmania. 1/1/0, Big Waterhouse Lake, Waterhouse Protected Area, 21-x-1997; 1/1/1, Blackmans Lagoon, Waterhouse Protected Area, 21-x-1997. New South Wales. 0/1/0, White Rock River at crossing with Imlay Road, South East Forests NP, 37º 0 8.121 S 149º 21.370 E, alt. 505 m asl, 10-xii-2003.

Description. Male: Idiosoma L/W 2462–1990/2211–1869 (young male). Dorsum as described by Lundblad (1947) for the female: two pairs of minute platelets, the anterior platelets rounded, the posterior platelets more elongated. Fourth coxal plates not extending posteromedially, with short secondary sclerotization. Fourth coxae with one pair of setae, first coxae with two short setae in posteromedial corner. L/W genital field 437/397. Genital field slightly lobate, with one pair of larger acetabula; numerous setae in posterior half of genital field. Length of PI–PV: 219, 209, 324, 100, 50; PIV slender, L/H 4.15. Chelicera 470 long. Length of I-leg-4–6: 211, 227, 267 (till tip of segment). Length of IV-leg-4–6: 571, 535, 300. Female: one specimen measured: L/W 2814/2633.

Remarks. The male has not been described before. The species is characterized by a long PIV and fourth coxae without posteromedial extension. The female from New South Wales is in most aspects (palp slender, fourth coxae medially rounded) similar to the female from Tasmania. This female is 2271 long, PIII is 348 long and L/W of the genital field is 340/502, and therefore in all measurements smaller than the females from Tasmania. Previously known only from Tasmania.

Figures

FIGURE 11. A – B. Hydrachna tasmanica Lundblad, male. A = coxal and genital area; B = palp and rostrum. Scale bar = 200 µm.