Hydrachna queenslandica, Smit, Harry, 2014

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 : 182

Hydrachna queenslandica n. sp.

( Figs. 10A–D )

Material examined. Holotype male, Lake Emma, Lakefield NP, Queensland, Australia, 15º 17’47.43” S 144º 38’48.05” E, 3-ix-2000 (QM). Paratypes: 0/1/0 (mounted, QM), 4/1/0 ( RMNH), same data as holotype; 1/0/0, Catfish Waterhole, Lakefield NP, Queensland, Australia, 15º 3’57.50” S 144º 17’8.43” E, 4-ix-2000 ( RMNH).

Diagnosis. Idiosoma small (approximately 1180–1700 in male, 1530–1790 in female); dorsal sclerites associated with prae- and postocularia absent or tiny dots; male genital field with a straight anterior margin and posteriorly somewhat truncated.

Description. Male: Idiosoma L/W1467 (1186–1709)/1266 (1025–1528). Sclerites associated with prae- and postocularia absent. Fourth coxae with a short posteromedial extension. Anterior coxae, third and fourth coxae with short secondary sclerotization. First, third and fourth coxae with one seta. Genital field L/W 308/308, anterior margin straight, somewhat truncated posteriorly. Length of PI–PV: 122, 110, 150, 64, 15; PIII relatively stocky, L/ H PIII 2.6 (2.67). Length of I-leg-4–6: 148, 146, 144. Length of IV-leg-4–6: 332, 267, 203. Third and fourth legs with numerous swimming setae.

Female: L/W 1789 (1528)/1588 (1387). Sclerites associated with prae- and postocularia a pair of tiny dots. Fourth coxae with a short posteromedial extension. Anterior coxae, third and fourth coxae with short secondary sclerotization. First, third and fourth coxae with one seta. Genital field 259 wide, anterior margin slightly indented, with one pair of large acetabula. Length of PI–PV 150, 130, 194, 72, 36; L/H of PIII 3.0, less stocky than in male. First legs not measurable. Length of IV-leg-4–6: 348, 356, 227.

Etymology. Named after the state of the type locality.

Remarks. The new species is most close to H. approximata in the stocky palp, but differs in its smaller size, anterior margin of male genital field straight (indented in approximata ) and the different shape of the gonopore (compare fig. 1 of Halík 1940 with fig. 10B). Hydrachna linderi is similar also, but the male genital field is less elongated, and the palp is more slender with the segments much longer.

Figures

FIGURE 10. A – D. Hydrachna queenslandica n. sp., A – C holotype male, D paratype female. A, D = coxal and genital area; B = genital field; C = palp. Scale bars: A, C – D = 200 µm, B = 50 µm.