Hydrachna curtiscutata, 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 : 174

Hydrachna curtiscutata n. sp.

( Figs. 3A–E , 4A–B )

Material examined. Holotype male, Temporary pond along Wyseby road (= road to Carnarvon NP), Queensland, Australia, 24º 59.185 S 148º 24.416 E, alt. 305 m asl, 30-x-2005 (QM). Paratypes: one female (mounted, QM), 3 males, 1 female ( RMNH), same data as holotype.

Diagnosis. Genital field with a large anterior cleft, dorsum with a pair of short sclerites.

Description. Male: Idiosoma approximately 1600 (1930–2070) long. Frontalia associated with postocularia rod-shaped. Posteromedial extension of fourth coxae narrow till nearly absent. Third and fourth coxae posteromedially with well-developed secondary sclerotization of variable width; fourth coxae also with lateral secondary sclerotization. First, third and fourth coxae with one seta. Genital field 429 long and 421 wide, with numerous acetabula and a large anterior cleft. Shape of gonopore as in fig. 3E. Length of PI–PV: 117, 178, 219, 98, 50; PIII rather stocky, L/H PIII 2.6.

Female: Idiosoma L/W 3115 (2512)/ 2714. Frontalia associated with postocularia rod-shaped, one of these geniculated. Preocularia on a short sclerite or absent. Third and fourth coxae medially with well-developed secondary sclerotization; fourth coxae also with lateral secondary sclerotization. First, third and fourth coxae with one seta. Genital field 397 long, deeply indented anteriorly, with numerous acetabula, one pair enlarged. Lengths of PI–PV: 203, 243, 324, 122, 68; L/H PIII 2.5; palp as in male. Length of IV-leg-4–6: 543, 502, 348.

Etymology. Named for the short dorsal sclerites.

Remarks. The new species is close to H. multipora Cook, 1967 from India and H. tenuissima K. Viets, 1935 from Sumatra in the shape of the genital field, the latter only know in the female sex. The new species differs from both species in the presence of short elongated dorsal sclerites. Hydrachna multipora has a stockier palp, while PI is much higher. The female of H. tenuissima has long the fourth coxae with a long and narrow posteromedial extension.

Figures

FIGURE 3. A – E. Hydrachna curtiscutata n. sp., A – D holotype male, E paratype male. A = dorsal view; B = coxal and genital area; C = genital field; D = palp and capitulum; Scale bars: A – B, D – E = 200 µm, C = 50 µm.

FIGURE 4. A – B. Hydrachna curtiscutata, n. sp., paratype female. A = dorsal view; B = genital field. Scale bars: A – B = 200 µm.