Rhynchaustrobates (Victoriabates) bipartitus, Smit, Harry, 2015

Smit, Harry, 2015, The water mite family Hygrobatidae Koch in Australia. The genera Aspidiobatella Cook, Australorivacarus Viets, Gondwanabates Imamura and Rhynchaustrobates Cook (Acari: Hydrachnidia), Zootaxa 4033 (4), pp. 567-583 : 580-581

Rhynchaustrobates (Victoriabates) bipartitus n. sp.

( Figs 11 A–C)

Material examined. Holotype female, Tully River at campground, Tully Gorge NP, Queensland, Australia, 17º 46.280 S 145º 39.073 E, alt. 86 m asl, 4-xi-2014 (QM).

Diagnosis. Dorsum with numerous large and smaller platelets, two of these are much larger than the other platelets (and one bearing the postocularia). Posterior to these large platelets a medial pair. Cxgl-4 close to (indistinct) medial margin.

Description. Female. Idiosoma papillate, dorsally 429 long and 397 wide, ventrally 565 long. Dorsum with numerous rose-coloured platelets, two pairs much larger than other platelets, anterior of these pairs with the postocularia. Posterior to these large platelets, a pair of small platelets with glandularia, and then more posteriorly a pair without glandularia. Roof of camerostome with a short extension. Venter with a large shield incorporating the coxae and the genital field. First coxae fused medially. Suture lines of coxae indistinct, and posterior suture line of fourth coxae obliterated. Cxgl-4 located close to obliterated medial suture line of fourth coxae. Genital field with three pairs of acetabula, gonopore 102 long and 88 wide. Length of P1–P5: 30, 40, 32, 56, 34. Length of I-leg-4–6: 108, 106, 90. Length of IV-leg-4–6: 110, 100, 78. Legs without swimming setae.

Male. Unknown.

Etymology. Named after the divided posteromedial platelet.

Remarks. The new species is very close to R. geometricus Cook, 1986 which has a rounded, undivided posteromedial platelet, although occasionally it is undivided. However. R. geometricus has four pairs of acetabula. Moreover, the chitinized parts of the new species, including the dorsal platelets, are reddish-coloured, while they are yellowish in R. geometricus . The palp of the new species is more slender compared to R. geometricus , especially P3 and P4.

Figures

FIGURE 11. Rhynchaustrobates bipartitus n. sp., holotype female; A. venter; B. dorsum; C. palp. Scale bars = 50 µm.