Barwontius

Smit, Harry, 2007, New Records of Hyporheic Water Mites from Australia, with a Description of Two New Genera and Ten New Species (Acari: Hydrachnidia), Records of the Australian Museum 59 (2), pp. 97-116 : 107

Barwontius setipes n.sp.

Figs. 25–30

Type material. HOLOTYPE: male, Carters Creek at crossing with Western Distributor Road, New South Wales, Australia, 35°30.914'S 150°03.546'E, alt. 187 m, 16 December 2003 ( AMS).

Diagnosis. I-leg-5 with a large, curved seta, I-leg-4 with two large, straight setae. Ventral margin of PII with large denticles.

Description. Male: Dorsal and ventral shields present, dorsal furrow complete. Idiosoma ventrally 567 long and 397 wide, dorsally 486 long. Dorsum with three paired plates and a large posteromedial plate. Anteromedial plates with postocularia, anterolateral plates with two pairs of glandularia, posterolateral plates with one pair of glandularia. Large posteromedial plate with three pairs of glandularia. None of the associated seta of the dorsal glandularia enlarged. One pair of eyes present. Dorsal shield 470 long and 373 wide, posteromedial plate 324 long and 243 wide. First coxal plates extending beyond anterior idiosoma margin. Tips of first coxal plates gradually tapering. Glandularia of fourth coxal plates located near posterior margin of fourth

coxal plates. Fourth coxal plates with a slight development of parallel ridges, mainly near lateral margin. Two pairs of glandularia located lateral of genital field. Genital field with relatively few acetabula, approximately 12, but exact number difficult to ascertain. Lengths of PI–PV: 34, 82, 42, 106, 48; PIV with large flap-like extensions, extending well beyond anterior margin of segment. Ventral margin of PII with 5–6 denticles. Lengths of I-leg-4–6: 110, 108, 74. I-leg-5 with a large, curved heavy seta, I-leg-4 with two large, straight heavy setae; 1–2 smaller setae present as well on these leg segments. Lengths of IV-leg-4–6: 134, 132, 126. IV-leg-5 with four ventral seta, the posterior seta enlarged; IV-leg-6 with one ventral seta. Legs without swimming setae. Claws of legs with clawlet and small claw blade.

Female: Unknown.

Etymology. Named for the peculiar stout setae of the first leg.

Remarks. No other Australian Barwontius species has the first leg modified as in the new species. Moreover, in most other species PII is smooth or with very small denticles.

Figures

Figs 25–30.Barwontius setipes n.sp., holotype male, (25) ventral view; (26) dorsal view; (27) palp; (28) palp; (29) I-leg-4–6; (30) IV-leg-4–6. Scale bars = 50 µm.