Hydrobiosella tenuitas sp. nov.

Figures 27–29

Holotype. Male (specimen PT-1038 figured), Queensland, Bellenden Ker Range, summit TV stn, 1560m (about 17°16'S, 145°54'E), 1-7 Nov 1981, Earthwatch-Qld Mus. (NMV, T-21479).

Diagnosis. Males of Hydrobiosella tenuitas can be separated from those of other species in the group by the slender segment X, also slightly dilated apically in lateral view, and the long and slender harpago of the inferior appendages.

Description. Wings similar to H. letti (Fig. 17), length of forewing: male 7.6 mm.

Male. Segment IX in lateral view, length about 1.2 times width, sub-rectangular, not projecting and tapered basally, projecting slightly distally (Fig. 28), with a shallow, wide V-shaped notch medially on distal margin (Fig. 29). Segment X slender, almost parallel sided in basal two-thirds, length about 2.8-2.9 times width, narrowed in apical third (Figs 27, 28), in dorsal view, narrow ‘tongue-shaped, tapered slightly in distal third, narrowly rounded apex (Fig. 27); in lateral view, narrowed at about apical third, dilated slightly distally with bulbous apex (Fig. 28). Phallus generally tube-like; with a pair of slightly curved, slender lateral ‘parameres’ arising from the phallus near middle (Figs 27, 28). Inferior appendages in lateral view, with basal segment sub-trapezoidal, length about 1.4 times maximum width; harpago longer, length about 1.6 times length basal segment, more slender, length about 3.8-3.9 times maximum width, tapered slightly distally, broadly rounded apically (Fig. 28).

Female. Unknown.

Etymology. Tenuitas – Latin for slender (segment X and harpago of inferior appendages).

Remarks. The single male specimen of Hydrobiosella tenuitas was collected from north-eastern Queensland (latitude 17°16'S). Hydrobiosella tenuitas was cited in a checklist (Walker et al., 1995) as Hydrobiosella sp. nov. PT-1038.