Hydraena pilipes Zwick, 1977

PERKINS, PHILIP D., 2007, A revision of the Australian species of the water beetle genus Hydraena Kugelann (Coleoptera: Hydraenidae), Zootaxa 1489 (1), pp. 1-207 : 109-110

Hydraena pilipes Zwick, 1977

(Figs. 177, 178, 181–183, 245)

Hydraena pilipes Zwick, 1977: 157 .

Type Material. Holotype (male): New South Wales, Sydney [labels: 14623 Sydney // Hydraena pilipes Zwick male Holotypus // DIGITAL IMAGE captured 2004 P. D. Perkins]. Deposited in the SAMA.

Differential Diagnosis. Recognized by the combination of the large body size (ca. 2.15 mm), the very

coarsely and densely punctate pronotum, the coarsely punctate elytra, with some non-serial punctures near the scutellum, and, in males, the very large metatibial brush, with undulating tips. H. pilipes is differentiated from H. queenslandica , the males of which also have large metatibial brushes, by the more densely punctate and differently shaped pronotum (Figs. 178–179). The aedeagi of the two species are very distinct (Figs. 181– 184).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.13/0.88; head 0.28/ 0.44; pronotum 0.51/0.65, PA 0.48, PB 0.63; elytra 1.34/0.88. Dorsum dark brown, head slightly darker, margins of pronotum slightly lighter, legs and palpi light brown, tip of palpus not darker.

Frons punctures ca. 2–3xef; interstices very narrow. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotum densely coarsely punctate, punctures on disc deep, ca. 3xpd those of frons, interstices narrow walls forming reticulate pattern; PF1, PF2 and PF4 absent; PF3 moderately deep.

Elytral punctures about equal size of largest pronotal punctures. Intervals not raised, shining, width ca. 1xpd, as are interstices between punctures of a row. First five or six rows non-serial near base. Apices in dorsal aspect conjointly rounded to subtruncate, in posterior aspect margins forming marked angle with one another.

Plaque/intercoxal process ratios (P2/w/l/s) ca. 1/1/5/1/. P1 laminate; median carina angulate in profile. P2 moderately narrow, l/w ca. 5/4, sides parallel or slightly diverging toward blunt apex. Plaques minute, indistinct ovals at posterior sides of deep median elongate subtriangular depression (plaques virtually absent in some specimens). No midlongitudinal carina between mesoventral intercoxal process and plaques. Cuticle asperite under hydrofuge pubescence. AIS flat, width at arcuate posterior margin 2x P2. Pro- and mesotibia slender. Metatibia with large brush of setae on inner surface of distal 3/4, tips of brush undulating. Abdominal apex markedly asymmetrical.

Aedeagus (Fig. 181–183) main-piece with small lobe on ventral surface, near base, and much larger hooklike process on right side; left paramere very large, with three groups of setae, medioventral part flexible; right paramere much smaller than left, lobe-shaped apically, with setae in two groups; distal piece with large, irregularly shaped process, and smaller, spine-like process. Female last tergite with three incisions, delimiting four lobes, setae slender, tapering.

Distribution. Widely, but very sparsely distributed from eastern central Queensland to Victoria (Fig. 245).

Material Examined (95): New South Wales, 2 km S. Nowra , 34° 52' S, 150° 36' E, 27 November 1998, C. Watts (7 SAMA) ; Beaury Creek, adjacent Woodenbong State Forest, ca. 8 km SW Woodenbong, ca. 120 km SW Brisbane, Residual pools and small rock pools in river bed ( Beaury Creek ), in cultivated cattle country, 28° 24' S, 152° 32' E, 25 August 2004, M. A. Jäch (AU 14) (11 NMW) ; Bruxner Flora Reserve , ex. leaf/ twig debris in streambed pools, 30° 15' S, 153° 6' E, 28 January 1998, P. D. Perkins (4 MCZ) ; Failford , 8 km N, 32° 0' S, 152° 27' E, 18 August 1997, C. Watts (4 SAMA) ; Kiola Forest Pk., 15 km N Batemans Bay, wet sclerophyll litter, elev. 20 m, 35° 42' S, 150° 11' E, 30 August 1982, S. & J. Peck (SBP 119) (14 ANIC) ; O’Sullivan Gap Res. , 11 km NE Buladelah, flight intercept trap, sclerophyll forest (wet), elev. 50 m, 32° 24' S, 152° 13' E, 11 June–27 August 1982, S. & J. Peck (1 ANIC) ; Royal National Park , stream drift, FMHD #83- 265 , 34° 3' S, 151° 3' E, 14 July 1983, L. E. Watrous (1 FMNH) ; Sydney, Griffith Collection [no date], 33° 52' S, 151° 12' E, (1 PZC) ; Queensland, 30 km NE Brisbane, Mt. Nebo Road, Pond, ca. 200 m, Sclerophyll forest , elev. 540 m, 27° 24' S, 152° 48' E, 21 August 2004, M. A. Jäch (AU 1) (6 NMW) ; Eungella N. P., 21° 11' S, 148° 31' E, 1–30 August 1996, J. S. Denton (2 NMW) ; Eungella N. P., Broken River Track , elev. 720 m, 21° 11' S, 148° 31' E, 13 November 1996, L. Hendrich (23) (6 NMW) ; Eungella National Park, end of Dalrymple Road , puddle, 21° 2' S, 148° 34' E, 16 March 1997, P. Zwick (21 PZC) ; Victoria, Simpson Creek , 12 km SW Orbost, 37° 44' S, 148° 20' E, 16 January 1997, C. Watts (16 SAMA) ; Woori Yallock Creek east of Melbourne, on road to Warburton , 37° 44' S, 145° 29' E, 10 November 1972, P. Zwick (1 PZC) .