Hydraena dorrigoensis, Published, 2007

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 : 36

Hydraena dorrigoensis new species

( Figs. 46 , 50 , 262)

Type Material. Holotype (male): New South Wales, Dorrigo National Park, Rosewood Creek, upstream from Coachwood Falls , elev. 650 m, ex. gravel/sand stream bank, 30° 22' S, 152° 40' E, 26 January 1998, P. D. Perkins. Deposited in the QMBA.

Differential Diagnosis. Similar to H. spinissima in size, dorsal punctation, and general color pattern ( Figs. 45, 46 ); differing therefrom in a greater contrast between the dark brown pronotal macula and the surrounding testaceous area, the more elongate plaques, and the deeper metaventral depression. The aedeagi of the two species are markedly dissimilar ( Figs. 50, 52 ).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.63/0.64; head 0.28/ 0.31; pronotum 0.39/0.48, PA 0.41, PB 0.42; elytra 0.94/0.64. Head dark brown to piceous; pronotum with dark brown transverse macula surrounded by testaceous; elytra dark brown; legs and palpi testaceous, tip of last palpomere not darker.

Frons punctures ca. 1xef; interstices shining on disc, 1–2xpd, microreticulate laterally. Clypeus microreticulate. Mentum and postmentum weakly shining, very finely sparsely punctate. Genae weakly raised, lacking posterior ridge. Pronotal punctures on disc ca. 1–2xpd those of frons, interstices shining, 1–2xpd, punctures slightly denser anteriorly and posteriorly; PF1 and PF4 absent; PF2 shallow; PF3 moderately deep, broad.

Elytral punctures basally ca. 1xpd of largest pronotal punctures, becoming much smaller over posterior declivity. Intervals not raised, shining, width basally ca. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins form shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1.5/1/7/3. P1 laminate; median carina weakly angulate in profile. P2 l/w ca. 2/1, sides converging, apex blunt. Plaques very small and widely separated, located at posterior sides of large, very deep, subtriangular median depression. AIS flat, width at arcuate posterior margin ca. 3x P2. Protibia (male) gradually increasing in width from base to just past midlength, then medial margin deeply excavate, a strong spine as base of excavation; mesotibia and metatibia slender, straight. Last tergite with apicomedian notch.

Aedeagus ( Fig. 50 ) main-piece with large basal oriface, apically with several sharply pointed processes; distal piece with large, hood-like process that extends over other processes; gonopore-bearing flagellum short; parameres slender, inserting at same level on main-piece, left much longer than right, setae sparse, terminal or nearly so. Females not yet known.

Etymology. Named in reference to the geographical distribution.

Distribution. Currently known only from the type locality in Dorrigo National Park, New South Wales (Fig. 262).

Figures

FIGURES 45–48. Hydraena, aedeagi of holotypes. —45. H. spinissima. —46. H. dorrigoensis. —47. H. antaria. —48. H. luminicollis.

FIGURES 49–52. Hydraena, aedeagi of holotypes. —49. H. tricantha. —50. H. dorrigoensis. —51. H. tricantha (after Zwick 1977). —52. H. spinissima.