Hydraena invicta, 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 : 52

Hydraena invicta new species

(Figs. 76, 84, 239)

Type Material. Holotype (male): New South Wales, Sydney, Griffith Collection [no date], 33° 52' S, 151° 12' E. Deposited in the SAMA . Paratypes (6): New South Wales, Same data as holotype (5 SAMA); Royal N. P., Palm Gully, off Lady Wakehurst Drive , subtropical rainforest, wet leaves & flood debris, forest stream, FMHD #86-669 , elev. 80 m, 34° 9' S, 151° 2' E, 25 December 1986, A. Newton & M. Thayer (774) (1 FMNH) .

Differential Diagnosis. Similar to H. cultrata in color pattern (pronotum testaceous) and narrow, carinate plaques; differing therefrom by the slightly larger size (ca. 1.33 vs. 1.25 mm), and the much more coarsely and densely punctate dorsum (Figs. 76, 173). The aedeagi of the two species show some affinity in general shape, but markedly differ in details (Figs. 69, 84).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.33/0.55; head 0.21/ 0.32; pronotum 0.32/0.42, PA 0.35, PB 0.36; elytra 0.78/0.55. Head dark brown, lateral areas of clypeus lighter; pronotum, labrum, maxillary palpi and legs testaceous; elytra brown. Dorsum of head dull, microreticulate.

Frons punctures slightly larger than 1xef; interstices 1–2xpd. Clypeus microreticulate. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotal punctures ca. 2–3xpd largest punctures of frons; interstices very weakly shining, on disc 1–2xpd, anteriorly and posteriorly 0.5–1xpd; PF1 and PF4 absent; PF2 shallow; PF3 shallow, broad.

Elytral punctures slightly smaller than largest pronotal punctures. Intervals not raised, shining, width ca. 2–3xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins form strong angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/5/4. P1 laminate; median carina angulate in profile. P2 moderately narrow, l/w ca. 2/1, sides parallel, apex blunt. Plaques narrow, carinate, slightly convergent anteriorly, located on sides of deep median triangular depression. AIS flat, width at arcuate posterior margin 2x P2. Protibia gradually increasing in width from base to apex, medial margin very weakly emarginate; mesotibia and metatibia slender, simple. Last sternite very slightly asymmetrical, apex weakly produced in small rounded point; last tergite with small, off-center concavity.

Aedeagus (Fig. 84) main-piece with enlargement on ventral surface; distal piece simplified, strongly built, lobate in lateral view, terminating in pointed process above gonopore-bearing process; left paramere widened and with row of sparse setae on ventral margin; right paramere slightly longer than left, arcuate proximally and slightly widened distally, setae in sparse row on distal 1/3 of ventral margin, continuing to apex. Female last tergite with very small apicomedian incision, setae slender, tapering.

Etymology. Named in reference to the strongly built and uncomplicated aedeagus.

Distribution. Currently known from eastern New South Wales (Fig. 239).