Hydraena capetribensis, 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 : 84-85

Hydraena capetribensis new species

(Figs. 136, 139, 260)

Type Material. Holotype (male): Queensland, Cape Tribulation area , flight intercept window/ trough trap, 16° 3' S, 145° 28' E, 21–28 March 1984, A. Calder & T. Weir. Deposited in the ANIC.

Differential Diagnosis. Similar to H. textila in body form and dorsal sculpture (Figs. 135, 136); differing therefrom by the slightly larger size (ca. 1.45 vs. 1.41 mm), the darker color surrounding the pronotal macula, and the oval, more narrowly separated plaques. The aedeagi of the two species also show a relationship, but differ in significant details (Figs. 137, 139).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.45/0.58; head 0.24/ 0.34; pronotum 0.35/0.48, PA 0.40, PB 0.41; elytra 0.82/0.58. Head dark brown except labrum and lateral areas of clypeus light brown to testaceous; pronotum light brown with large, dark brown, diffusely margined macula; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker.

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

Elytral punctures slightly larger than largest pronotal punctures. Intervals not raised, shining, width about 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins form moderate angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/2.5/5/3. P1 laminate; median carina weakly angulate in profile. P2 narrow, l/w ca. 2/1, sides parallel, apex blunt. Plaques located in posterior 1/2 of metaventrite on sides of deep median, narrow subtriangular depression; plaques weakly raised, oval or kidney shaped, more narrowly separated anteriorly than posteriorly. AIS flat, width at arcuate posterior margin slightly greater than 2x P2. Profemur with minute sharp tubercle on medial surface near basal 1/3; protibia weakly arcuate, slightly widened on medial margin near distal 1/3; mesotibia slender, straight; metatibia slender, very weakly arcuate, weakly emarginate on medial margin. Last sternite with small off-center lobe; last tergite with deep, off-center notch, located opposite sternite lobe.

Aedeagus (Fig. 139) main-piece with strong basal process bent toward right side, distal part of main-piece arcuate, in ventral view concealing most of right paramere; distal piece very simple, with long gonopore-bearing flagellum in middle, and short acute process on right side; left paramere slightly angulate on dorsal surface near distal 1/4, then tapering to apex, setae in two groups, a row of about seven setae along ventral margin, and about three setae at apex; right paramere slender, setae in two groups, a row of about seven setae along ventral margin, and about four setae at apex. Females not yet known.

Etymology. Named in reference to the known geographical distribution, Cape Tribulation.

Distribution. Currently known from northeastern Queensland (Fig. 260).