Hydraena capacis, 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 : 94

Hydraena capacis new species

(Figs. 158, 163, 240)

Type Material. Holotype (male): New South Wales, Unumgar S. F. (nr. Grevillia), Coxs Rd. , elev. 580 m, 28° 27' S, 152° 45' E, subtropical rainforest, flight intercept (window) trap, FMHD #87-177 , berlese, leaf & log litter, forest floor, 6 January 1987, A. Newton & M. Thayer (789). Deposited in the ANIC . Paratypes: Same data as holotype (1 FMNH); Same locality 2–11 January 1987 (1 FMNH) .

Differential Diagnosis. Similar in dorsal sculpture to H. hamifera (Figs. 158, 160); differing therefrom by the larger size (ca. 1.78 mm vs. 1.60 mm), the longer and more convex elytra with more sharply rounded apices, the weakly arcuate and more widely spaced plaques, and, in males, the slightly more arcuate protibiae and the simple metatibiae. The aedeagi of the two species are markedly dissimilar (Figs. 163, 167).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.78/0.71; head 0.27/ 0.38; pronotum 0.40/0.59, PA 0.46, PB 0.49; elytra 1.10/0.71. Head dark brown to piceous; pronotum and elytra dark brown; legs brown; palpi light brown to testaceous, tip of last palpomere not darkened.

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

Elytral serial punctures very regular, about equal size of largest pronotal punctures; intervals not raised, shining, width ca. 1xpd, as are interstices between punctures of a row; apices in dorsal aspect conjointly, narrowly rounded, in posterior aspect margins form very shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/2/9/5. P1 laminate; median carina angulate in profile. P2 narrow, l/w ca. 5/2, sides parallel, apex blunt. Plaques located in posterior 3/5 of metaventrite at margin of median subtriangular depression, plaques very weakly arcuate, weakly convergent anteriorly, each plaque raised and becoming subcarinate at extreme posterior tip. AIS flat, width at arcuate posterior margin 3x P2. Protibia weakly arcuate, slightly thickened in distal 0.5; meso- and metatibia simple. Last sternite with small lobe that fits into emargination of last tergite.

Aedeagus (Fig. 163) wide, main-piece arcuate in lateral view, with a straight, narrow, strongly sclerotized process on the right side; distal piece large compared to main-piece, shield-like, forming a point on the right side; gonopore on slender process near middle of distal piece; left paramere much wider than right, angulate on ventral surface, with a group of setae subapically and another group at angulation; right paramere slender, about same length as left paramere, with setae in two closely approximate groups. Female last tergite with three incisions, delimiting four lobes, setae slender, tapering.

Etymology. "That can hold much"; named in reference to the robust abdomen/elytra and robust aedeagus.

Distribution. Currently known only from the type locality, the Unumgar State Forest, in northeastern New South Wales (Fig. 240).