Hydraena monteithi, 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 : 41-42

Hydraena monteithi new species

( Figs. 58 , 64 , 255)

Type Material. Holotype (male): Queensland, Thornton Peak , 11 km NE Daintree, elev. 1100 m, 16° 10' S, 145° 22' E, rainforest, sieved litter, Q. M. berlesate no. 606, 1 November 1983, Monteith, Yeates & Thompson. Deposited in the QMBA.

Differential Diagnosis. Similar to H. biimpressa in body size, general coloration, and large, deep pronotal foveae PF2; differing therefrom by the wider pronotum, the more coarsely punctate elytra, and the parallel, posteriorly carinate plaques ( Figs. 58, 60 ). The aedeagi of the two species also show a relationship, differing however in significant details ( Figs. 62, 64 ).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.39/0.61; head 0.24/ 0.34; pronotum 0.33/0.47, PA 0.37, PB 0.37; elytra 0.82/0.61. Dorsum and legs brown, maxillary palpi testaceous, tip not darker.

Frons punctures ca. 1xef; interstices shining, 1–3xpd. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotum cordiform, anterior margin emarginate; punctures on disc ca. 2– 3xpd than those of frons, interstices shining, 1–3xpd, punctures larger and denser anteriorly and posteriorly, interstices sometimes narrow walls forming reticulate pattern; PF1 united to form shallow transverse impression across anteromedian 1/3 of pronotal disc; PF2 well impressed, oval, oblique, separated by about width of a fovea; PF3 deep, broad; PF4 moderately deep.

Elytra very convex, especially over posterior declivity; on basal 1/3 punctures large ca. 1xpd largest pronotal punctures, punctures becoming much smaller over posterior declivity. Intervals not raised, shining, width over basal 1/3 1xpd or less, interstices between punctures of a row slightly larger. Apices in dorsal aspect conjointly, moderately sharply rounded, in posterior aspect margins form shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/1/4/4. P1 narrow, not laminate, median carina very weakly angulate in profile. P2 almost as wide as area separating plaques, short, l/w ca. 3/2, sides parallel, apex blunt. Plaques parallel, narrow, becoming carinate or subcarinate at posterior extreme; plaques located in posterior 7/10 of metaventrite on sides of deep median depression. No midlongitudinal ridge between mesoventral intercoxal process and plaques. AIS large, flat, width at straight posterior margin almost 2x P2. Protibia slender, very weakly arcuate, inner surface with spine-like seta near distal 1/3. Meso- and metatibia slender, straight. Last sternite symmetrical; last tergite with deep apicomedian notch.

Aedeagus ( Fig. 64 ) small and simple; main-piece widened distally in ventral view, widened near midlength in lateral view, with process at distal extreme that continues from right to left, also with very small process at base of left paramere; distal piece short, gonopore-bearing process without flagellum, large hairy lobe on left side, and irregularly shaped membranous lobe on dorsal surface; left and right parameres very short, inserting at same level, about equal in length and each with sparse setae apically. Female last tergite with very small apicomedian incision, setae slender, tapering.

Etymology. Named in honor of the collector, Geoff Monteith.

Distribution. Currently known only from the type locality, Thornton Peak, in northeastern Queensland (Fig. 255).

Remarks. This is a brachypterous, flightless species. The elytra are fused along the suture, and the vestigial wings are about 1/2 as long as the elytra.

Figures

FIGURES 57–60. Hydraena, dorsal and lateral habitus of holotypes. —57. H. hynesi. —58. H. monteithi. —59. H. billi. —60. H. biimpressa.

FIGURES 61–64. Hydraena, aedeagi of holotypes. —61. H. billi. —62. H. biimpressa. —63. H. billi (after Zwick 1977). —64. H. monteithi.