Hydraena intraangulata, 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 : 86-87

Hydraena intraangulata new species

(Figs. 140, 142, 250)

Type Material. Holotype (male): Queensland, Leo Creek Mine, McIlwrath Range , E of Coen, ex leaf litter, 13° 32' S, 143° 29' E, 14 August 1984, A. Walford-Huggins. Deposited in the ANIC . Paratypes (19): Queensland, 11 km W by N of Bald Hill, McIlwrath Range, search party campsite, elev. 520 m, 13° 44' S, 143° 20' E, 27 June–12 July 1989, T . A. Weir (1 ANIC); 3 km ENE of Mt. Tozer , 12° 44' S, 143° 14' E, 28 June–4 July 1986, T . Weir & A. Calder (10 ANIC); 3 km ENE of Mt. Tozer , flight intercept trap with trough, rainforest , 12° 44' S, 143° 14' E, 28 June–16 July 1986, T . Weir (1 ANIC); 3 km W of Batavia Downs, Malaise Trap , 12° 40' S, 142° 39' E, 18 June–22 July 1992, P. Zborowski & E. S. Nielsen (2 ANIC); 40 km N Coen , 13° 41' S, 143° 5' E, 25 July 1982, C. Watts (3 SAMA); Hann Tableland, 13 km WNW Mareeba , MDPI intercept trap site No. 31, flight intercept trap, 16° 50' S, 145° 11' E, 17 February 1989 – 20 March 1990, Storey & Dickinson (1 QPIM); Lankelly Ck., McIlwraith Rge., C . York, 13° 45' S, 143° 20' E, 1–30 June 1932, P. J . Darlington (1 MCZ) .

Differential Diagnosis. Similar to H. storeyi in body length, dorsal sculpture, and plaque shape; differing therefrom by the broader body form, the more truncate elytral apices, and the more clearly testaceous color surrounding the pronotal macula (Figs. 141, 142). The aedeagi of the two species also show a relationship, but distinctively differ in many details (Figs. 138, 140).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.43/0.65; head 0.23/ 0.36; pronotum 0.36/0.52, PA 0.40, PB 0.45; elytra 0.85/0.65. Head dark brown, margins of clypeus slightly lighter; pronotum testaceous with large, brown, diffusely margined macula; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker.

Head and pronotum microreticulate, dull. 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. 2xpd those of frons, interstices 1–3xpd; punctures anteriorly and posteriorly only slightly larger than those on disc, interstices ca. 1xpd; PF1 and PF4 absent; PF2 very shallow; PF3 shallow, broad.

Elytral punctures ca. 2–2.5xpd of largest pronotal punctures; punctures becoming smaller and shallower over posterior declivity. Intervals not raised, shining, width about 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly truncate, in posterior aspect margins form strong angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/2/7/4. 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, narrowly triangular depression; plaques weakly raised, straight, tapering and converging anteriorly. AIS flat, width at arcuate posterior margin ca. 2x P2. Profemur with minute sharp tubercle on medial surface near basal 1/3; protibia very weakly arcuate, gradually increasing in width from base to apex; mesotibia slender, straight; metatibia slender, very weakly arcuate and 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. 140) main-piece with strong basal process, mushroom-shaped in ventral view; main-piece greatly angulate near midlength, with two, sharp, thin, blade-like processes together forming V-shape; distal piece with three moderately complicated lobes, and short, arcuate, gonopore-bearing flagellum; left paramere slender, tapering apically, ventral margin with row of about eight setae; right paramere very narrow in proximal 1/2, becoming wider over distal 1/2, setae in two groups, about thirteen setae in row along ventral margin, and about four setae on dorsal margin; large seta, flat and widened apically, on dorsal surface of main-piece. Female last tergite with three incisions, delimiting four lobes, setae slender, tapering.

Etymology. Named in reference to the oval body form and the many angles of the aedeagus.

Distribution. Currently known from northern Queensland (Fig. 250).