Hydraena blackburni Zaitzev, 1908

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 : 71-72

Hydraena blackburni Zaitzev, 1908

(Figs. 106, 107, 111, 113, 216, 243)

Hydraena evanescens Blackburn, 1898: 229 (primary homonym of Hydraena evanescens Rey, 1884 ).

Hydraena blackburni Zaitzev, 1908: 347 (replacement name for Hydraena evanescens Blackburn ).

Hydraena blackburni Zaitzev ; Zwick, 1977: 172.

Type Material. Holotype (female): Queensland [labels: "Type // 6374 Qu. T. // Blackburn Coll. 1910-236. / / Hydraena evanescens, Blackb. // DIGITAL IMAGE captured 2006 P. D. Perkins "]. Deposited in the BMNH.

Differential Diagnosis. Similar in size, color and dorsal punctation to H. rudallensis ; differing therefrom by the proportionally longer elytra, and the dissimilar plaque ratios (2/1/5/2 vs. 1/1/2.2/1) (Figs. 104–107). The aedeagi of the two species markedly differ (Figs. 108–111, 113).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.36/0.58; head 0.20/ 0.35; pronotum 0.33/0.45, PA 0.38, PB 0.43; elytra 0.84/0.58. Dorsum brown, head and disc of pronotum piceous, legs and palpi light brown to testaceous.

Frons punctures ca. 1xef; interstices effacedly microreticulate, weakly shining, 0.5–3xpd. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum shining, finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotal punctures on disc ca. 1xpd of largest frons punctures, interstices weakly shining, 2–4xpd; punctures denser and slightly deeper anteriorly and posteriorly, interstices effacedly microreticulate; PF1 and PF4 absent; PF2 very shallow; PF3 shallow.

Elytral punctures ca. 1xpd of largest pronotal punctures. Intervals not raised, weakly shining, width about 1xpd, as are interstices between punctures of a row. Each elytron with sublateral depression bordered laterally by rounded ridge. Apices in dorsal aspect conjointly rounded, in posterior aspect margins form shallow angle with one another.

Plaque/intercoxal process ratios (P2/w/l/s) ca. 2/1/5/2. P1 laminate; median carina posterior extreme slightly more elevated than remainder. P2 l/w ca. 7/4, sides parallel, apex blunt. Plaques located in posterior 7/10 of metaventrite on sides of deep median elongate subtriangular depression; plaques widest posteriorly, narrowly separated anteriorly. AIS flat, width at arcuate posterior margin slightly less than 2x P2. Legs simple in both sexes. Last sternite of male symmetrical or nearly so; last tergite with distinctive apicomedian notch.

Aedeagus (Fig. 111, 113) main-piece with distal process on right side, apex rounded; distal piece comparatively simplified, gonopore-bearing flagellum terminal, moderately long; left paramere very narrow, inserting near base, setae sparse, long, apical; right paramere distinctively angulate near midlength (appearing folded in lateral view), with about three long setae just before angulation. Female last tergite with three incisions, delimiting four lobes, setae slender, tapering; gonocoxite as illustrated (Fig. 216).

Distribution. Widely distributed in eastern Queensland and northern Northern Territory (Fig. 243).

Material Examined (159): Northern Territory, 9 km N by E of Mudginbarry , 12° 31' S, 132° 54' E, 10 June 1973, Upton & Feehan (1 ANIC) ; Adelaide River, at Daly River road crossing, 13° 29' S, 131° 6' E, 9 November 1972, E. B. Britton (1 ANIC) ; Cockatoo Lagoon , Keep River Nat. Pk., deep billabong with water lillies and fringing grass, 15° 59' S, 129° 2' E, 23 July 1994, T. Weir & A. Roach (1 ANIC) ; Cooper Creek , 19 km E by S of Mt. Borradaile, 12° 6' S, 133° 4' E, 5 June 1973, M. S. Upton (1 ANIC) ; Jim Jim Creek , 19 km WSW of Mt. Cahill, 12° 58' S, 132° 35' E, 17 July 1973, Upton & Feehan (1 ANIC) ; Katherine Gorge National Park , 14° 19' S, 132° 34' E, 11–12 April 1960, G. H. Hevel & J. A. Fortin (1 USNM) ; Nabarlek Dam , 15 km S by W of Nimbuwah Rock, at light, 12° 12' S, 133° 21' E, 2 June 1973, E. G. Matthews (1 ANIC) ; Noorlangie Creek , 8 km N of Mt. Cahill, at light, 12° 52' S, 132° 47' E, 26 October 1972, E. B. Britton (1 ANIC) ; Stuart Highway, Livingstone Field , 52 km S of Darwin, 12° 44' S, 132° 5' E, 9 November 1972, E. B. Britton (1 ANIC) ; U. D. P. Falls, in billabong, 18–19 July 1980, M. B. Malipatil (1 MAGD) ; Queensland, 1 km W Mingela , 19° 54' S, 146° 42' E, 4 May 1998, C. Watts (1 SAMA) ; 12 km WSW of Paluma, MDPI F. I. T. Site 33, flight intercept trap, 19° 0' S, 146° 4' E, 16 December 1988 – 13 January 1989, Storey & Dickinson (1 QPIM) ; 15 km NE Mareeba, MDPI intercept trap site No. 25, flight intercept trap, elev. 400 m, 16° 56' S, 145° 32' E, 20 December 1985 – 7 January 1986, Storey & Titmarsh (3 QPIM) ; 15 km WNW of South Johnstone , light trap, 17° 35' S, 145° 59' E, 3 January 1986, Fay & Halfpapp (1 QPIM) ; same locality, 17° 35' S, 145° 59' E, 19 November 1986, Fay & Halfpapp (1 QPIM) ; 18 km N Mareeba , intermittent stream, 16° 58' S, 145° 25' E, 20 September 1990, D. Larson (12 MCZ) ; 19 km NE Mareeba, MDPI intercept trap site No. 26, flight intercept trap, 16° 54' S, 145° 34' E, 20 December 1984 – 7 January 1985, Storey & Titmarsh (1 QPIM) ; 20 km N Mareeba , 16° 58' S, 145° 25' E, 20 September 1990, D. & M. Larson (10 MCZ) ; 40 Mile Scrub N. P. via Mt. Garnet, MDPI intercept trap site No. 13, flight intercept trap, 17° 40' S, 145° 7' E, 25 February–4 April 1986, Storey & Heiner (1 QPIM) ; 5 km NNW of Kuranda, MDPI intercept trap, site No. 24, flight intercept trap, 16° 46' S, 145° 36' E, 15 January–20 February 1985, Storey & Halfpapp (4 QPIM) ; 6 km W Dimbulah , 17° 8' S, 145° 6' E, 10 November 1990, D. Larson (6 MCZ) ; Biboohra Storage , 5 km NW Mareeba, 16° 58' S, 145° 25' E, 30 October 1990, D. Larson (20 MCZ) ; Biloela , 24° 24' S, 150° 30' E, 7 September 1972, H. E. Hinton (6 BMNH) ; Burdekin R., 19° 41' S, 147° 36' E, 1 November 1995, C. Watts (1 SAMA) ; Burnett River, Mt. Perry Rd. , 25° 23' S, 151° 46' E, 15 August 2004, A. Glaister (2 NMW) ; Cape River , 100 km S Charters Towers, 21° 0' S, 146° 25' E, 12 December 2002, C. H. S. Watts (3 SAMA) ; Connor’s River , 91.5 miles S Mackay, 22° 39' S, 149° 4' E, 3 September 1972, H. E. Hinton (5 BMNH) ; Gatton , 27° 32' S, 152° 3' E, 9 November 1932, [collector not given] (5 QDPC) ; Girraween N. P., Bald Rock Creek at "Under-ground Creek", ex. sand/gravel streambank, 28° 51' S, 151° 57' E, 22 January 1998, P. D. Perkins (2 MCZ) ; Gladstone [no date], 23° 52' S, 151° 16' E ,, Lea (2 SAMA) ; Greenvale , 150 km NW Charters Towers, elev. 500 m, 19° 0' S, 144° 58' E, 19 January 1993, Wewalka (1 NMW, 5 NMW) ; Hunter's Creek , 5 km NE Mt. Mullay, 18° 7' S, 145° 8' E, 15 November 1990, D. Larson (1 MCZ) ; L. Mitchell R., 40 km N Mareeba, 16° 58' S, 145° 25' E, 21 September 1990, D. Larson (1 MCZ) ; Leichhardt Creek , 8 km N Bluewater, 19° 10' S, 146° 32' E, 18 December 2002, A. J. & C. H. S. Watts (33 SAMA) ; Oxley Creek , 27° 32' S, 153° 0' E, 28 March 1932, H. Hacker (2 QMBA) ; Pentland , 20° 31' S, 145° 24' E, 18 July 1975, J. C. Lesouif (1 ANIC) ; Pioneer R. nr. Mirani , 21° 9' S, 149° 13' E, 4 September 1972, H. E. Hinton (9 BMNH) ; Townsville , light trap, 19° 15' S, 146° 48' E, 31 May–16 June 1968, P. Ferrar (4 ANIC) ; Young’s Crossing, Petrie , 27° 16' S, 152° 57' E, 2 October 1959, I. C. Yeo (1 UQIC, 4 UQIC) .