Hydraena magnetica Zwick, 1977

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 : 16-17

Hydraena magnetica Zwick, 1977

( Figs. 11 , 15 , 210, 248)

Hydraena magnetica Zwick, 1977: 180 .

Type Material. Holotype (male): Queensland, Magnetic Island [ca. 19° 8' S, 146° 50' E] [labels: Magnetic I. N. Queensland A. M. Lea // Hydraena magnetica Zwick male Holotypus // DIGITAL IMAGE captured 2004 P. D. Perkins]. Deposited in the SAMA.

Differential Diagnosis. Similar in size, body form and plaques to H. miniretia ; differing therefrom by the non-microreticulate pronotal interstices and the more finely punctate elytral series ( Figs. 11, 12 ). The aedeagi of the two species differ distinctively ( Figs. 15, 16 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.13/0.44; head 0.17/ 0.29; pronotum 0.29/0.37, PA 0.32, PB 0.33; elytra 0.67/0.44. Head and large pronotal macula piceous, margins of pronotum light to dark brown, elytra dark brown, legs and maxillary palpi light brown to testaceous.

Frons punctures slightly smaller than 1xef; interstices shining, 2–5xpd. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotal punctures on disc slightly larger than those of frons, interstices shining, 2–3xpd, punctures denser at anterior, interstices ca. 1–2xpd; PF1 and PF4 absent; PF2 very small and shallow, nearly absent; PF3 shallow.

Elytral punctures about equal size of largest pronotal punctures. Intervals not raised, shining, width about 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect gradually rounded to subtruncate, in posterior aspect margins form moderately strong angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/3/4. P1 laminate; median carina angulate in profile. P2 narrow, l/w ca. 2/1, sides parallel, apex blunt. Plaques narrow, elongate ovals, widely separated and nearly parallel to one another, located in posterior 1/3 of metaventrite on sides of shallow median depression. AIS flat, width at arcuate posterior margin 2–3x P2. Protibia slightly widened near midlength; metatibia with small indistinct setae on medial surface of distal 0.5. Last sternite and last tergite simple, symmetrical.

Aedeagus ( Fig. 15 ) main-piece much wider distally than at base, with small, hook-like process on apical part of right side; distal piece (ventral view) with two lobes and two curving flagella; parameres simple, left slightly longer than right. Female last tergite with small apicomedian incision, setae slender, tapering; gonocoxite as illustrated (Fig. 210).

Distribution. Currently known from several localities in northern Queensland, three localities in southern Queensland, and two localities in Victoria (Fig. 248).

Material Examined (137): Queensland, 15 km NE Mareeba, MDPI intercept trap site No. 25, flight intercept trap, elev. 400 m, 16° 56' S, 145° 32' E, 7 January–12 February 1985, Storey & Halfpapp (1 QPIM) ; same locality, elev. 400 m, 16° 56' S, 145° 32' E, 20 March–1 May 1985, Storey & Titmarsh (2 QPIM) ; 30 km NE Brisbane, Mt. Nebo Road, Pond, ca. 200 m, Sclerophyll forest , elev. 540 m, 27° 24' S, 152° 48' E, 21 August 2004, M. A. Jäch (AU 1) (3 NMW) ; 40 Mile Scrub N. P. via Mt. Garnet, MDPI intercept trap site No. 13, flight intercept trap, 17° 40' S, 145° 7' E, 21 December 1985 – 10 January 1986, Storey & Heiner (2 QPIM) ; Boggy Ck., 75 km Cooktown, Cooktown Rd. , 16° 37' S, 145° 21' E, 26 April 1976, E. B. Britton (7 ANIC) ; Broken River , 50 miles W of Mackay, 19° 32' S, 144° 54' E, 30 November 1968, S. Misko (5 ANIC) ; Burnett River, Mt. Perry Rd. , 25° 23' S, 151° 46' E, 15 August 2004, A. Glaister (1 NMW) ; Danbulla St. For., via Atherton , 17° 10' S, 145° 39' E, 14 June 1978, D. Gibson (1 ANIC) ; Emu Creek, 20 km S. Mareeba , 16° 58' S, 145° 25' E, 20 October 1990, D. Larson (10 MCZ) ; 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 (64 MCZ) ; Mulgrave River, The Fisheries , 17° 11' S, 145° 44' E, 9 November 1990, D. Larson (1 MCZ) ; Palmerston N. P., Learmouth Creek , ca. 14 km SE Millaa Millaa, on loop road, ex. bare rocks in splash zone, 17° 34' S, 145° 42' E, 16 January 1998, P. D. Perkins (7 MCZ) ; Parmentier Crk. , 7 miles SW Kuranda, 16° 49' S, 145° 38' E, 21 March 1969, J. Balfour-Browne (11 BMNH) ; Reedy St., George R. Cooktown Rd. , 16° 28' S, 144° 46' E, 22 May 1976, E. B. Britton (3 ANIC) ; Victoria, Lerderderg River , 6.8 km N Bacchus Marsh, wet gravel and cobbles at edge of small river; dry sclerophyll forest, elev. 135 m, 37° 37' S, 144° 25' E, 20 September 1999, N. Porch (64) (18 ANIC) ; McKillops Bridge, Snowy River , gravel at edge of large and rising river; dry sclerophyll forest, elev. 185 m, 37° 5' S, 148° 23' E, 6 November 2000, N. Porch (NP 16) (1 ANIC) .

Figures

FIGURES 11–14. Hydraena, dorsal and lateral habitus of holotypes. —11. H. magnetica. —12. H. miniretia. —13. H. innuda. —14. H. porchi.

FIGURES 15–18. Aedeagi of holotypes. —15. H. magnetica (after Zwick 1977). —16. H. miniretia. —17. H. innuda. —18. H. converga.