Hydraena hynesi 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 : 39-40

Hydraena hynesi Zwick, 1977

( Figs. 54, 56 , 57 , 243)

Hydraena hynesi Zwick, 1977: 165 .

Type Material. Holotype (male): Victoria, Aberfeldy River on road from Woods Point to Walhalla [labels: Australia, Vic., Aberfeldy R., 27.i.1972 Hynes // Hydraena hynesi Zwick Holo-Typus des. P. Zwick 1977 // HOLOTYPE T-12800 Hydraena hynesi Zwick, 1977 // DIGITAL IMAGE captured 2004 P. D. Perkins]. Deposited in the MVMA.

Differential Diagnosis. Similar to H. cunninghamensis in body size, coloration, and the confluent pronotal foveae PF2, forming a U-shaped impression ( Figs. 57 , 99); differing therefrom by the less coarsely punctate pronotum (compared to the frons), and the narrower plaques. The aedeagi of the two species distinctively differ ( Figs. 56 , 102).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.38/0.60; head 0.17/ 0.33; pronotum 0.34/0.46, PA 0.38, PB 0.36; elytra 0.84/0.60. Dorsum bicolored, clypeus and pronotum testaceous, frons and elytra brown except diffuse lighter area on elytral disc, legs and maxillary palpi testaceous (but see notes).

Frons punctures ca. 1xef; interstices shining, 0.5–3xpd; posterior margin in form of arcuate step-like ridge (fits against anterior margin of pronotum), area posterior to ridge markedly microreticulate. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum shining, very finely sparsely punctate; postmen- tum microreticulate. Genae raised, lacking posterior ridge. Pronotum cordiform, anterior margin emarginate; punctures on disc ca. 1–2xpd than those of frons, interstices shining, 2–4xpd, punctures denser at anterior; PF1 united to form shallow transverse impression across anterior 1/3 of pronotal disc; PF2 well impressed, oval, oblique, shallowly united in middle, conjointly forming U-shaped impression; PF3 moderately shallow, broad; PF4 very shallow.

Elytra distinctively humped just behind midlength, at summit of posterior declivity; on basal 1/3 punctures large ca. 2–3xpd largest pronotal punctures, some random, some forming side-by-side contiguous pairs, punctures becoming more serial and gradually smaller toward posterior. Intervals not raised, shining, width over posterior 0.6 ca. 2xpd, as are interstices between punctures of a row. Apices in dorsal aspect gradually separately rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.2/2/2. P1 with median carina straight in lateral view. P2 as wide as area separating anterior extreme of plaques, short, l/w ca. 1/1, sides parallel, apex blunt. Plaques narrow lines, located in posterior 7/10 of metaventrite on sides of deep median depression, plaques convergent anteriorly, separation anteriorly 1x P2, separation posteriorly 2x P2. Low, very short midlongitudinal carina between mesoventral intercoxal process and plaques. AIS large, flat, width at straight posterior margin 2x P2. Protibia slender, weakly arcuate, inner surface with prominent narrow triangular process just past midlength. Profemur with small tubercle at base. Meso- and metatibia slender, straight or nearly so. Last sternite symmetrical or nearly so; last tergite with deep, narrow, apicomedian notch.

Aedeagus ( Fig. 56 ) main-piece widened distally (ventral view), with strong process on right side at distal extreme; distal piece with short, strong, hook-shaped process, small fimbriate lobe, and characteristically shaped apicomedian process that has short gonopore-bearing flagellum; left paramere displaced medially, with row of medially directed setae; right paramere shorter than left, inserting slightly more distally than left paramere. Female last tergite with apicomedian incision, delimiting two lobes, setae slender, tapering.

Distribution. Widely but very sparsely distributed from Victoria to Queensland (Fig. 243).

Remarks. The color varies from distinctively bicolored (e.g., the holotype) to uniformly dark brown, sometimes with a reddish tint.

Material Examined (157): New South Wales, Back Creek, Moffatt Falls, ca. 5 km W New England N. P. boundary, ex. seepage rockface at side of Moffatt Falls , 30° 29' S, 152° 20' E, 24 January 1998, P. D. Perkins (1 MCZ); Chichester S. F. (nr. Dungog), Hotel Ck. & Bush Mill Rd. , gallery subtrop. rainforest, wet leaves and flood debris, forest stream, FMHD #87-155 , elev. 500 m, 32° 12' S, 151° 43' E, 16 January 1987, A. Newton & M. Thayer (3 FMNH); Dorrigo N. P., Rosewood Creek, upstream from Coachwood Falls, ex. gravel/sand stream bank, elev. 650 m, 30° 22' S, 152° 40' E, 26 January 1998, P. D. Perkins (2 MCZ); Dorrigo N. P., Sassafras Creek , upstream from Casuarina Falls , ex. bare rocks in splash zone, elev. 650 m, 30° 22' S, 152° 40' E, 27 January 1998, P. D. Perkins (5 MCZ); Dorrigo N. P., south slope Dome Mt. , subtropical rainforest, wet leaves and flood debris, forest stream, FMHD #86-682 , elev. 720 m, 30° 21' S, 152° 46' E, 28 December 1986, A. Newton & M. Thayer (778) (3 FMNH); Dorrigo N. P., Callicoma Falls, wet leaves and flood debris, elev. 750 m, 30° 20' S, 152° 24' E, 5 March 1980, A. Newton & M. Thayer (32 USNM); Unnamed creek drains into Crawleys Creek , 36° 56' S, 149° 43' E, 22 June 1997, J. & R . Miller (site 731) (1 ANIC); Unnamed creek drains into Nungatta Creek , 36° 7' S, 149° 29' E, 21 February 1998, J. & R . Miller (site 566a) (6 ANIC); same locality, 23 February 1998, J. & R . Miller (site 566d) (1 ANIC); same locality, 11 February 2000, J. & R . Miller (site 566a) (5 ANIC); same locality, 12 February 2000, J. & R . Miller (site 566c) (6 ANIC); same locality, 12 February 2000, J. & R . Miller (site 566b) (7 ANIC); Unnamed creek drains into Old Hut Creek , 37° 1' S, 149° 46' E, 18 June 1997, J. & R . Miller (site YNP) (3 ANIC); same locality, 37° 1' S, 149° 46' E, 12 October 1997, J. & R . Miller (site YNP) (5 ANIC); same locality, 37° 1' S, 149° 46' E, 12 June 1999, J. & R . Miller (site YNP) (13 ANIC); same locality, 37° 1' S, 149° 46' E, 23 October 1999, J. & R . Miller (site YNP) (11 ANIC); Unnamed creek drains into Yowaka River , 36° 57' S, 149° 43' E, 26 June 1997, J. & R . Miller (site 717) (10 ANIC); Wiangaree SF, Brindle Creek , wet leaves and flood debris, subtrop. for- est, elev. 740 m, 28° 22' S, 153° 0' E, 29 February to 3 March 1980, A. Newton & M. Thayer (28 USNM); Wiangaree SF, Isaksson Ridge, berl. forest leaf & log litter, N. moorei rainfor., elev. 1050 m, 28° 22' S, 153° 0' E, 29 February to 3 March 1980, A. Newton & M. Thayer (4 USNM) ; Queensland, Cedar Creek, 27° 53' S, 153° 10' E, 22 August 2004, A. Glaister (3 NMW); Lamington, Binna Burra, Comera River, stones, 28° 15' S, 153° 6' E, 17 November 1982, Endrödy-Younga (AU 73) (1 TMSA); National Park, Macpherson Range, 22° 17' S, 146° 18' E, 1 January 1928, Carter (1 UQIC); Natural Bridge N. P., Cave Creek , ex. bare rocks in splash zone, 28° 14' S, 153° 15' E, 31 January 1998, P. D. Perkins (1 MCZ) ; Victoria, Aberfeldy River, Donnelly’s Creek Track, NMV Survey Dept. GRES T18 no. 5146, 37° 42' S, 146° 23' E, 29 November 1976, [collector not given] (1 UQIC); Aberfeldy River on road from Woods Point to Walhalla , 37° 39' S, 146° 26' E, 27 October 1971, Hynes (1 NMW, 1 PZC); same locality, 37° 39' S, 146° 26' E, 27 January 1972, Hynes (1 PZC) .

Figures

FIGURES 53–56. Hydraena, aedeagi of holotypes. —53. H. antaria. —54. H. hynesi. —55. H. luminicollis. —56. H. hynesi (after Zwick 1977).

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