Hydraena castanea Deane, 1937

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 : 28-29

Hydraena castanea Deane, 1937

( Figs. 37 , 41, 42 , 212, 227, 249)

Hydraena castanea Deane, 1937: 59 .

Hydraena castanea Deane ; Zwick, 1977: 160.

Type Material. Holotype (female): Victoria, Marysville. [labels: Marysville Deane // Type // Hydraena castanea, Deane. Det. C. Deane // DIGITAL IMAGE captured 2004 P. D. Perkins].

Differential Diagnosis. Similar in some external characters to H. clavigera ( Figs. 37, 39, 40 ); differing therefrom by the larger body size (ca. 1.70 vs. 1.50 mm), the wider and non-maculate pronotum, the more sparsely punctate pronotal disc, the less convex elytra, the slightly shorter (compared to width) last maxillary palpomere, and the narrower, more widely spaced plaques. The aedeagi of the two species show a similarity in basic plan, but differ distinctively in many details ( Figs. 41–44 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.75/0.73; head 0.30/ 0.43; pronotum 0.43/0.60, PA 0.43, PB 0.50; elytra 1.06/0.73. Dorsum dark brown, lateral areas of pronotum, shoulders of elytra and elytral apices lighter, legs brown, maxillary palpi testaceous, tips of palpi not lighter.

Frons punctures ca. 1xef; interstices shining, 1–2xpd. Clypeus microreticulate laterally, shining and very finely sparsely punctate medially. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae very weakly raised, lacking posterior ridge. Pronotal punctures on disc ca. 2xpd and deeper those of frons, interstices shining, anteriorly and posteriorly ca 1xpd, on disc ca. 3xpd; PF1 absent; PF2 shallow, oblique; PF3 moderately deep, broad; PF4 very shallow. Anterior margin of pronotum broadly emarginate.

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 conjointly rather sharply rounded, in posterior aspect margins form very weak angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/2/5/4. P1 laminate; median carina angulate in profile. P2 narrow, l/w ca. 5/2, sides parallel, apex blunt. Plaques parallel, not raised, located on each side of deep depression. No midlongitudinal carina between mesoventral intercoxal process and plaques. Carina behind mesocoxae strong. AIS flat, width at arcuate posterior margin ca. 2x P2. All femora thickened. Protibia (male) widest at midlength, excavate on inner surface, prominent spine at beginning of excavation. Mesotibia simple. Metatibia nearly straight, very weakly emarginate on inner surface over distal 3/4. Last sternite almost symmetrical; last tergite notched apicomedially.

Aedeagus ( Figs. 41, 42 ) main-piece with distal part extended on both left and right sides, right side process in two parts, one "above" the other; distal piece with long gonopore-bearing flagellum to left of which (ventral view) is narrow process; left paramere moderately wide in lateral aspect, setae at apex and small group of short setae on dorsal margin subapically; right paramere bisinuate, setae in two groups. Female last tergite with apicomedian incision, delimiting two lobes, setae slender, tapering; gonocoxite and spermatheca as illustrated (Figs. 212, 227).

Distribution. Currently known from Victoria, Australian Capital Territory, and New South Wales (Fig. 249).

Remarks. The holotype is a female; I have drawn the aedeagus of a specimen from Victoria, Tarra-Bulga National Park.

Material Examined (657): Australian Capital Territory, Blundells Ck. 3 km E of Piccadilly Circus, flight intercept window/trough trap, elev. 850 m, 35° 22' S, 148° 50' E, 1 January–30 March 1984, Weir, Lawrence, Johnson (3 ANIC); Wombat Creek, 6 km NE of Piccadilly Circus, flight intercept window/trough trap, elev. 750 m, 35° 19' S, 148° 51' E, 1–30 March 1985, Weir, Lawrence, Johnson (1 ANIC); New South Wales, 10.5 km W Kangaroo Valley, Barrengarry Mtn., litter along intermittent stream, FMHD #83-217, 34° 39' S, 150° 29' E, 10 June 1983, L. E. Watrous (4 FMNH); Cabbage Tree Creek, Canberra/ Coast Road, gravel and sand at edge of small densely shaded stream in sclerophyll forest, elev. 85 m, 35° 34' S, 150° 2' E, 22 July 2000, N. Porch (93) (2 ANIC); Clyde Mt., rainforest litter, 35° 32' S, 149° 57' E, 3 March 1968, J. Balderson (1 ANIC); Clyde Mt. (summit), ANIC Berlesate No. 658, 35° 32' S, 149° 57' E, 27 September 1979, I. D. Naumann & J. C. Cardale (33 ANIC); 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) (1 FMNH); Headwaters of Nullica River, headwater stream, 37° 4' S, 149° 47' E, 24 June 1997, J. & R. Miller (site 659) (2 ANIC); same locality, 37° 4' S, 149° 47' E, 10 June 1999, J. & R. Miller (site 659) (7 ANIC); Mt. Wilson, rainforest litter nr. stream, FMHD #83-276, 33° 30' S, 150° 22' E, 18 July 1983, L. E. Watrous (5 FMNH); New England N. P., Berlesate ANIC 863, Nothofagus moorei litter, 30° 40' S, 152° 23' E, 15 November 1982, J. Doyen (1 ANIC); New England N. P., Robinson’s Knob Rd., 1 km E Park gate, Nothofagus moorei forest, level, wet leaves and flood debris, forest stream, FMHD #87-156, elev. 1305 m, 30° 30' S, 152° 24' E, 14 January 1987, A. Newton & M. Thayer (780) (14 FMNH); Royal N. P., Palm Gully, off Lady Wakehurst Drive, subtropical rainforest, wet leaves & flood debris, forest stream, FMHD #86-669, elev. 80 m, 34° 9' S, 151° 2' E, 25 December 1986, A. Newton & M. Thayer (774) (4 FMNH); Unnamed creek drains into Crawleys Creek, 36° 56' S, 149° 43' E, 13 June 1999, J. & R. Miller (site 731) (11 ANIC); Unnamed creek drains into Nullica River, 37° 4' S, 149° 46' E, 11 October 1997, J. & R. Miller (site 661) (30 ANIC); same locality, 37° 4' S, 149° 46' E, 25 October 1999, J. & R. Miller (site 661) (18 ANIC); Unnamed creek drains into Nungatta Creek, 36° 7' S, 149° 29' E, 11 February 1998, J. & R. Miller (site 566a) (1 ANIC); same locality, 21 February 1998, J. & R. Miller (site 566a) (2 ANIC); same locality, 22 February 1998, J. & R. Miller (site 566b) (4 ANIC); same locality, 23 February 1998, J. & R. Miller (site 566d) (38 ANIC); same locality, 23 February 1998, J. & R. Miller (site 566c) (75 ANIC); same locality, 12 February 2000, J. & R. Miller (site 566b) (19 ANIC); same locality, 13 February 2000, J. & R. Miller (site 566d) (18 ANIC); same locality, 13 February 2000, J. & R. Miller (site 566c) (32 ANIC); same locality, 16 February 2000, J. & R. Miller (site 566e) (6 ANIC); same locality, 24 February 2000, J. & R. Miller (site 566e) (5 ANIC); Unnamed creek drains into Old Hut Creek, 37° 1' S, 149° 46' E, 18 June 1997, J. & R. Miller (site YNP) (2 ANIC); same locality, 37° 1' S, 149° 46' E, 12 October 1997, J. & R. Miller (site YNP) (1 ANIC); same locality, 37° 1' S, 149° 46' E, 12 June 1999, J. & R. Miller (site YNP) (75 ANIC); same locality, 37° 1' S, 149° 46' E, 23 October 1999, J. & R. Miller (site YNP) (8 ANIC); Unnamed creek drains into Yowaka River, 36° 57' S, 149° 43' E, 26 June 1997, J. & R. Miller (site 717) (11 ANIC); same locality, 36° 57' S, 149° 43' E, 15 June 1999, J. & R. Miller (site 717) (25 ANIC); Victoria, Baw Baw Alpine Res., entrance gate, Eucalyptus spp. forest, berl., wet debris, forest stream, elev. 720 m, 37° 51' S, 146° 14' E, 26 February 1993, A. Newton & M. Thayer (5 FMNH); Big Tree Creek, at Tanjil River, East Branch, 4 km SE of Tanjil Bren, littery sand at edge of small roadside section of creek; wet sclerophyll forests surrounds, elev. 495 m, 37° 49' S, 146° 11' E, 10 December 2000, N. Porch & R. Porch (NP 07) (2 ANIC); Delatite River below Sawmill Settlement, 37° 7' S, 146° 12' E, 24 February 1972, Hynes (1 PZC); Faith Creek, 5 km SW of Mt. Baw Baw, ex. water splashed rocks in small cascading montane creek beside road; Nothofagus rainforest/wet sclerophyll forest, elev. 600 m, 37° 52' S, 146° 14' E, 2 December 1999, N. Porch (44) (5 ANIC); Gembrook, south of, muddy litter of small mud/sand banks of small, shaded, forest stream; wet sclerophyll forest, elev. 245 m, 37° 55' S, 145° 32' E, 8 April 2000, N. Porch & N. Krause (NP 63) (7 ANIC); Godfrey’s Creek above AI Mine Settlement, 38° 36' S, 143° 54' E, 23 April 1972, Hynes (1 PZC); same locality, 38° 36' S, 143° 54' E, 11 October 1972, P. Zwick (1 PZC); Loddon Falls, base of, NE of Glenlyon, sandy gravel at edge of waterfall splashpool in scrubby gorge [stream], elev. 470 m, 37° 16' S, 144° 14' E, 16 March 2001, N. Porch & K. Sniderman (19) (1 ANIC); Loddon River at Guildford, sand and sandy mud at edge of small stream in pastureland, elev. 235 m, 37° 9' S, 144° 9' E, 17 February 2002, N. Porch (86) (1 ANIC); Marysville [no date], 37° 30' S, 145° 52' E ,, Deane (2 UQIC); Merriman Creek, 2.0 km NW Seaspray, gravel at base of gravel bank of small creek; pasture, elev. 5 m, 38° 21' S, 147° 9' E, 7 April 1999, N. Porch & N. Krause (50) (1 ANIC); Mt. Buffalo N. P., above Eurobin Point, wet sclerophyl forest, wet debris at waterfall base, elev. 820 m, 36° 42' S, 146° 50' E, 23 January 1987, A. Newton & M. Thayer (805) (2 FMNH); Mt. Donna Buang, 0.5 km below 10 mile turntable, along small forest stream, elev. 1005 m, 37° 42' S, 145° 40' E, 14 January 1980, A. Newton & M. Thayer (1 USNM); Mt. Donna Buang, 0.5 km below 10 mile turntable, flood debris, forest stream, elev. 1005 m, 37° 42' S, 145° 40' E, 14 January 1980, A. Newton & M. Thayer (56 USNM); Mt. Donna Buang, 0.5 km below 10 mile turntable, wet moss, stream edge, elev. 1005 m, 37° 42' S, 145° 40' E, 14 January 1980, A. Newton & M. Thayer (28 USNM); Tanjil R., E. Branch, 4 km SE Tanjil Bren, wet scleroph./ Nothofagus cun- ninghamii, wet leaves and flood debris, forest stream, FMHD 87-263, elev. 490 m, 37° 50' S, 146° 12' E, 10 February 1987, A. Newton & M. Thayer (829) (2 FMNH); Tarra Valley Road, 1.5 km SE Tarra Falls, Tarra- Bulga N. P., small shallow rill (mm's) flowing over road-cutting at edge of road in wet sclerophyll forest ( Eucalyptus regnans ), elev. 240 m, 38° 28' S, 146° 33' E, 13 January 1999, N. Porch (NP 13) (5 ANIC); Tarra- Bulga N. P., Bulga, near suspension bridge, Nothofagus cunninghamii / Eucalyptus regnans , berl. leaf and log litter, forest floor, FMHD #87-260, elev. 600 m, 38° 26' S, 146° 34' E, 7 February 1987, A. Newton & M. Thayer (8 FMNH); Warburton, Cement Creek, flood debris, forest stream, elev. 670 m, 37° 42' S, 145° 44' E, 10–17 January 1980, A. Newton & M. Thayer (61 USNM); Warburton, Cement Creek, wet moss, stream edge, Nothofagus cunninghamii , etc., elev. 670 m, 37° 42' S, 145° 44' E, 10–17 January 1980, A. Newton & M. Thayer (8 USNM).

Figures

FIGURES 37–40. Hydraena, dorsal and lateral habitus. —37. H. castanea, holotype. —38. H. tricantha, holotype. —39. H. clavigera, holotype. —40. H. clavigera, specimen from Queensland, Mt. Hypipamee National Park.

FIGURES 41–44. Hydraena, aedeagi. —41. H. castanea, holotype (after Zwick 1977). —42. H. castanea, specimen from Victoria, Tarra-Bulga National Park. —43. H. clavigera, holotype (after Zwick 1977). —44. H. clavigera, specimen from Queensland, Mt. Hypipamee National Park.