Hydrocanthus (Sternocanthus) australasiae WEHNCKE 1876

Toledo, M. & Hendrich, L., 2006, Taxonomic revision of the Australasian Hydrocanthus SAY 1833, with description of two new species (Coleoptera: Noteridae), Linzer biologische Beiträge 38 (1), pp. 935-952 : 939-940

Hydrocanthus (Sternocanthus) australasiae WEHNCKE 1876 ( Figs 3 , 9 , 14 , 18, 19, 20 )

Hydrocanthus australasiae WEHNCKE 1876: 223 (orig. descr.).

Hydrocanthus australasiae WEHNCKE 1876 - SHARP 1882: 279; BRANDEN 1885: 18; ZIMMERMANN 1919: 118; 1920: 14; WATTS 1985: 27; LAWRENCE et al. 1987: 327; LARSON 1993: 60; 1997: 273; WATTS 2001: 61; 2002: 51-55.

Hydrocanthus (Sternocanthus) australasiae WEHNCKE 1876 - BAMEUL 1994: 362; NILSSON & VONDEL 2005: 114.

Type locality: Rockhampton, Queensland, Australia. Type material: Lectotype: Female ( MNHN), here designated: glued on small, triangular card, labelled: "Daemel [small, white, rectangular, black bordered label, handwritten] / Nov Holld [= Nova Hollandia] Rockhampton [slightly larger, rectangular, mauve label, black bordered, handwritten]". Paralectotypes: 9 exs. ( MNHN) unlabelled. M a t e r i a l e x a m i n e d: AUSTRALIA: Northern Territory: 1 ex.: Northern Territory, Kakadu

N.P., Jim Jim Falls camping area, 60 m, 26-27.XI.1996, S13°16.218' E132°49.276', L. Hendrich

leg. ( CHB); 1 ex.: Northern Territory, Kakadu N.P., Arnhem Hwy, 12 km WNW Jabiru , ca. 50 m ,

29.XI.1996, S12°37.937 E 132°38.134. L. Hendrich leg. ( CHB) ; 16 exs.: Fogg Dam/Darwin,

30.VIII.1986, S. Kiener leg. ( NHMB). Queensland: 10 exs.: N Queensland, 20 km E of

Normanton, II.1996, at light, S. Lamond leg. ( CHB) ; 15 exs.: N Queensland, 20 km E of

Normanton , I.1996, at light, riverside ( CHB) ; 10 exs.: Cape York, VI.1993, leg. Uhler ( GWW) ; 10

km S Tully, S Innisfajl, 30 m, 25.I.1993, G. Wewalka leg. (12 exs. GWW, FPR). Western

Australia: 1 ex.: W Australia, Shire of Wyndham, E Kimberley, Gibb River Road, creek 10 km W

Bindoola Creek , 13.VI.1999, L. Hendrich leg., WA 5/105 ( CHB) ; 1 ex.: Shire of Derby, W

Kimberley, Gibb River Road, Manning Gorge, 400 m, 20.-21.VI.1999, L. Hendrich leg., WA

18/118 ( CHB); 1 ex.: Shire of Wyndham , E Kimberley, Gibb River Road, King Edward River

Crossing, 280 m, 15.VI.1999, Hendrich leg., WA 10/110 ( CHB) ; 10 exs.: Shire of Wyndham , East

Kimberley, Mitchell Plateau, Little Mertens Falls, 300 m, 15.VI.1999, Hendrich leg., WA 11a/111a

( CHB, MTP); 17 exs.: Shire of Derby - West Kimberley, Gibb River Road , Galvans Gorge , 420 m ,

21.VI.1999, Hendrich leg., WA 19/119 ( CHB) ; 1 ex.: Shire of Wyndham , East Kimberley ,

Mitchell Plateau, Port Warrender Road / Kalumburu Road, Lowya Creek, 290 m, 18.VI.1999,

Hendrich leg., WA 13/113 ( CHB) ; 7 exs.: Shire of Derby, West Kimberley, Gibb River Road ,

Saddler Spring near Iminji Aboriginal Community, 350 m, 22.VI.1999, Hendrich leg., WA 20/120

( CHB, MTP); 2 exs.: E Kimberley, Mt. Barnett , Manning River, S 016°39'22 E 125°55'43.5 ,

18.VII.1998, Dr. W.G. Ullrich leg. ( NHMB).

D i a g n o s i s: Oblong-oval, poorly convex, more gently tapering toward the elytral apex. Coloration uniformly blackish-brown. Dorsal surface glossy, weakly iridescent. Median lobe of aedeagus distinctive ( Fig. 3 ).

D e s c r i p t i o n: total length: 5.7-6.6 mm (lectotype: 6.6 mm); total length without head: 5.0- 5.9 mm (lectotype: 5.9 mm); maximum width: 2.75-3.1 mm (lectotype: 3.1 mm).

Head: brownish-black, dorsal reticulation quite fine, arranged in irregular wrinkles, together with very scarce, scattered, small dots. Underside and labrum dark brown, antennae and mouthparts reddish.

Pronotum: pitch-black, reddish-brown in some specimens; poorly iridescent. Dorsal surface with a fine microreticulation of wrinkles composed by hardly discernible meshes.

Elytra: pitch-black or dark brown; poorly iridescent, more shining than the two preceding species. Maximum width just close to the base; microreticulation as on pronotum; two regular series of longitudinal dots run on basal half of the elytra, more irregular on the distal half.

Underside: brown or reddish-brown; surface covered by a sculpture of strong polygonal meshes. Prosternum and prosternal with hair dots more scattered than in H. balkei and H. pederzanii ; hair punctures less dense on metasternum and metacoxal process. Legs: reddish-brown.

: Median lobe of aedeagus ( Fig. 9 ) blunt, rounded apically; transverse ridge on left side very pronounced and deep. Left paramere as in Fig. 14 .

: Similar to, not differing from male externally.

H a b i t a t: According to LARSON (1997) a more lentic species occurring in billabongs, reservoirs and rest pools of intermittent streams. In Western Australia collected at the edge of large, slow flowing and deep (up to 2 m depth) permanent rivers, shaded by old riverine Pandanus aquaticus and Melaleuca trees. The beetles are often found in shallow (15 cm), isolated and half-shaded riverine puddles or embayments among roots and organic debris like rotten leaves twigs and grasses ( Fig. 20 ). At Galvan´s Gorge ( Fig. 18 ) in a rocky, shallow (25 cm) and very slow flowing stream, partly shaded by mixed Pandanus and Melaleuca forest and overgrown with grass tussocks and Nymphaea violacea ( Fig. 19 ). At this side syntopic with H. waterhousei and Canythdrus ephemeralis WATTS 2001. Also attracted to light.

D i s t r i b u t i o n ( Fig. 17 ): Tropical north of Australia. From the Kimberley Plateau in Western Australia, Kakadu National Park in the Northern Territory to the Atherton Tableland and White Mountains National Park in north-eastern Queensland ( LAWRENCE et al. 1987, LARSON 1993, 1997; WATTS 2001, WEIR 1998). South to northern New South Wales ( WATTS 2002).

Figures

Figs 1-6: Habitus of: (1) Hydrocanthus balkei; (2) H. pederzanii; (3) H. australasiae; (4) H. waterhousei; (5) indicus, f. typica; (6) indicus, black form (scale: 2 mm).

Figs 7-11: Median lobes of aedeagus (left lateral view, rotated): (7) Hydrocanthus balkei; (8) H. pederzanii; (9) H. australasiae; (10) H. waterhousei; (11) H. indicus.

Figs 12-16: Left paramere (inner face, rotated): (12) Hydrocanthus balkei; (13) H. pederzanii; (14) H. australasiae; (15) H. waterhousei; (16) H. indicus.

Figs 18-20: Habitats of Hydrocanthus in northern Australia: (18, 19) Galvan´s Gorge, Western Australia, East Kimberley. Habitat of numerous Dytiscidae and the Noteridae Hydrocanthus australasiae, H. waterhousei and Canthydrus ephemeralis WATTS 2001; (20) King Edward River Crossing, Kimberley Plateau, Western Australia. Habitat of H. australasiae.

Fig. 17: Distribution of the Australasian species of the genus Hydrocanthus (Sternocanthus) after LARSON (1993, 1997), WEIR (1998) and specimens cited in this publication. Hydrocanthus australasiae (triangles), H. waterhousei (asteriks), H. balkei (square) and H. pederzanii (dots).