Hydrocanthus (Sternocanthus) pederzanii, Toledo & Hendrich, 2006

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 : 938-939

Hydrocanthus (Sternocanthus) pederzanii sp.n. ( Figs 2 , 8 , 13 , 17 )

Type locality: Mitchell Lake, Atherton Tableland, Northern Queensland, Australia.

Type material: Holotype: 1: " Queensland, Atherton tableland, Lake Mitchell , 21.XI.1998, F. Pederzani leg." ( ANIC) . Paratypes: 11 specimens with same data as holotype ( FPR, MTP, CHB, PMB) ; 2: " Australia, QLD01/19 Mt. Eliott NP, 200m 4.- 6.4.2001 M. Baehr " ( CHB, ZSM) .

D i a g n o s i s: Very large species (the largest in Australasia; comparable in size with some African Hydrocanthus ), oblong, convex, colouration uniformly black. Dorsal surface weakly iridescent ( Fig. 2 ).

D e s c r i p t i o n: Holotype: total length: 7.6 mm; total length without head: 6.8 mm; maximum width: 3.6 mm. Paratypes: total length: 6.3-7.7 mm; total length without head: 5.8-7.0 mm; maximum width: 3.2-3.7 mm.

Head: brownish-black, dorsal microreticulation as on the preceding species, a little less impressed. Underside and labrum dark brown, antennae and mouthparts reddish.

Pronotum: pitch-black; slightly faded on lateral sides; poorly iridescent; lateral sides rounded, with bead strong and in relief, gradually narrowed to the base; anterior bead quite strong. Dorsal surface with wrinkles of meshes.

Elytra: black, weakly iridescent but more shining than H. balkei . Maximum width close to the base; microreticulation as on pronotum but a bit more impressed; two longitudinal series of dots run on elytral surface as on H. balkei .

Underside: uniformly brown; surface covered by a sculpture of strong polygonal meshes. Prosternum and prosternal process strongly pubescent; hair dots on prosternum a bit more closer than on prosternal process. Legs: reddish-brown.

: Median lobe of aedeagus ( Fig. 8 ) similar as in H. balkei , but slender, more regularly tapering toward the apex; transverse ridge on left side less visible. Left paramere ( Fig. 13 ) as in the preceding species, but more rounded at the apex.

: Similar to, not differing from male externally. E t y m o l o g y: Dedicated to our friend and colleague Fernando Pederzani (Ravenna, Italy), who collected most of the type material.

H a b i t a t: The Mitchell Lake is a great shallow lake on the Atherton tableland. According to Pederzani (in litt.) all beetles were collected in very shallow water at the shore, which was sinuate in that place, with emergent water plants. The specimens from Mount Eliott were collected at light (Baehr pers. com).

D i s t r i b u t i o n ( Fig. 17 ): North-eastern Queensland, Australia. In hilly regions from Mitchell Lake in the north to Mt. Eliott National Park near Townsville in the south. This species seems to be quite rare and localised. The two specimens known from Mt. Elliot are smaller (6.3-6.4 mm; 5.8-6.0 mm without head) compared with the series from Mitchell Lake (7.3-7.7 mm; 6.7-7.0 mm without head) .

N o t e s: The two new species, H. balkei and H. pederzanii , seem to be more closely related respect to the other Australian species of Hydrocanthus , due the similar reticulation of dorsal surfaces, the punctuation of prosternum and prosternal process and the shape of median lobe of aedeagus. They both have – apparently – isolated and pointlike distributions ( Fig. 17 ); such distributions give the appearance to be relict and this, together with their closeness, might suggest a common origin from an ancestor with a wider distribution, later broken up and speciated into the extant species.

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.

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).