Batrachomatus wingii Clark, 1863

Hendrich, Lars & Balke, Michael, 2013, Revision of Australian Matini diving beetles based on morphological and molecular data (Coleoptera, Dytiscidae, Matinae), with description of a new species, ZooKeys 293, pp. 41-64 : 54-60

Batrachomatus wingii Clark, 1863

Batrachomatus wingii Clark, 1863: 15 (orig. descr.); Mouchamps 1964: 138 (descr.); Watts 1978: 120 (descr.); Watts 1985: 23 (cat.); Lawrence et al. 1987: 351 (cat.); Larson 1993: 50 (cat.); Nilsson 2001: 261 (cat.); Watts 2002: 31, 46 (cat.).

Type locality.

Northeast coast of Australia.

Holotype

♂: "N. Holl NE Aust 4412" [handwritten label], “Holotype”, "Batrachomatus wingi" [sic!], [blue handwritten label by Clark] (BMNH).

Additional materia

l (71 specimens).Western Australia: 1 ex., "Pilbara Region, De Grey River at Yarrie Station, 10.VII.1953, N.B.Tindale leg." (SAMA); 1 ex., "East Kimberley, Mitchell Plateau, Surveyors Pool, 150m, 17.VI.1999, Hendrich leg." (CLH). Northern Territory: 18 exs., "Kakadu N.P., Gungurul Lookout, 50 m, 13.59.359 S, 132.19.904E, 1.XI.1996, L. Hendrich leg. (Lok.11)" (CLH); 3 exs., "Finnis River, 10 km W Batchelor, 43m, 20.VIII.2006, 13.01.278S, 130.57.217E, L. & E. Hendrich leg." (NT 2), provided with green printed labels "DNA M.Balke 2773", "DNA M.Balke 2774", "DNA M.Balke 2775" (ZSM, CLH); 4 exs., "Kakadu NP, Gunlom Waterfall Area, 72m, 25.VIII.2006, 13.26.026S, 132.25.141E, L. & E. Hendrich leg." (NT 17), one specimen with green printed label "DNA M.Balke 1659" (ZSM); 20 exs., "Magela Creek upstream, Jabiru East, 38m, 29.VIII.2006, 12.40.458S,132.55.853E, L. & E. Hendrich leg." (NT 21) (CLH, NMW, ZSM); 1 ex., "Magela Creek downstream, Jabiru East, 31m, 30.VIII.2006, 12.38.312S, 132.53.441E, L. & E. Hendrich leg. (NT 23)", "DNA M.Balke 2772" [green printed label] (ZSM); 1 ex., "Daly River, H. Wesselmann" (SAMA); 4 exs., "Kakadu N.P., Jim Jim District, Jim Jim Falls Camping Area, Jim Jim Creek, 60 m, 13.16.218S, 132.49.276E, low-gradient stream, 26. & 27.X.1996, Hendrich leg./loc. 2a" (CLH);1 ex., "Kakadu N.P., Mary River District, 3 km ESE Gunlom Camping Area, South Alligator River, 50m, 2.XI.1996, 13.27.276S, 132.26.268E, L. Hendrich leg." (loc. 14) (CLH); 1 ex., "Fergusson River, 31 km SE by S of Pine Creek, 14.XI.1979, T.A.Weir leg." (ANIC). Queensland: 6 exs., "Foleyvale Aboriginal Reserve, 130 km W Rockhampton, 20.-25.I.1968, G. Hangay leg." (HNHM, CLH); 4 exs., "Boolburra, 95 km WSW Rockhampton, 12.I.1968, G. Hangay leg." (HNHM, CLH); 1 ex., "N Queensland, Bridge Creek, 20.XI.1992, water sweep, A. Calder & P. Zborowski leg." (ANIC); 1 ex., "N Queensland, Kennedy River Xing, dry river bed, sandy base, temporary pool, 16.VI.1992, T.A. Weir leg." (ANIC). Without any detailed locality label: 4 exs., “Australien”, "Sammlung Clemens Müller”, "Sammlung Zimmermann" (ZSM).

Literature records: Australia, Western Australia, Weaber Plain, Keep River east of Milligans, 15°37'11"S, 129°02'00"E, May 2009, A.W. Storey leg. ( WRM 2010); Australia, Northern Territory, Sandy Creek downstream of Keep River at Legune Road Crossing, 23.VII.-1.VIII.2004, 15°22'54"S, 129°11'43"E, A.W. Storey leg., site code SE 1, idem, Sandy Creek upstream of Keep River Road, 23.VII.-1.VIII.2004, 15°24'30"S, 129°11'33"E, A.W. Storey leg., site code SR 2 ( NCTWR 2005).

Description.

Measurements. TL = 6.9-7.8 mm, TL-H = 6.2-7.2 mm; MW = 3.2-3.7 mm.

Colour. Black, anterior part of head reddish brown, pronotum with broad yellow lateral margins, elytron with a narrow yellow band of which apical 1/3 close to side and basal 2/3 some distance from side (Fig. 7). Underside and parts of head reddish brown,appendages reddish brown.

Structure and sculpture. Body outline elongate oval, flattened, pointed apically. Dorsal surface shiny, head, pronotum and elytral surface densely and evenly covered with small punctures, reticulation absent. Serial punctures on elytron sparse, weakly impressed, indistinct. Sides of pronotum moderately curved and convergent anteriorly. Ventral surface very densely and minutely punctured. Prosternal process flat, broad, parallel-sided, weakly and narrowly grooved in midline, and weakly margined at side, tip bluntly pointed, apex pointed. Metacoxal lines well separated, subparallel, reaching almost to hind margin of metaventrite.

Male. Pro- and mesotarsi stouter than in female, furnished beneath with dense, short, stout setae arranged in groups, many of the setae ending in minute suction cups. Aedeagus: median lobe (Fig. 12 a, b); paramere (Fig. 12 c).

Affinities.

A very characteristic species and one of the most beautiful dytiscids in Australia (Fig. 7). Batrachomatus wingii differs from all other species of the genus in the narrower and more flattened shape of body, the dorsal yellowish longitudinal stripes on the elytra, the subparallel metacoxal lines and the shape of the median lobe.

Distribution.

Tropical northern Australia. Occurring from the northern Pilbara and the Kimberley region in the northwest, the Daly River, Darwin area and Kakadu National Park in the north, to the Atherton Tableland in northern Queensland, and along the east coast south to Rockhampton (Fig. 14).

Habitat.

Batrachomatus wingii occurs in seasonal and permanent lowland streams, creeks and slow flowing smaller rivers at an altitude from about 20 to almost 150 m, at least partly shaded by eucalypt woodland or monsoonal forest. Most specimens were found in low-gradient stream sections where the substratum was entirely coarse sand and smaller pebbles yet the current was strong enough to clear the bottom of silt and leaves (Figs 24, 25, 27). In this habitat the beetles were found in areas of medium, laminar flow, generally in deeper water (50 cm depth and more), along the outside curve of stream bend, among floating gum roots, under larger logs and stones. In the Northern Territory, at the end of the dry season, a larger series of the species was collected in the deepest, coldest and most oxygen rich part (50-80 cm depths) of a rest pool (10 m²), situated in a broad and almost dry and sandy creek bed. The pool was without any vegetation but rich in rotten leaves and partly shaded (Fig. 26). As mentioned by Larson (1993), who collected the species in northern Queensland at three different sites, the sub-surface seepage and local water temperatures could also be factors responsible for the local aggregation of beetles. In the Northern Territory larvae have been collected after the rainy season in February by Watts ( Alarie et al. 2001).

Habitats and faunistics

All Australian Batrachomatus species are strongly lotic and restricted to streams, creeks and rivers with sand, pebble and cobble beds, often situated in woodland or closed-canopy forest sites (Figs 16-27). It is probable that at least the larvae are sensitive to low levels of dissolved oxygen and require cooler temperatures. If this is so the occurrence of any Batrachomatus species can be considered a good indicator of a running water´s health, habitat and water quality.

The currently known altitudinal distribution and ecology of Batrachomatus species is shown in Table 1. Most species occur in lowland regions from almost sea level to 500 m. Only Batrachomatus daemeli has been collected in the Atherton Tableland and the Great Dividing Range up to at least 950 m. In Queensland Batrachomatus daemeli , Batrachomatus wingii and Batrachomatus larsoni sp. n.are sympatric. In eastern Victoria Batrachomatus daemeli and Batrachomatus wilsoni are known from the same area and in three rivers they are also syntopic. Batrachomatus daemeli is widespread along the east coast and south-eastern Australia, including the northeast of Tasmania, and Batrachomatus wingii occurs all over the tropical north of Australia. Two species, Batrachomatus nannup in the south west and Batrachomatus larsoni sp. n. in NE Queensland, have a very restricted distribution and are only known from one stream or river system (Blackwood River, Windsor Tableland). The rarity and limited distribution of the south-eastern Batrachomatus wilsoni might be the result of human impacts (irrigation, increasing of salinity, clearing of riverine forests) on almost all river systems in Victoria in the last five decades. All species seem to be capable of flight but none was ever obtained by operating light traps. The larvae of Batrachomatus daemeli and Batrachomatus nannup were recently described by Alarie et al. (2001). The larvae of Batrachomatus wilsoni , Batrachomatus larsoni sp. n. and Batrachomatus wingii remain unknown.

When in a net and out of the water specimensof Batrachomatus move very rapidly and are easily to recognise and to collect. In contrast, Larson et al. (2000) noted that the related Nearctic Matus are all lentic and occur along the margins of rather eutrophic ponds, often amongst Typha or decaying deciduous leaves. They are often slow to move and with their brownish colour are easily overlooked and consequently are not well collected. Despite the fact that all Australian species are capable of flight, none was obtained by operating light traps.

Key to Batrochomatus