Antiporus kalbarriensis, Hendrich, Lars & Watts, Chris H. S., 2010

Hendrich, Lars & Watts, Chris H. S., 2010, An endemic predaceous water beetle from the Murchison River in Western Australia — Antiporus kalbarriensis sp. n. (Coleoptera: Dytiscidae, Hydroporinae, Hydroporini), Zootaxa 2338, pp. 35-42 : 38-39

Antiporus kalbarriensis sp.n.

Figs 2, 4 , 5 , 6 , 7, 8

Type locality. Western Australia, 24 km N Binnu [27°33´S 114°25´E], Murchison River, backwater pool.

Type material. Holotype: Male: “WA Murchison River 24 k N Binnu 18/5/01 C.H.S. Watts”, “ HOLOTYPE Antiporus kalbarriensis sp.n. Hendrich & Watts des. 2009” [red label, printed] ( WAM). Paratypes: 2 males and 2 females; same locality data as holotype and “ PARATYPE Antiporus kalbarriensis sp.n. Hendrich & Watts des. 2009” [red label, printed] ( SAMA, CLH); 1 female: “ DNA M. Balke 2704” [green label, printed], “ AUSTRALIA, WA, Batavia Coast, Kalbarri N.P., Ross Graham Lookout, 5.9.2002, 27°33´S 114°25´E, Hendrich leg./Loc. 19/183”, “ PARATYPE Antiporus kalbarriensis sp.n. Hendrich & Watts des. 2009” [red label, printed] ( CLH).

Etymology. Named after the Kalbarri National Park where part of the type material was collected.

Description. Measurements. TL = 3.6–3.8 mm (holotype 3.8 mm); TL-H = 3.3–3.5mm (holotype 3.5 mm); MW = 1.95–2.05 mm (holotype 2.0 mm).

Colour. Upper side yellowish-brown; portions of elytron and sutural lines a bit darker, sutural lines broadly bordered with broad pale strip, apical portions lighter ( Fig. 2 ). Venter yellowish, including pronotum, epipleuron, metaventrite, metacoxal plate, prosternal process, legs and abdominal sternites. All antennomeres completely pale yellowish.

Sculpture. Dorsal surface strongly, densely and evenly punctured throughout; those on head weaker and sparser, a little smaller than eye facet. Pronotum and elytron with narrow but well marked lateral beading. Microreticulation on head and pronotum fine, moderately impressed, on elytron very fine and almost unvisible. Ventral surface; punctures very dense, microreticulation similar to that on elytron. Prosternal process narrowly lanceolate, rounded tip, almost keeled in cross section, slightly narrowed between procoxae. Metacoxal lines raised, moderately separated, subparallel in posterior half, diverging to about twice their narrowest width in anterior half.

Male. Protarsi moderately expanded, robust; single proclaw thickened, strongly bent near base, continously narrowing to sharp point at apex, with slightly curved large tooth at base ( Fig. 5 ). Mesotibia robust, broadly but weakly indented on inner side in middle. Seta tufts on mesotrochanters somewhat thicker than on female. Median lobe of aedeagus in lateral view rather thin, elongated, in ventral view symmetric tapering towards tip ( Fig. 4 ).

Female. Pro- and mesotarsi narrower than in males, not expanded. Proclaws simple. Mesotibia narrow.

Affinities. The new species appears closest to A. bakewellii , A. jenniferae and A. simplex . From A. bakewellii (TL = 3.1–3.45 mm) ( Figs 1, 3 ) it differs by its larger size, less marked and more diffuse elytral colour pattern, the more parallel sided and elongated form of the median lobe, and the robust and well developed spine at the base of the claw on the male protarsi (compare Watts 1978: 65 and Watts 1997: 39). From the smaller A. jenniferae (TL = 3.4–3.6 mm) it can be distinguished by its yellowish tarsi (totally black in A. jenniferae ), and the form of the aedeagus which is slender and tapering to the tip in A. kalbarriensis sp.n.. From the slightly smaller (TL = 3.5–3.7 mm) A. simplex Watts, 1978 from Queensland, A. kalbarriensis sp.n. can be well separated by its more elongated median lobe of aedeagus, which is more tapered at the tip, and its larger and more robust spine at the base of the claw on the male protarsi as well as a stronger dorsal colour pattern which is virtually absent in A. simplex (compare Watts 1978: 65 and Watts 1997: 39). In the key given in Watts 1997 the species will run to couplet 7.

Distribution. Western Australia, Murchison District. Only known from two localities along the Murchison River ( Fig. 6 ).

Habitat. At both localities the specimens were collected from half-shaded (sedges at the banks), shallow, sandy backwater pools, with dense mats of Chara and other floating vegetation, beside the Murchison River ( Fig. 7 ). The bottom consisted of fine sand with a thin layer of mud and plant debris ( Fig. 8 ). Apart from the Antiporus , the water beetle coenosis included the following species: Murchison River north of Binnu: Haliplidae : Haliplus sp.n. ( Watts & MacRae 2010); Dytiscidae : Hyphydrus elegans (Montrouzier, 1860) , H.

lyratus Swartz, 1808; Hydrophilidae : Berosus dallasi Watts, 1987 , Enochrus elongatus (W.J. Macleay, 1873) , E. maculiceps (W.J. Macleay, 1873) . Ross Graham Lookout: Dytiscidae : Allodessus bistrigatus (Clark, 1862) , Antiporus gilberti (Clark, 1862) , Eretes australis (Erichson, 1842) , H. elegans , Limbodessus inornatus (Sharp, 1882) , Megaporus howittii (Clark, 1862) , Necterosoma penicillatum (Clark, 1862) N. regulare Sharp, 1882 , Rhantus suturalis (W.S. Macleay, 1825) ; Hydrophilidae : Enochrus eyrensis (Blackburn, 1894) , Limnoxenus zealandicus (Broun, 1880) , Paracymus pygmaeus (W.J. Macleay, 1871) .

Figures

FIGURE 5. Right male proclaw of Antiporus kalbarriensis sp. n. (scale bar 0.1 mm).

FIGURE 6. Map showing the two collecting localities of A. kalbarriensis sp. n. (black dots) in Western Australia.

FIGURES 1 – 4. Habitus of 1) Antiporus bakewellii (male), 2) A. kalbarriensis sp. n. (male) (scale bar 1 mm). Lateral (a) and ventral views (b) of median lobes of aedeagi of 3) A. bakewellii and 4) A. kalbarriensis sp. n. (scale bar 0.4 mm). Photos: L. Hendrich.

FIGURES 7 – 8. Habitat of A. kalbarriensis sp. n., 7) View over the Murchison River from Hawk´s Head Lookout; 8) Backwater pool at Murchison River near Ross Graham Lookout (Loc. 19 / 183). Photos: L. Hendrich.