Gymnochthebius inlineatus, Perkins, 2005

Perkins, Philip D., 2005, A revision of the water beetle genus Gymnochthebius Orchymont (Coleoptera: Hydraenidae) for Australia and Papua New Guinea, Zootaxa 1024 (1), pp. 1-161 : 1-161

Gymnochthebius inlineatus new species

(Figures 62, 63, 74)

Type Material. Holotype (male): Australia: Western Australia: Millstream, creek nr. Deep Reach , 21° 35' S, 117° 4' E, 8 November 1970, E. B. Britton. Deposited in the ANIC . Paratypes (12): Australia: Northern Territory: Finke River at Glen Helen Gorge, West Macdonnells NP, flowing river, large pools, with bulrushes, sandy bottom, algal growth, 23° 41' S, 132° 40' E, 10 March 1995, T. Weir (1 ANIC) ; Hugh River , 12.5 km SSE of Paisley Bluff, flowing river, deep pool, grass at edges, sandy bottom, 23° 49' S, 133° 22' E, 7 March 1995, T. Weir (2 ANIC) ; Palm Valley , 24° 4' S, 132° 45' E, 1–30 April 1968, C. Watts (2 SAMA) ; Simpson Gap, West Macdonnells NP, large pools in flowing creek (temporary) with grass at edge, 20° 40' S, 133° 43' E, 6 March 1995, T. Weir (4 ANIC) ; Western Australia: Fortescue River 12k S Newman , 23° 28' S, 119° 44' E, 27 May 2001, C. H. S. Watts (1 SAMA) ; Lyndon R. Bridge , 23° 36' S, 113° 51' E, 13 August 1975, K. & E. Carnaby (2 ANIC) . Representative specimens to be deposited in MCZ and NPC .

Differential Diagnosis. A very distinctive species (Fig. 62), separated from all others in the genus by the combination of the non­serial elytral punctation, each puncture with a short, slightly flattened and widened seta, the convex body form, the fringe of long setae on the elytral margin, and the abdominal hydrofuge covering ventrites 1–2 and basolaterally on 3. The male genitalia show some slight resemblance to those of G. squamifer and G. minipunctus , both of which are very different in habitus (Figs. 56, 66).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.52/ 0.71; head 0.33/0.44; pronotum 0.37/0.59; elytra 0.96/0.71. Form moderately ovate, moderately convex. Color dark brown, dorsum weakly shining, with distinctive whitish or yel­ lowish setae.

Head with dorsum clothed in distinctive decumbent setae; frons sparsely punctate; interocular foveae deep; interocular tuberculi distinct; basomedial fovea narrowly confluent with interocular foveae. Frontoclypeal suture deeply impressed, bisinuate. Clypeus midlength about 0.5 apical width, moderately coarsely punctate. Labroclypeal suture straight in dorsal view, evenly arcuate in anterior view. Labrum width about three times length, anterior margin with very small apicomedian tooth.

Pronotum lateral hyaline border well developed, origin at base of lateral depression, arcuate to posterior angles, very narrow around posterior margin; anterior margin of pronotum arcuate between lateral depressions; each lateral depression with posterior angle slightly acute, lateral margin weakly arcuate, densely clothed in setae which overlap one another; lateral fossulae deep, terminating anteriorly in pit; pronotal disc moderately convex, very effacedly microreticulate and moderately densely punctate, each puncture with a distinctive recumbent whitish seta which contrasts with dark cuticle; median groove moderately deep and wide, constricted in midlength, extending nearly to margins, tapering at ends; anterior foveae well developed; posterior foveae oblique, linear impressions 1/2 as long as and about as wide as median groove; posterolateral angles lacking impressions.

Elytra quite convex on disc; punctures random on disc, becoming serial laterally and behind posterior declivity; each puncture microreticulate and with a distinctive short flat recumbent seta; summit of declivity slightly behind midlength; sutural margin slightly raised; elytral explanate margin narrow, with fringe of short arcuate setae.

Metasternal glabrous area length equal width, oval, shining, convex. Abdominal sternites 1–2 and basolateral part of 3 with hydrofuge pubescence.

Aedeagus (Fig. 63): Length of main­piece 0.23 mm, length to tip of parameres 0.24 mm; lobes of moderate length, barbed subapically; dorsal notch deeper and wider than ventral notch; paramere setae short.

Females are similar to males in form of the elytral explanate margin; the anterior margin of the labrum is arcuate.

Etymology. Named in reference to the non­serial elytral punctation.

Distribution. Currently known from western Western Australia and southern Northern Territory (Fig. 74).