Gymnochthebius lividus (Deane) 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 lividus (Deane) new combination

( Figures 9 , 10 , 82)

Ochthebius lividus Deane, 1933: 23 .

Ochthebius flavocinctus Deane 1933: 24 (holotype female deposited in MVMA, examined; type locality Victoria, Echuca). New synonymy.

Type Material. Holotype of Ochthebius lividus (female): Australia: Victoria: Echuca , [labels: "Echuca.Vic 3.1. 32 F. E.Wilson "; " Type 2276"]. Deposited in the SAMA. Holo­

type of Ochthebius flavocinctus (female): Australia: Victoria: Echuca. Deposited in the MVMA .

Differential Diagnosis. Recognized by the relatively large lateral hyaline border with its origin near the basal one­third of lateral depression, the elytral intervals twice as wide as the very weakly striate­impressed serial punctures, the non­punctate area between striae 1 and 4, resulting from shortened striae 2 and 3, the labroclypeal suture weakly bisinuate in dorsal view, and the faintly lead­like coloration of the head and pronotum. The two species which also have an anteriorly extended lateral hyaline border, G. fontinalis and G.nigriceps , differ markedly in body form, sculpture, color, and aedeagal structure ( Figs. 9 , 50, 52). G. lividus has some resemblance to G. notalis (which see).

Description. Size (length/width, mm) of the holotype of G. lividus : body (length to elytral apices) 2.00/0.96; head 0.36/0.52; pronotum 0.68/0.72; elytra 1.36/0.96. Form moderately ovate, moderately convex. Color: head black, pronotum blackish brown, faintly bluish, on disc, grading to light brown laterally, elytra and legs brown.

Frons shiny, very finely sparsely punctate, very sparsely pubescent; interocular foveae deep, L­shaped; interocular tuberculi moderately distinct; basomedial fovea narrowly confluent with interocular foveae. Frontoclypeal suture deeply impressed, bisinuate. Clypeus midlength/width 0.16/0.28, shiny, very sparsely punctate; pubescence very sparse on disc, slightly more developed laterally. Labroclypeal suture weakly bisinuate in dorsal view, evenly arcuate in anterior view. Labrum width nearly three times length, moderately densely pubescent, anterior margin arcuate, apicomedially with distinct tooth in male, slightly upturned but not emarginate in female.

Pronotum lateral hyaline border well developed, origin near basal one­third of lateral depression, in front of which margin is setose, arcuate to posterior angles, very narrow around posterior margin; anterior margin of pronotum slightly produced in midregion; lateral fossulae deep, microsculpture similar to remainder of pronotum; pronotal disc shiny, weakly convex, moderately densely punctate, most punctures separated by 2–3 times puncture diameter; median groove shallow, narrow, extending nearly to margins; anterior foveae shallow, densely punctate, slightly closer to lateral fossulae than to median groove; posterior foveae oblique, linear impressions nearly 1/2 as long as and similar in width to median groove; posterolateral angles within indistinct shallow impressions.

Elytral disc moderately convex, shiny similar to pronotum, with six rows of moderately large punctures in moderately impressed striae between suture and humeri; intervals rounded, width twice that of punctures, punctures round, separated from each other by less than puncture diameter; striae 1 (sutural) and 4 continuing to elytral apices, striae 2 and 3 ended at about apical 1/4, resulting in distinctive non­punctate area between striae 1 and 4; summit of declivity near apical one­third; explanate margin moderately wide, with sparse recumbent setae.

Prosternum with very weak midlongitudinal carina. Metasternal glabrous area large, shiny, length equal width, suboval, with extremely faint indication of midlongitudinal impression. Abdominal ventrites 1–3 and lateral, anterior areas of 4 with hydrofuge pubescence; suture between ventrites 4 and 5 more apparent than sutures separating other ventrites.

Aedeagus ( Fig. 10 ): Length of main­piece 0.36 mm, length to tip of parameres 0.41 mm; lobes moderately long, narrow, not barbed; notches U­shaped, widest apically, nearly twice width of a lobe; duct as wide as lobe, straight and nearly parallel­sided except bent at apex; apical paramere seta elongate, ca. 2x length of next longest seta.

Females have the elytral explanate margin similar to that of males; the labrum is arcuate anteriorly, and lacks a tooth; the clypeal anterior margin is bisinuate, but more weakly so than that of males.

Distribution. Widely distributed in Victoria: and currently known from a few localities in New South Wales and the Australian Capital Territory (Fig. 82).

Remarks. Deane's (1933: 23) figure of G. lividus is entirely misleading with regard to shape of the pronotum and its relief features: lateral and anterior hyaline borders are not indicated, and anterior foveae are omitted. His illustration for O. flavocinctus is even more incorrectly drawn as it lacks hyaline borders, median groove and anterior and posterior foveae; all of these features are clearly apparent on the type specimen.

Material Examined (881): Australia: Australian Capital Territory: Black Mtn. , light trap, 35° 16' S, 149° 6' E, 12 March 1968, M. S. Upton (3 ANIC) ; same locality, 35° 16' S, 149° 6' E, 27 March 1968, M. S. Upton (3 ANIC) ; Blundells Ck. 3 km E of Piccadilly Circus, flight intercept window/ trough trap, elev. 850 m, 35° 22' S, 148° 50' E, 1 January–30 March 1984, Weir, Lawrence, Johnson (1 ANIC) ; New South Wales: Albury [no date], 36° 3' S, 146° 54' E, not given (3 SAMA) ; Araluen Crk. Cmpgrnd ca. 35 km S Braidwood, at u­v light, 35° 39' S, 149° 49' E, 2–3 December 1990, Pollock & Reichert (1 NMW) ; Victoria: 12 km SE Merrijig, Howqua River , 37° 6' S, 146° 15' E, 30 November 1971, A. Neboiss (1 MVMA) ; 55 km N Cavendish, Glenelg R. at hwy 107, spring­fed billabong, Scirpus , bark, leaves at margin, 38° 3' S, 141° 0' E, 28 May 1996, R. E. Roughley (14 NMW) ; Billabong 3, Yarra Glen , 37° 39' S, 145° 22' E, 6 April 1976, A. Fletcher (6 SAMA) ; Bunyip R. at Princes Highway , amongst willow roots and on sand at edge of river under thick willow cover in pasture, elev. 40 m, 38° 5' S, 145° 45' E, 15 January 1999, N. Porch (NP 22) (1 ANIC) ; Eppalock Res., Redesdale , 37° 0' S, 144° 28' E, 27 November 1967, A. Neboiss (2 MVMA) ; Farm pond nr. Glenmaggie Res., 37° 54' S, 146° 46' E, 7 May 1977, not given (1 MVMA) ; Fryer’s Creek near mouth into Lake Eildon , 37° 11' S, 145° 53' E, 3 October 1972, P. Zwick (1 NMW) ; Goulbourn River, at Goulbourn Valley Hwy., 8.0 km SE Seymour , sandy mud at edge of large slow river, elev. 145 m, 37° 5' S, 145° 12' E, 11 August 1999, N. Porch (70) (15 ANIC) ; Holey Plains State Park, firedam on Crooke Track , fine sand and organics at the edge of a small firedam in dry sclerophyll forest, elev. 45 m, 38° 10' S, 146° 20' E, 16 April 2002, N. Porch (87) (1 ANIC) ; Jamieson River at Jamieson , river, 38° 35' S, 143° 53' E, 2 October 1972, P. Zwick (1 MCZ) ; Kiewa Valley Hwy. n. Redbank , 36° 56' S, 143° 19' E, 13 February 1998, L. Hendrich (10 NMW) ; Kororoit Creek, at Sydenham­Melton Road , organic mud and litter at edge of pool in dry creek in pasture and degraded riverine forest, elev. 110 m, 37° 41' S, 144° 38' E, 17 February 2002, N. Porch (91) (2 ANIC) ; Lake Glenmaggie at Glenmaggie bridge, sandy margins of large reservoir, elev. 75 m, 37° 53' S, 146° 44' E, 1 December 1999, N. Porch (NP 39) (38 ANIC) ; Latrobe Riv. above confluence with Thomson Riv. , 38° 9' S, 146° 34' E, 9 December 1978, not given (14 MVMA) ; Latrobe Riv., Glengarry ­ Traralgon Rd. , 38° 9' S, 146° 34' E, 9 December 1978, [collr. not given] (2 MVMA) ; Little River at Bacchus Marsh­Geelong Road , sandy gravel and muddy sand at edge of still pool of perrenial creek in riparian forest remnants, elev. 105 m, 37° 50' S, 144° 23' E, 20 October 1999, N. Porch (36) (3 ANIC) ; Loddon River at Newstead , gravel at edge of small river flowing through pasture, elev. 210 m, 37° 6' S, 144° 3' E, 27 November 1999, N. Porch (47) (66 ANIC) ; Macalister River 0.5 km below Glenmaggie weir, NMV Survey Dept. GRES Mc 22 no. 2, river, 37° 46' S, 146° 40' E, 4 December 1976, [collr. not given] (2 MVMA) ; Macalister­ Thomson River Jn, NMV Survey Dept. GRES T26 no. 1, 37° 46' S, 146° 40' E, 5 December 1976, (4 MVMA) ; Macalister­Thomson River Jn, NMV Survey Dept. GRES T26 no. 5, 37° 46' S, 146° 40' E, 7 May 1977, not given (1 MVMA) ; Macalister­Thomson River Jn, NMV Survey Dept. GRES T26 no. 6, 37° 46' S, 146° 40' E, 4 December 1976, not given (1 MVMA) ; Macalister­Thomson River Jn, NMV Survey Dept. GRES T26 no. 7, 37° 46' S, 146° 40' E, 19 February 1977, not given (1 MVMA) ; Melbourne [no date], 37° 58' S, 144° 58' E, (5 BMNH) ; Morwell River on Driffield ­ Yinnar Rd., S43, LaTrobe C. Survey , 38° 19' S, 146° 19' E, 6 December 1978, [not given] (5 MVMA) ; Narracan Ck. at Cooks Rd. , 2.3 km NW Thorpdale, in gravel at edge of gravelly riffle of small creek flowing through pasture, elev. 135 m, 38° 16' S, 146° 10' E, 4 February 1999, N. Porch (NP 28) (8 ANIC) ; Nathalia , 36° 3' S, 145° 12' E, 18 January 1961, C. Watts (1 SAMA) ; Porepunkah , Ovens R., mixed dry sclerophyll and exotic trees; at UV light near river; FMHD #87­273, elev. 300 m, 36° 42' S, 146° 55' E, 12 February 1987, A. Newton & M. Thayer (837) (5 FMNH) ; Spargo Creek, W. of, firedam nr Centre Track , clayey mud at edge of small firedam in pine forest, elev. 705 m, 37° 27' S, 144° 5' E, 17 February 2002, N. Porch (92) (3 ANIC) ; Tarago R. at Elston Rd., 1.75 km W Neerim, ex silty sand patches between waterside vegetation and wet litter along edge of riffle. Dry sclerophyll forest­pasture, elev. 170 m, 38° 28' S, 145° 56' E, 15 January 1999, N. Porch (NP 20) (109 ANIC) ; Tarago River, Bellbird Park at old Princes Highway , ex sandy mud and litter in sun along edge of slow flowing river in pasture, elev. 50 m, 38° 5' S, 145° 48' E, 15 January 1999, N. Porch (NP 21) (2 ANIC) ; Thomson River at Heyfield , wet gravel at edge of river flowing through pasture, elev. 40 m, 37° 59' S, 146° 46' E, 1 December 1999, N. Porch (55) (38 ANIC) ; Thomson River, Cowwarr­Seaton Rd, NMV Survey Dept. GRES T24 no. 3, river, 37° 41' S, 146° 13' E, 4 December 1976, not given (1 MVMA) ; Upper Yarra Dam , 37° 40' S, 145° 53' E, 28 February 1976, A. Neboiss (6 MVMA) ; Woori Yallock Ck., at Warburton Highway , ex muddy margins of undercut creek banks near water level; pasture, elev. 110 m, 37° 47' S, 145° 31' E, 23 February 1999, N. Porch (NP 35) (35 ANIC) ; Woori Yallock Creek on road to Warburton , 37° 44' S, 145° 29' E, 5 December 1972, P. Zwick (1 MCZ) ; ' Yarra Flats', Eaglemont ( Melbourne suburb), ex mud at edge of small drying 'billabong' in parklands, elev. 15 m, 37° 46' S, 145° 4' E, 26 February 1999, N. Porch (NP 37) (445 ANIC) ; Yarra River , 4.5 km SW Healesville, dry sclerophyll forest; UV blacklight along river; FMHD #87­259, elev. 80 m, 37° 41' S, 145° 29' E, 6 February 1987, A. Newton & M. Thayer (825) (4 FMNH) ; Yellow Creek, at crossing of Ovens Highway, Wangaratta , coarse sand and gravel at wet margins of gravel bar of red gum lined creek in pasture, elev. 145 m, 36° 21' S, 146° 20' E, 15 December 2001, N. Porch (88) (15 ANIC) . Representative specimens to be deposited in CMNH, FMNH, MCZ, NPC, QMBA, USNM, and WAMP .

Figures

FIGURE 9. Gymnochthebius lividus, holotype female. Dorsal and lateral habitus.

FIGURE 10. Gymnochthebius lividus. Aedeagus of specimen from Victoria: Eaglemont, Yarra Flats.