Gymnanthelius opacicollis Perkins, 2004, new species
Creators: name: Perkins, Philip D.
Publisher: name: Zenodo
Year: 2004
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydraenidae
Gymnanthelius
Gymnanthelius opacicollis

description: Gymnanthelius opacicollis new species
(Figures 6, 11, 22)
Type Material. Holotype (male): Australia, Victoria, Traralgon Ck., 0.2 km N. “Hogg Bridge”, 5.0 km NNW. Balook, 38.24S 146.32E, 170 m; ex silty sand on small sand­bank in creek (low water) backwater in wet sclerophyll forest, 13.i.1999, N. Porch (NP10); deposited in the ANIC. Paratypes (436) (all collected in Victoria by N. Porch, unless otherwise noted; deposited in ANIC and other institutions): Same data as holotype (119). 1 km N. Possum Hollow, W. br. Tarwin River, 4.6 km SSW. Allambee, ex shaded silty mud at edge of small 'creek' at pasture­wet sclerophyll forest boundary, elev. 240 m, 38° 18' S, 146° 1' E, 14 January 1999, N. Porch (NP 19) — (29); Elizabeth Ck., 1.2 km S. Childers, very abundant in sandy mud and wet litter (80cm by 20cm) along edge of small forest creek in wet sclerophyll forest (Eucalyptus regnans), elev. 195 m, 38° 19' S, 146° 6' E, 28 October 1998, N.Porch (NP 9) — (22); Franklin River at South Gippsland Highway, on and in shaded silty mud at edge of small 'creek' in pasture, elev. 10 m, 38° 39' S, 146° 18' E, 13 January 1999, N. Porch (NP 14) — (1); Latrobe River at Piedmont, gravel at edge of river at pasture/forest boundary, elev. 255 m, 37° 53' S, 145° 54' E, 1 January 2003, N. Porch & N. Krause (NP 54) — (7); Lerderderg River, 6.8 km N. Bacchus Marsh;, wet gravel and cobbles at edge of small river; dry sclerophyll forest, elev. 135 m, 37° 37' S, 144° 25' E, 20 September 1999, N. Porch (64) — (1); Little Morwell River, 3.8 km NNE. Mirboo North, sandy mud and litter accummulation at edge of small creek; dry/moist riaprian sclerophyll forest, elev. 165 m, 38° 22' S, 146° 10' E, 3 October 1999, N. Porch (NP 45) — (7); same locality, elev. 165 m, 38° 22' S, 146° 10' E, 24 February 2001, N. Porch & Latrobe Valley Field Naturalists (LVFN) (NP 10) — (37); Little Morwell River, at Ricardo Road, Darlimurla, litter and mud at edge of small creek in dry sclerophyll forest, elev. 250 m, 38° 22' S, 146° 12' E, 9 April 2000, N. Porch (NP 49) — (1); Otway Range, Hopetoun Falls, in spray zone below, handpicked from spray wetted expanses of rock within 10–20m of waterfall, elev. 240 m, 38° 40' S, 143° 34' E, 27 September 2001, N. Porch (76) — (1); Possum Hollow falls, W. br. Tarwin River, 5.6 km SSW. Allambee, along edge of stream on wet algae covered rocks, under leaves and active in open. Wet sclerophyll forest (Eucalyptus regnans), elev. 240 m, 38° 19' S, 146° 1' E, 14 January 1999, N. Porch (NP 15) — (57); Possum Hollow falls, W. br. Tarwin River, 5.6 km SSW. Allambee, ex wet films along margin of rills flowing over smooth mudstone. Wet sclerophyll forest (Eucalyptus regnans), elev. 240 m, 38° 19' S, 146° 1' E, 14 January 1999, N. Porch (NP 16) — (13); Possum Hollow falls, W. br. Tarwin River, 5.6 km SSW. Allambee, ex sandy mud between cobbles at edge of riffle 0.1 km below waterfall; wet sclerophyll forest (Eucalyptus regnans), elev. 240 m, 38° 19' S, 146° 1' E, 14 January 1999, N. Porch (NP 18) — (48); Turtons Creek, d/s Turtons Creek Falls, 2.9 km SSE. Tarwin East, ex wet films along margin of rills flowing over smooth mudstone. Wet sclerophyll forest/pine plantation­pasture, elev. 155 m, 38° 32' S, 146° 15' E, 5 February 1999, N. Porch (NP 29) — (2); Turtons Creek Falls, 3.5 km SSE. Tarwin East, ex mud in small, shallow bowl about 40 cm by 20 cm; wet sclerophyll forest — pasture, elev. 175 m, 38° 33' S, 146° 15' E, 5 February 1999, N. Porch (NP 32) — (91); Turtons Creek Falls, 3.5 km SSE. Tarwin East, on/in mud, sand and amongst rocks at base of small falls of Turtonís Creek. Wet sclerophyll forest — pasture, elev. 175 m, 38° 33' S, 146° 15' E, 5 February 1999, N. Porch (NP 30) — (52).
Other material examined: Allambee, 6.2 km SSW. of, falls on the West Branch of Tarwin River, seeps and splash­zone of steep rocky cascading 'falls' in wet sclerophyll forest beside road, elev. 220 m, 38° 19' S, 146° 1' E, 9 April 2000, N. Porch (NP 73) — (130); Morwell River, 6.1 km SSE. Boolarra on Morwell River Road (Apex Park), willow roots and sandy mud/gravelly mud at edge of small river; under weeping willows, elev. 115 m, 38° 25' S, 146° 18' E, 29 November 1999, N. Porch (NP 38) — (38); Otway Range, 0.2km below Hopetoun Falls;, litter and gravelly mud at edge of stream in closed wet forest, elev. 230 m, 38° 40' S, 143° 34' E, 27 September 2001, N. Porch (NP 78) — (10).). Representative specimens deposited in AMSA, BMNH, CMNH, FMNH, MCZ, MVMA, QMBA, QPIM, SAMA, TMSA, UQIC, USNM, and WAMP.
Diagnosis. A very distinctive species, recognized by the head and especially pronotum very dull, microreticulate, markedly contrasting with the shining elytral reliefs, the large elytral punctures, the resulting irregular margins of the elytral intervals, the brownish coppery dorsum with faint metallic reflections, the entirely hydrofuge pubescent metasternum, and the comparatively large size, length ca. 1.93 mm.
Description. Holotype 1.93 x 0.94; head length 0.44, width 0.56; pronotum midlength 0.46, maximum width 0.67 just behind anterior angles; elytra length 1.22, maximum width 0.94. Form moderately ovate, moderately convex. Dorsum brownish coppery, pronotum with faint metallic reflections, legs brown.
Clypeus and frons mcr., dull, except shining anterior margin of clypeus; clypeus very finely sparsely punctate, pubescence very indistinct; interocular foveae deep, small, each much smaller than distance separating them, each a deep pit; area between interocular foveae flat; ocelli very distinct. Frontoclypeal suture shallowly impressed, arcuate. Clypeus length:width as 8:15, anterior angles each minute acuminate point; basally punctures much larger than those of frons, becoming finer apically. Labroclypeal suture straight in dorsal view, evenly arcuate in anterior view. Labrum length:width as 7:15, anteriorly produced in two lobes separated by U­shaped median emargination, lobes slightly reflexed; each lobe slightly longer than last maxillary palpomere, setae distinct on disc, laterally forming distinct fringe. Maxillary palpomere 3 about 2x length of 4.
Pronotum anterior margin almost evenly arcuate from side to side, only weakly emarginate near anterior angles; anterior hyaline border well developed; each lateral depression four times as wide anteriorly as posteriorly, side weakly emarginate before tooth­like posterior angle. Lateral hyaline border well developed, anterior extreme nearly attaining anterior angles, continuing in raher uniform width along sides, widest just behind lateral depression, in dorsal aspect margin oblique to midline, nearly straight except slightly indented opposite posterior extreme of lateral depression. Lateral fossulae only moderately deep, inner margin gradual, outer margin obsolete; without anterior or posterior pit. Disc transversely weakly convex, gradually widening from anterior to slightly beyond midlength, then sides converging slightly to base; dull, mcr., densely, moderately coarsely punctate. Median groove wide, widest near anterior extreme, then gradually tapering to posterior, each end tapering to point and nearly attaining respective hyaline border. Anterior foveae very shallow, margins very indistinct. Posterior foveae absent.
Elytra shining, widest at middle, sides regularly arcuate, disc transversely quite convex, posterior declivity rather abrupt, summit slightly behind midlength. Disc with five rows of moderate sized punctures in deep striae between suture and prominent humeral umbo, punctures encroaching on intervals, each puncture with minute recumbent seta; series 2 and 3 terminating beyond summit of posterior declivity, 1 and 4 attaining apices. Intervals transversely rounded, 1– 2 x puncture width, surface shining but with finely impressed lines and micropunctures. Explanate margin in male narrower than metatibia, declivous, surface flat or only slightly transversely convex, origin just behind anterolateral angles, becoming obsolete near posterior 0.2, with short, very sparse, indistinct recumbent setae. Apices in male conjointly rounded.
Metasternum entirely hydrofuge pubescent, very slightly depressed in middle. Ventrites 1–4 with hydrofuge pubescence.
Aedeagus: Length 0.41 mm.; mainpiece almost parallel sided in distal 0.5, apex nearly symmetrical, wedge­shaped; parameres with distal pair of setae relatively long (Fig. 11).
Etymology. Named in reference to the pronotal microsculpture, which gives the appearance of being covered with an opaque film.
Distribution. Currently known from Victoria (Fig. 22).
description: Published as part of Perkins, Philip D., 2004, A revision of the Australian endemic water beetle genus Gymnanthelius Perkins (Coleoptera: Hydraenidae), pp. 1-39 in Zootaxa 585 on pages 16-18, DOI: 10.5281/zenodo.157433