Gymnanthelius tunicus, Perkins, Philip D., 2004

Perkins, Philip D., 2004, A revision of the Australian endemic water beetle genus Gymnanthelius Perkins (Coleoptera: Hydraenidae), Zootaxa 585, pp. 1-39 : 20-22

Gymnanthelius tunicus new species

( Figures 8 , 16 , 24 )

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; deposited in the ANIC. Paratypes (246): Same data as holotype (131 ANIC, NPC). New South Wales, Alpine Ck., nr. Kiandra, 35° 54', 148° 36', 27 January 1966, E. Britton — (1 ANIC); Victoria, 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) — (113 ANIC); 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) — (1 ANIC). Representative specimens deposited in AMSA, BMNH, CMNH, FMNH, MCZ, MVMA, QMBA, QPIM, SAMA, TMSA, UQIC, USNM, and WAMP.

Diagnosis. Recognized by the scabrous elytral disc with the surface very uneven between large random punctures, the random or only subserial "series" 5 and 6, and the comparatively large size, ca. 2.08 mm long. Refer to diagnoses of G. maxipunctus and G. hieroglyphicus for comparison.

Description. Holotype 2.08 x 0.94; head length 0.41, width 0.48; pronotum midlength 0.48, maximum width 0.63 just behind anterior angles; elytra length 1.26, maximum width 0.94. Form moderately ovate, transversely quite convex. Dorsum black with faint coppery metallic reflections, very strongly punctate.

Eyes moderately large, in dorsal aspect 9 convex facets in longest series. Clypeus and frons mcr., dull, except shining anterior margin of clypeus, coarsely moderately densely punctate, punctures on clypeus largest, c. 1.5x eye facet, interstices c. 1– 2 x puncture diameter; each puncture on disc with short very indistinct recumbent seta; anterolateral angles acuminate. Frons interocular foveae deeply impressed, longitudinal; not confluent with basomedial longitudinal weak carina behind median relief. Ocelli very indistinct. Labrum in male anteriorly produced in two weakly reflexed lobes separated by U­shaped median emargination, each lobe ca. 2x length of last maxillary palpomere, setae distinct on disc, laterally forming narrow fringe.

Pronotum anterior margin slightly emarginate before anterior angles, hyaline border well developed. Lateral depression 3 times as wide anteriorly as posteriorly, side weakly bisinuate, emarginate before tooth­like posterior angle. Lateral hyaline border well developed, anterior extreme nearly attaining anterior angles, continuing in rather uniform width along sides, widest just behind lateral depression, in dorsal aspect margin oblique to midline, arcuate. Lateral fossulae deep, mcr., inner margin abrupt, outer margin obsolete; without anterior or posterior pit. Disc transversely convex, gradually widening from anterior to about middle, then sides converging but only very slightly so to base; densely coarsely punctate, punctures c. 1– 2 x eye facet, interstices dull, effacedly mcr., c. 0.5– 3 x puncture diameter. Median groove mcr., slightly constricted in middle, slightly wider in anterior than posterior 0.5, each end tapering and not attaining respective hyaline border. Anterior foveae shallow but distinct, punctate, each slightly wider than median groove at same level, separated from median groove by c. 1x fovea width, margins ill­defined. Posterior foveae absent.

Elytra widest at middle, sides regularly arcuate; explanate margin distinctly wider before midlength, narrower than metatibia, declivous, surface flat or only slightly transversely convex, origin at anterolateral angles, becoming obsolete near posterior 0.2, without discernable setae. Apices conjointly narrowly rounded. Transversely very convex, lateral and posterior declivity abrupt. Elytral punctures very large, c. 2– 3 x size of largest pronotal punctures, serial to subserial on declivous sides, on disc very dense, random, subscabrous. Each puncture bearing short subdecumbent seta.

Metasternal glabrous area subtriangular, length equal width, widest near base. Ventrites 1–4 with hydrofuge pubescence.

Aedeagus: Length 0.41 mm.; mainpiece relatively wide, apex relatively blunt; distal part of internal tube wide, cupuliform; parameres with distal pair of setae relatively short and thick ( Fig. 16 ).

Etymology. Latin, garment, skin; named in reference to the thick dorsal cuticle; even the tarsal claws are thickened.

Distribution. Currently known from New South Wales and Victoria ( Fig. 24 ).

Figures

FIGURE 8. Gymnanthelius tunicus holotype. Dorsal and lateral habitus.

FIGURES 14 – 17. Gymnanthelius aedeagi. — 14. G. hieroglyphicus (specimen from NSW, Khancoban). — 15. G. po rc h i (holotype). — 16. G. tu nic u s (holotype). — 17. G. maxipunctus (holotype).

FIGURES 22 – 25. Gymnanthelius geographical distributions. — 22. G. opacicollis. — 23. G. hieroglyphicus. — 24. G. t u n i c u s. — 25. G. maxipunctus.