Microdacne styxia Skelley, Leschen & Liu, 2021

Skelley, Paul E., Leschen, Richard A. B. & Liu, Zhenhua, 2021, New Australian Erotylinae with notes on Dacnini (Coleoptera: Cucujoidea Erotylidae), Zootaxa 4948 (3), pp. 363-380 : 374-375

Microdacne styxia Skelley, Leschen & Liu , new species

Figures 26–28 , 32

Diagnosis. A member of Microdance as defined above, distinguished from the other species by the short sublateral sulcus present only near posterior angle of the pronotum and being from the Styx River State Forest, near Wollomombi, New South Wales.

Description. Length 2.8 mm; width 1.5 mm. Body, antennal club and legs black; antennal base, palpi and tarsi tan ( Fig. 26–28 ); elytra with band not touching suture that leaves a small brown spot at base of humerus, band on apical third apparently absent.

Head broad, dorsal interocular distance = 8× ocular width in dorsal view; surface with distinct setose punctures, sparse and fine medially, becoming denser and coarser laterally and anteriorly; clypeus with anterior margin narrow; gena and lateral gula with scattered coarse punctures slightly smaller than facets; mentum transverse, width = 3.7× length; anterior margin of plate nearly straight. Antennomeres shortly, sparsely setose; antennomere 11 subcircular, obliquely truncate apically.

Pronotum strongly convex, transverse, width = 1.3× length (holotype suspected to be female), widest near middle; punctures of central disc same diameter as on head, half diameter of facet, reduced laterally; anterior margin deeply emarginate next to anterior angle, strongly projecting medially; lateral margin with fine marginal bead; strong, deep sublateral sulcus separated from margin by distance = diameter of eye, sulcus present on posterior 1/5 of pronotum, sulcus basally connected to groove of posterior marginal bead ( Fig. 32 ); posterior marginal bead strong medially, with few coarse punctures in groove either side of mid-line, stopping at base of sulcus, not present near posterior angles.

Elytra strongly convex, short, length = width; base nearly straight; strial punctures weak on disc, absent laterally; minute punctures with short setae widely scattered over surface.

Prosternal process laterally arcuate, narrowing posteriorly, rounded apically, medial knob bluntly rounded. Mesoventrite lateral tubercles widely set, distance between them = 2.5× basal width, central concavity evenly rounded. Abdominal ventrite 1 with coxal lines weakly extending onto ventrite.

Genitalia not dissected; normally curved protibial base indicates specimen is female.

Material examined. The unique female holotype of Microdacne styxia ( Figs. 26–28 ) label data: “[white paper, printed] 30.36S to 30.44S & / 152.05E to 152.10E / Styx R. SF. approx. SE / Wollomombi, NSW / Aug. 1993 - Mar. 1994 / D. S. Chandler ” // “[white paper, printed] Berlesate ANIC 1839 / 870–990m / rotten wood / leaf litter” // “[orange paper with camera symbol] ANIC / Image” // “[red paper, printed] HOLOTYPE ♀ / Microdacne / styxia / Skelley, Leschen, Liu” ( ANIC) .

Etymology. The species name is for the Styx River, the type locality, with the suffix “-ia” meaning “of the Styx”.

Figures

FIGURES 23–28. Microdacne spp.: 23–25) Microdacne nardia sp. nov., holotype, habitus; 23) dorsal view; 24) ventral view; 25) lateral view; 26–28) Microdacne styxia sp. nov., holotype, habitus; 26) dorsal view; 27) ventral view; 28) lateral view. Scale bar = 1.0 mm.

FIGURES 29–32. Microdacne spp., holotypes, anterolateral dorsal oblique view of head and pronotum: 29) M. gloriousa; 30) M. lamingtonia; 31) M. nardia; 32) M. styxia. Scale bar = 1.0 mm.