Melyronyxa monteithi Gimmel and Leschen, 2023

Gimmel, Matthew L. & Leschen, Richard A. B., 2023, Melyronyxa, a New Genus of Lophocateridae from Australia (Coleoptera: Cleroidea), The Coleopterists Bulletin 77 (1), pp. 49-57 : 52-55

Melyronyxa monteithi Gimmel and Leschen , new species zoobank.org/ urn:lsid:zoobank.org:act:04244F71-45D9-4E5E-B2FD-12258738D4FD ( Figs. 1–3 , 6, 8 , 9, 11, 12 , 14 )

Type Material. Holotype. Point-mounted male, with the following data labels:“SEQ:23°55′Sx 151°11′E \ Mt Beecher, 0.5km NW \ 27Sep 1999. 20m \ GB Monteith.pyrethrum \ -tree trunks. 7771”, and “ HOLOTYPE \ Melyronyxa monteithi \ Gimmel & Leschen [red label]” (deposited in QM) . Paratypes (3). “ AUSTRALIA: QLD: Sarabah NP ,

120 m, 28°03′S 153°07′E, 21 Nov 2007, leg. G. Monteith ”, and “ PARATYPE Melyronyxa monteithi Gimmel & Leschen ” (3♂♂ [including voucher G0067 with DNA extracted, disarticulated with missing meso- and metaventrite, deposited in ANIC]; ANIC, QM) .

Diagnosis. This species may be distinguished from M. pubescens by the smaller average body size (2.1–2.5 mm in M. monteithi , 2.1–2.8 mm in M. pubescens ), antennomere 9 short, no longer than antennomere 8 ( Fig. 6 ) (antennomere 9 much longer than 8 in M. pubescens , Fig. 7 ), transversely oval glandular area on the gulamentum of the male ( Fig. 8 ) inconspicuous, without raised rim, and with small setal tuft (glandular area with raised rim and with a distinct tuft of long setae in M. pubescens ), dorsal erect setae longer ( Fig. 3 ), about as long as length of antennal club (dorsal erect setae shorter, about as long as antennal club width in M. pubescens ), setae dark brown (setae yellowish brown in M. pubescens ), cuticle dark brown ( Fig. 1 ) (cuticle medium brown in M. pubescens , Fig. 4 ), median lobe of aedeagus ( Fig. 9 ) long, narrow (median lobe short, wide in M. pubescens , Fig. 10 ), and tegmen ( Figs. 11, 12 ) with long median strut widened at base, and with short knob-like posterior projections (tegmen with short basal strut not widened at base, and with long sausage-like posterior projections in M. pubescens , Fig. 13 ).

Description. Total length 2.1–2.5 mm. Uniformly medium to dark reddish-brown dorsally ( Fig. 1 ) and ventrally, appendages somewhat lighter. Dorsal setae ( Fig. 3 ) dark brown, about as long as antennal club length.

Head ( Fig. 2 ) about 0.7× as wide as pronotum at greatest width. Antenna ( Fig. 6 ) short, total length distinctly less than head width; with sparse long setae in whorls on each antennomere; antennomere 1 enlarged, rounded; antennomere 2 smaller than 1; antennomere 3 as long as 1 but much narrower; antennomere 4 shorter than 3; antennomeres 4–6 each shorter and wider than previous; antennomeres 7–9 forming abrupt, somewhat flattened, symmetrical club, 7 and 8 each shining and glabrous with truncate apical surface covered in sensory setae, 8 slightly shorter than 7; antennomere 9 shorttriangular and rounded apically, about as long as and two-thirds as wide as antennomere 8, with sensory field covering most of apical half. Transverse oval structure on anterior portion of gulamentum in males ( Fig. 8 ) a glandular field without a raised rim and with group of setae, setae shorter than width of glandular area.

Dorsal surface of head ( Fig. 2 ) and pronotum with large, flat, dense, contiguous polygonal punctation, giving the appearance of coarse reticulations; each puncture with long, erect seta originating from center. Pronotum transverse, about 0.55 times as long as wide, almost as wide as elytral bases together; 0.25–0.29 times length of elytra; rounded laterally but widest in posterior half with sides converging anteriorly, anterior angles weak, posterior angles obtuse; lateral edges with smooth serrations most prominent in posterior half.

Elytra together about 1.6–1.7 times as long as wide; elytral surface shining, without microsculpture, sutural stria absent, disc with large window punctures separated by less than diameter of a puncture, each seta on disc of elytron originating from the rim of a window puncture, with only one seta per puncture; lateral margins with large, shallow crenulations for most of length, becoming more pronounced and almost serrate in apical one-fourth, with one long setae originating from each crenulation, also with short, sparse, recumbent setae present along margin; margin evenly explanate for entire length, explanate portion without window punctures; elytral epipleural disc with sparse, scattered, short, erect setae.

Male genitalia with basal strut of tegmen ( Figs. 11, 12 ) nearly as long as sheath portion of tegmen, extending anteriorly beyond sheath portion, flared anteriorly,formingatail-flukeshape( Fig.11 );postero-dorsal paired projections of tegmen short, knob-like, setose apically and ventrally, apical setae about as long as projections, ventral setae shorter. Median lobe in morphologically lateral view ( Fig. 9 ) narrow, abruptly curved about 90° at midlength; apex round- ed and with distinct ventral tooth, subapical serrations also present ventrally.

Etymology. This species is named after Geoff Monteith (Queensland Museum, Brisbane, Australia),

collector of the type series. It is a noun in the genitive case.

Distribution. Known from two localities in lowland eastern Queensland, Australia ( Fig. 14 ).

Biology. One specimen was collected from tree trunks using pyrethrum.

Figures

Figs. 1–3. Melyronyxa monteithi, new species, habitus. 1) Dorsal aspect; 2) Frontal aspect; 3) Left lateral aspect.

Figs. 6–8. Characters of the head of Melyronyxa, new genus. Antenna: 6) M. monteithi, new species; 7) M. pubescens. Head capsule, ventral aspect: 8) M. monteithi, new species (arrow indicates gular pit).

Figs. 9–13. Male genitalia of Melyronyxa, new genus. Median lobe, lateral (apex at right): 9) M. monteithi, new species; 10) M. pubescens. Tegmen (apex up): 11) M. monteithi, new species, ventral; 12) Same, lateral; 13) M. pubescens, lateral. Scale bars = 100 μm.

Fig. 14. Distribution map of the two species of Melyronyxa, new genus. Star = M. monteithi, new species; circle = M. pubescens. The New South Wales and Victoria records are approximate.

Figs. 4–5. Melyronyxa pubescens, syntype. 4) Dorsal aspect; 5) Labels. Photos by Keita Matsumoto, © Natural History Museum, London.