Melobasis planithorax, Levey, 2018

Levey, Brian, 2018, A revision of the Australian species of the genus Melobasis Laporte & Gory 1837 (Coleoptera: Buprestidae), Part 2 (Revision of the nervosa species group), Zootaxa 4528 (1), pp. 1-79 : 36-37

M. planithorax sp. n.

(Figs 19, 71–72, 126, 159, 208)

Type locality: Western Australia, McDermid Rock .

Type specimens examined. Holotype ♂ (WAMA) McDermid Rock, WA, Oct. 25 1986, Acacia lvs. M. Powell/ Mc Dermid Rock, W. Australia, 25 Oct 1986, M.R. Golding Collection, on Acacia leaves / HOLOTYPE Melobasis planithorax sp. n. B. Levey 2017. Paratypes as follows: 1♂ (MPC) same data as holotype.

Diagnosis. (male only, female unknown). General diagnosis: length 13.1–13.9 mm; upperside and underside brown bronze, except for lower two-thirds of head which has a greenish or coppery reflection, and suture and 1 st costa which are violet; underside laterally densely clothed with moderately long silvery pubescence.

Head (Fig. 159): upper quarter of head densely punctate, with strong, small, round and ovate punctures, punctures on lower three-quarters of head contiguous, mostly coalescing to form elongate series; densely clothed with long silvery pubescence; clypeal excision moderately deep, almost V-shaped; clypeal border broad, impunctate; clypeal peaks right angled or obtuse angled, with a poorly defined clypeal angle; vertex flat, about half width of head across eyes when viewed from above; eyes very strongly convex.

Antenna: ♂ triangularly serrate from segment 4–10, the segments subequal, about twice as long as wide, slightly petiolate at base; segment 3 subcylindrical, slightly widening distally, about 2–3 × as long as wide at its widest point.

Pronotum: 1.52–1.55 × as wide at base as long in midline; anterior margin strongly bisinuate, with a well developed, moderately broad median lobe, with a complete narrow beaded margin; posterior margin very weakly biarcuate; widest at basal angles; lateral margins very slightly sinuate just anterior to basal angles, thence very slightly, almost rectilinearly, or very weakly curvilinearly converging to anterior angles; basal angles right angled; as wide at base as elytra at base; disc slightly flattened; lateral carina slightly sinuate, about two-thirds complete; punctation in central-fifth sparse, consisting of small, shallow, weak, round and pin-prick punctures; punctation in lateral four-fifths dense, consisting of larger, stronger, slightly ovate punctures; without an impunctate median line; moderately densely clothed, with moderately long, silvery pubescence, in lateral half, glabrous in central-half.

Scutellum: almost quadrate to slightly transverse, about one-twelfth to one-fifteenth width of elytra at base.

Elytra 2.61–2.62 × as long as wide at base; basal margin very weakly biangulate; slightly widening from the base over the humeral callosities, thence parallel sided to a little beyond mid-length, before narrowing to the subacute apices; lateral margins in apical half and apices with moderately coarse, acute, serrations; sutural margins slightly raised in apical third, becoming slightly costate in central-third; each elytron with traces of four approximately equidistant costae: 1 st extending from base almost to apex; 2 nd costa extending from base to apical fifth, very narrow, much narrower than 1 st; 3 rd costa extending from the humeral callosity to apical third; 4 th costa from humeral callosity almost to apex; 3 rd and 4 th costae very narrow, scarcely defined; the costae and raised sutural margin very sparsely punctate, with very small, weak, and pin-prick punctures; subsutural depression densely punctate, with small, round, to slightly transversely elliptical punctures; punctation of rest of elytra consisting of very slightly larger, transversely elliptical punctures, forming short transverse series lateral to the 3 rd costa; moderately strongly microreticulate.

Hypomeron: contiguously punctate with shallow round punctures, partly obscured by dense long silvery pubescence.

Prosternum: with a broad bead at the anterior margin; the anterior margin at the same level as the area behind; prosternal process slightly widening distally, sparsely punctate with small, weak, round punctures.

Mesanepisternum: contiguously punctate, with small, mostly round, shallow punctures, partly obscured by dense long silvery pubescence.

Central part of metaventrite, inner part of metacoxa, central part of abdominal ventrites glabrous, moderately densely punctate with small lunate punctures, lateral parts of these structures very densely to contiguously punctate, with small lunate punctures, densely clothed with long silvery pubescence, which partly obscures the punctation.

Apical ventrite ♂ (Fig. 126): lunate punctures coalescing to form grooves parallel to the lateral margin, partly obscured by the pubescence; excision broad, W shaped, with a curved flange at the centre; lateral spines well developed, parallel (Fig. 126).

Fore tibia ♂ (Fig. 208): slightly curved, with a large posteriorly facing tooth at apex, and a well developed setal brush on the anterior face at the apex.

Mid tibia: ♂ slightly curved without teeth.

Aedeagus (Figs 71–72): parameres strongly constricted behind the apical setae bearing part; apical setae bearing parts slightly widened, apical half weakly chitinised, with numerous, fairly long, slightly curved, spine-like setae, in addition to the usual long fine setae; median lobe narrowly produced at tip.

Comments. The aedeagus of this species is very similar to that of M. costifera , but externally it is easily distinguished from that species by the scarcely enlarged tooth at the apex of the elytra, the much larger posteriorly facing tooth at the apex of the fore tibia, and the differently shaped flange of the apical ventrite in the ♂. Externally it is most similar to M. angustecostata subacuta but differs in the more parallel sided pronotum, which is flattened on the disc, the much larger posteriorly facing tooth at the apex of the fore tibia, and the differently shaped flange of the apical ventrite, and the form of the aedeagus.

Etymology. The name comes from the flattening of the disc of the pronotum in this species.

Bionomics. Adult collected in late October on Acacia leaves . Larval host unknown.