Melobasis myallae, Carter

Levey, Brian, 2023, A revision of the Australian species of the genus Melobasis Laporte & Gory 1837 (Coleoptera: Buprestidae), Part 3 (Revision of the azureipennis, cupricollis, iridicolor and melanura species groups), Zootaxa 5302 (1), pp. 1-100 : 33-36

M. myallae Carter

(Figs 11, 27, 53)

Melobasis myallae Carter 1932:102 ; 1939:300; Bellamy 2002:157; 2008:1327.

Type locality: New South Wales , Bogan River [Most probably between Nyngan and Dandaloo. See Armstrong, J.W.T. (1953) A Definition of the Place Label “ Bogan R., N.S. Wales, The Australian Entomologist Oct. 1953 Vol. 1 Supp. 1.] .

Type specimens examined. Holotype ♀ ( AMSA) Bogan. R. N.S. Wales J. Armstrong / On Myall / HOLOTYPE / HOLOTYPE / Melobasis myallae Cart. Paratype ♀ ( ANIC) Bogan. R. N.S. Wales J. Armstrong / Taken on Myall / PARATYPE / PARATYPE / Melobasis myallae Cart. Id. By H.J. Carter / Paratype Melobasis myallae Carter comp. with orig. desc. B. Levey det. 1974.

Diagnosis. Only ♀ known. General diagnosis: length 9.75–10.31 mm; head in upper third greenish bronze with a violet reflection, lower two-thirds brown bronze with a greenish reflection at centre in lower third; pronotum greenish bronze with a strong violet reflection becoming violet blue near the lateral margin; elytra brown to blackish bronze, humeral callosities and basal margin sometimes with coppery reflections, apices and lateral margins narrowly violet blue; underside brown bronze with extensive violet and reddish violet reflections, particularly on the legs and abdominal ventrites; underside glabrous at centre, moderately densely clothed with moderately long silvery pubescence laterally.

Head ( Fig. 27 ): very densely punctate with small round punctures, the spaces between the punctures shiny, densely clothed with moderately long silvery pubescence which partly conceals the punctation; clypeal excision a narrow moderately deep U shaped notch between broad bisinuate lobes, clypeal peaks slightly developed, clypeal angles not developed; vertex flat, about one half width of head across eyes when viewed from above; eyes strongly convex.

Antenna: segments 3–10 expanded, segment 3 subtriangularly expanded, 4 subquadrate, segments 5–10 with expansion quadrate, very slightly petiolate at base.

Pronotum: 1.41–1.57× as wide at base as long in midline; anterior margin moderately strongly bisinuate with a broad moderately developed median lobe, with a well developed entire beaded margin; posterior margin weakly bisinuate; widest near midlength; weakly almost rectilinearly diverging from basal angle to widest point, before weakly almost rectilinearly converging from widest point to apical angles; basal angles right-angled; about as wide at base as elytra at base; lateral carina sharp well defined, slightly curved, about two-thirds complete; punctation in central half very dense to contiguous, consisting of small transversely ellipsoidal punctures, mostly arranged in regular transverse series, with traces of an impuncate median linein anterior half; punctation in lateral half, slightly larger, very dense to contiguous, the punctures becoming progressively less ellipsoidal, mostly ovate to round near the lateral margin; spaces between punctures weakly microreticulate; glabrous except for sparse moderately long silvery setae near the anterior angle and next to the lateral carina.

Scutellum: about as long as wide, shield shaped, about one-fourteenth width of elytra at base; moderately strongly microreticulate.

Elytra: 2.35–2.39× as long as wide at base; basal margin weakly bisinuate, very weakly widening from base over the humeral callosities thence almost parallel sided to midlength, before narrowing to the broadly rounded apices; lateral margins in apical half and apices serrate, with acute serrations; sutural margins slightly raised in apical half; almost uniformly densely to very densely punctate with small round to slightly ellipsoidal punctures in inner half, punctures becoming larger slightly transverse ellipsoidal in lateral half, where they partly coalesce to form transverse series; without seriate punctation or costae, but with a slightly costate interval next to the poorly defined subsutural depression; moderately strongly microreticulate between the punctures.

Hypomeron: very contiguously punctate with medium sized, shallow, ovate punctures, the bottoms of which are moderately strongly microreticulate, moderately densely clothed with adpressed moderately long silvery pubescence.

Prosternum: with a narrow bead at the anterior margin; the anterior margin at about the same level as the area behind; glabrous at centre, moderately densely clothed with moderately long silvery pubescence in lateral two-thirds; prosternal process strongly widening distally, about as wide as long at its widest point, densely to very densely punctate with small round punctures, almost glabrous.

Mesanepisternum: contiguously punctate with moderately large very shallow round and variably shaped setae bearing punctures in anterior half, very densely punctate with variably shaped and very small punctures in posterior half.

Central part of metaventrite and inner third of metacoxae, sparsely punctate with small round punctures, glabrous; punctation of lateral parts composed of very dense to contiguous lunate punctures, moderately densely clothed with moderately long silvery pubescence; abdominal ventrites glabrous to very sparsely clothed with mostly short silvery pubescence at centre, moderately densely clothed with moderately long silvery pubescence laterally; punctation composed of very small elongate lunate punctures at centre, laterally composed of much larger very dense to contiguous lunate punctures.

Apical ventrite (Fig 53): lunate punctures very dense at centre, in lateral two-thirds forming grooves parallel to the lateral margin; carinate in midline near the apical excision; excision narrow, moderately deep, U shaped, with a moderately developed flange and moderately long, slightly divergent lateral spines.

Fore tibia: slightly curved, with a slightly developed setal brush in apical seventh on the anterior face.

Mid tibia: slightly curved.

Ovipositor: not examined.

Comments. This species is most similar to M. incisa sp. n. and M. adusta sp.n. From M. adusta sp. n. it differs in the much more regular punctation of the elytra, without costate intervals. From M. incisa sp. n. the main differences are that the apical ventrite in M. incisa is not carinate in the midline close to the excision and the lunate punctures on the lateral parts of apical ventrite are less coalescent, the grooves less strongly developed close to the lateral margin; the form of the frontoclypeal excision which is deeper in M. incisa and the punctation of the prosternal process which is slightly denser in M. incisa . Only the discovery of males of M. myallae will clarify its status.

Bionomics. Adults collected on Myall ( Acacia pendula ). Larval host unknown.

Figures

FIGURES 27–32. 27–30 head from front: 27. M. myallae Carter (holotype ♀); 28. M. adusta sp. n. (J paratype 12 km N. Paynes Find. BLC); 29. M. adusta sp. n. (J Wurarga, W.A. ANIC); 30. M. adusta sp. n. (J Carnac Island, W.A. SAMA); 31–32 prosternal process: 31. M. incongruens sp. n. (holotype ♀); 32. M. costata Macleay (J Marmor, Q. BLC). Scale bars = 1.0 mm.