Melobasis sordida, Blackburn

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 : 40-42

M. sordida Blackburn

(Figs 29, 81–82, 133–134, 164, 179)

M. obscura Saunders 1876:157 (preoccupied: M. obscura Macleay 1872 ); Kerremans 1885:137; 1892:107; 1903:158; Carter 1923:81; 1929:286; Obenberger 1930:435; Bellamy 2002:164; 2008:1333. Type locality: South Australia, Adelaide.

M. sordida Blackburn 1887:238 (nom. nov. M. obscura Saunders 1876 ); 1890:146; 1892:36; Kerremans 1892:107; 1903:158; Carter 1923:81; 1929:286; Obenberger 1930:435; Bellamy 2002:164; 2008:1333. Stat. rev. (not syn. of M. simplex (Germar)) .

M. viridisterna Carter 1939:299 ; Bellamy 2002:166; Bellamy 2008:1336. Syn. nov. Type locality: New South Wales, Cooma.

Type specimens examined. M. obscura Saunders Holotype ♀ (BMNH) Adel./ Saunders 74.18/ obscura E.S./ HOLOTYPE Melobasis obscura Saunders B. Levey det. 1972.

M. viridisterna Carter Lectotype ♂ (ANIC) [here selected] Cooma NSW, W. Duboulay 26-12-36 / Holotype ♂ / M. viridisterna Carter. Paralectotype ♀ (ANIC) [mounted on same card as Lectotype] Allotype ♀. [Carter in his original description mentions that there are four specimens from Cooma and two from Kiata, Victoria, and that the holotype was presented to AMSA. The above specimens are the only ones I have found and I have therefore selected the Lectotype from these specimens.]

Other specimens examined. Western Australia: Beverley; Bind Bindi, 25 km N.; Boonya; Juranda Rock Hole, 106 km S. of Balladonia; Lake Cronin; Lake Cronin, 30 km S.; Norseman, 40 km S.; Northam; Spencers Brook. South Australia: Adelaide; Ardrossan; Clarendon; Cleve Hills; Cowell, 34 miles N.; Gawler; Moonta; Dutton; MacDonald Reservoir, Monarto South; Mt Hall, Eyre Peninsula; Murray Bridge; Parra Wirra National Park; Streaky Bay; Quorn; Quorn, 1 km S.E.; Rockleigh; Tumby Bay; Yorktown. Victoria: Birchip; Cowwarr; Grampians; Kiata; Rainbow, 15 km W.S.W.; Wyperfield Parish. New South Wales: Bulga; Bungendore; Burrinjuck; Captains Flat; Gunnedah; Hill End; Mt. Hope, 2 km E.S.E.; Nepean Gorge, near Mulgoa; Tinda Creek, Putty Rd.; Queanbeyan; Singleton; Waterfall. A.C.T.: Black Mt., Canberra; Blundells. Queensland: Edungalba; Gogango Range, 33 km E. of Duaringa; Milmerran; Mt Archer, Rockhampton. Specimens in AMSA, ANIC, ASC, BLC, BMNH, IRSNB, MPC, MVMA, NMPC, QMA, SAMA, SGCB, TMSHC WADA, WAMA.

Diagnosis. General diagnosis: length 7.8–11.6 mm; slightly sexually dichromatic: ♂ upperside largely olive green or dull purple, with lateral quarter of pronotum, elytra at the basal angle and head green; prosternum, prosternal process, mesanepisternum, mesosternum, central part of metaventrite, basal abdominal ventrite and legs mostly green, rest of underside reddish violet; ♀ upperside entirely olive green, dull purple or blackish bronze; underside entirely olive green, dull reddish violet, or deep violet, except sometimes anterior face of fore femora green.

Head (Fig. 164): contiguously punctate with small round strong punctures in ♂, very densely to almost contiguously punctate in ♀, the punctures slightly weaker; moderately densely clothed with moderately long silvery pubescence, which does not obscure the punctation; rims of the punctures shiny to weakly microreticulate; clypeal excision shallow, U-shaped, the excision rather narrow, with a narrow poorly defined partly punctate border; clypeal peaks acute, clypeal angles usually well defined; vertex flat, slightly less than half width of head across eyes when viewed from above; eyes very strongly convex.

Antenna: slightly sexually dimorphic; ♂ segments 3–10 weakly triangularly expanded; ♀ basal segments more strongly triangular; antennae and segments more elongate in ♂, than in ♀.

Pronotum: 1.48–1.59× as wide at base as long in midline; anterior margin strongly bisinuate, usually with a slightly developed, broad median lobe, sometimes only slightly produced, and truncated; with a narrow but well defined beaded margin; posterior margin very weakly bisinuate; widest at basal third; lateral margins parallel sided for a very short distance from basal angles, before diverging to widest point, thence converging to apical angles; basal angles acute; as wide as, or very slightly narrower at base, than elytra at base; lateral carina almost straight or slightly curved, about two-thirds to four-fifths complete; punctation in central half very dense, consisting of transversely oval to strongly elliptical punctures, arranged in slightly sinuate transverse rows; punctures in lateral half becoming progressively more round towards the lateral margin; with no trace of an impunctate median line; glabrous, or with very short inconspicuous pubescence near the anterior angle.

Scutellum: shield shaped, about one-fifteenth to one-fourteenth width of elytra at base.

Elytra 2.26–2.47× as long as wide at base; basal margin very weakly bisinuate; slightly widening from the base over the humeral callosities, thence slightly widening to mid-length, before narrowing to the broadly rounded apices; lateral margins in apical half and apices with coarse acute serrations; sutural margins slightly raised in apical two-thirds; each elytron with traces of two or three scarcely raised, approximately equidistant costae; punctation fairly uniform, the punctures becoming progressively slightly larger, and more transverse towards the lateral margin, mostly arranged in transverse rows; weakly microreticulate.

Hypomeron: very densely to contiguously punctate, with large, very shallow, mostly ovate punctures, with sparse short silvery pubescence.

Prosternum: with a broad bead at the anterior margin; the anterior margin at the same level as the area behind; prosternal process moderately strongly widening distally, moderately densely, to densely punctate, with fairly strong round to ovate punctures, glabrous.

Mesanepisternum (Fig. 179): weakly to strongly microreticulate, with shallow round to ovate setae bearing punctures, confined to the anterior half.

Central part of metaventrite, inner part of metacoxa, central part of abdominal ventrites glabrous or sparsely pubescent, more sparsely and weakly punctate than lateral parts of these structures, which are very densely punctate with lunate punctures, with sparse moderately long silvery pubescence.

Apical ventrite (Figs 133–134): lunate punctures coalescing near the lateral margin and forming grooves; excision in ♂ broad, W shaped, with a narrow, almost triangular, sometimes truncated flange, at the centre, with long, well developed, parallel lateral spines (Fig. 133); ♀ narrower, U-shaped, with a moderately broad flange for its entire width, the lateral spines well developed, parallel to slightly divergent (Fig. 134).

Fore tibia: ♂ moderately strongly curved, with a very small triangular tooth at apex, and a slightly developed setal brush on the anterior face at apex; ♀ tibia weakly curved, tooth absent, and setal brush poorly developed.

Mid tibia: ♂ strongly curved without teeth or a depression along the ventral face; ♀ weakly curved.

Aedeagus (Figs 81–82): parameres moderately strongly constricted before the apical setae bearing part; apical setae bearing parts scarcely widened, about one third the total length of the parameres, apical half weakly chitinised, with numerous, fairly long, slightly curved, spine-like setae, in addition to the usual long fine setae; median lobe truncate at the tip.

Ovipositor: not examined.

Comments. This species is most easily distinguished from the other small to medium sized species of the group, by the very dense punctation of the central area of the pronotum, where the punctures even in the midline are transverse oval or elliptical, and arranged in transverse series, and in having the elytral costae scarcely developed. M. rubromarginata has the pronotal punctation almost as dense, but the elytral costae are much better developed, and the elytra are more elongate (2.56–2.79 × as long as wide at base in M. rubromarginata , 2.26–2.47× in M. sordida ). The bicoloured underside of the male is also diagnostic. The aedeagus is most similar to that of M. rubromarginata , but the apex of the median lobe is different (subacute in M. rubromarginata , truncate in M. sordida ).

Bionomics. Adults have been collected from September to February, most records in December and January. Adults have been mostly collected from leaves of Acacia spp. ( Fabaceae ), including A. jennerae and A. calamifolia , with single records from Leptospermum phylicoides (Myrtaceae) , Callitris preissii (Cupressaceae) , Xanthorrhoea leaves, and flowers of Dilwynia sp. ( Fabaceae ). Larval host A. microbotrya .