Melobasis costifera, Thomson

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 : 16-17

M. costifera Thomson

(Figs 17, 67–68, 118–119, 157, 183)

Melobasis costifera Thomson 1879:16 ; Blackburn 1890:146; Kerremans 1892:105; 1903:158; Carter 1923:82; 1929:284; Obenberger 1930:429; Bellamy 2002:148; 2008:1318. Type locality: Western Australia, Swan River.

Melobasis costata Saunders 1876:155 (preocc. M. costata Macleay 1872 ); Kerremans 1885:136 (Melabasis); Masters 1886:74; Blackburn 1890:146; Kerremans 1892:105; 1903:158; Carter 1923:82; 1929:284 (syn. of M. costifera Thomson ); 1931:108 (syn. of M. interstitialis Blackburn ); Obenberger 1930:429; Bellamy 2002:148; 2008:1318. Type locality: Western Australia, Swan River.

Melobasis saundersi Masters 1886:74 (nom. nov. for Melobasis costata Saunders 1876 ); Blackburn 1890:146; Kerremans 1892:105; 1903:158; Carter 1921:2; 1923:82; 1929:284; Obenberger 1930:429; Bellamy 2002:148; 2008:1318.

Type specimens examined. Melobasis costata Saunders. Lectotype, here designated, ♀ (BMNH), M. costata Saund. / Swan River/ M. costata / Saunders 74.18/ Lectotype Melobasis costata Saunders B. Levey det. 2012. The original description gives a size range, which indicates that Saunders had more than one specimen before him when he described the species.

Other specimens examined. Western Australia: Albany; Beverley; Busselton; Cottesloe; Dongara; Dryandra; Eradu; Esperance; Fremantle; Geraldton; Kwinana; Jervis Bay; Lake Grace; Monument Hill; Narngulu; Naval Base; Nedlands; Perth; Rottnest Island; Swan River; Waneroo; Wembley South Australia: Parkside; Quorn; Robe. Tasmania: Scott’s Lagoon, Flinders Island. Specimens in AMSA, ANIC, BLC, BMNH, CLBC, GHNC, UQA, IRSNB, MVMA, QMA, SAMA, TMSHC, WADA, WAMA.

Diagnosis. General diagnosis: length 11.7–15.8 mm; entirely yellow to blackish bronze, the elytral costae usually darker than the rest of the elytra; underside laterally densely clothed with long silvery pubescence, most of prosternum, prosternal process, mesosternum, and central parts of metaventrite and abdominal ventrites glabrous or very sparsely pubescent.

Head (Fig. 157): contiguously punctate with small strong punctures which are arranged in dorso-ventrally orientated linear series over most of the vertex and frontoclypeus; sometimes with traces of a median carina in the lower half of the frons; densely (♀) to very densely clothed (♂) with long silvery pubescence which partly obscures the punctation; ridges between the punctures shiny; clypeal excision shallow U-shaped, with a fairly broad complete impunctate microreticulate border; clypeal peaks right angled, sometimes with a well defined clypeal angle; vertex flat, slightly more than half width of head across eyes when viewed from above; eyes very strongly convex.

Antenna: not sexually dimorphic; weakly triangularly serrate from segment 4–10, the segments becoming slightly progressively shorter; segment 3 subcylindrical, slightly widening distally, about 2–3 × as long as wide at its widest point.

Pronotum: 1.55–1.69 × as wide at base as long in midline; anterior margin weakly bisinuate, with a very weakly developed broad usually truncated median lobe, with a narrow but well defined beaded margin; posterior margin very weakly biarcuate; widest at basal angles; lateral margins nearly parallel from basal angles to apical three-quarters (sometimes with a slight sinuation just anterior of the basal angles), before very weakly converging to apical angles; basal angles right angled; as wide or very slightly narrower at base than elytra at base; lateral carina slightly sinuate about half to three-quarters complete; punctation in central quarter moderately dense, consisting of small round and pin-prick punctures; punctation in lateral three-quarters dense to very dense, consisting of larger stronger round and elliptical punctures, punctures becoming contiguous and forming transverse series near the lateral carina; rarely with an impunctate median line, usually with a narrow elongate puncture or depressed line just anterior to the scutellum; sparsely to moderately densely clothed with moderately long silvery pubescence in lateral quarter.

Scutellum: almost square or shield shaped, about one-sixteenth to one-thirteenth width of elytra at base.

Elytra 2.37–3.24 × as long as wide at base; basal margin very weakly biarcuate or biangulate; very slightly widening from the base over the humeral callosities, thence parallel sided to a little beyond mid-length, before narrowing to the acute apices; lateral margins in apical third and apices with moderately coarse acute serrations, the most apical tooth much larger than the others; sutural margins slightly raised in apical half, sometimes becoming costate nearer the base, and widening in basal quarter to produce a slightly raised, elongate, slightly triangular shaped area (sutural boss); each elytron with 4 approximately equidistant costae as follows: 1st costa widest, extending from base almost to apex; 2 nd costa extending from base to apical sixth, sometimes fusing with 1st costa at apical sixth; 3 rd costa extending from near the humeral callosity to apical fifth; 4 th costa very narrow often poorly defined; the 1st costae, raised sutural margin, and sutural boss, sparsely punctate with very small weak and pinprick punctures; 2 nd and 3rd costae sparsely punctate, with small round or transverse elliptical punctures; subsutural depression densely punctate with very small round punctures; remainder of elytra densely to very densely punctate, with larger transverse elliptical punctures, which often form transverse series lateral to the 2 nd costa; shiny to weakly microreticulate.

Hypomeron: very densely to contiguously punctate, with small, partly imbricate punctures, mostly obscured by very dense long silvery pubescence.

Prosternum: with a moderately 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 and pin-prick punctures, glabrous.

Mesanepisternum (Fig. 183): densely to very densely punctate, with small round, moderately deep punctures, mostly obscured by long silvery pubescence.

Central part of metaventrite, inner part of metacoxa, central part of abdominal ventrites glabrous, more sparsely and weakly punctate than lateral parts of these structures, which are very densely to contiguously punctate, with small imbricate and lunate punctures, mostly concealed by dense long silvery pubescence.

Apical ventrite (Figs 118–119): lunate punctures partly coalescing near the lateral margin, but not forming well defined grooves; excision in ♂ broad, W shaped, with a moderately broad flange for its entire width, with long, well developed, slightly divergent lateral spines (Fig. 118); ♀ narrower, U-shaped, with a moderately broad flange for its entire width, the lateral spines well developed, slightly divergent (Fig. 119).

Fore tibia: ♂ almost straight, with a small posteriorly facing tooth at apex, and a well developed setal brush on the anterior face at the apex; ♀ tooth absent or very small.

Mid tibia: almost straight with a small tooth at the apex in both sexes.

Aedeagus (Figs 67–68): parameres strongly and abruptly constricted before 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 the tip.

Ovipositor: not examined.

Comments. The aedeagus is very similar to that of M. planithorax sp. n. (Figs 71–72), but it has a number of external differences from that species (see comments under M. planithorax ). This species is mainly known from coastal areas.

Bionomics. Adults collected mid November to early April, with most records in December and January. Adults have been collected on Acacia spp. Jacksonia sp. and Casuarina huegeliana . Larval host unknown.