Melobasis igniceps, Saunders

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 : 26-28

M. igniceps Saunders

(Figs 24, 73–74, 122–123, 160)

Melobasis igniceps Saunders 1876:156 ; Kerremans 1885:136; Masters 1886:73; Kerremans 1892:105; 1903:160; Carter 1929:285; Obenberger 1930:431; Bellamy 2002:154; Bellamy 2008:1323.

Type locality: North West Australia .

Type specimens examined. Holotype ♂ (BMNH) M. igniceps Saund. N.W. Aust. / igniceps E.S./ Saunders 74:18.

Two manuscript names have been found attached to specimens of this species, M. cupricauda Carter and M. tamminensis Brown.

Other specimens examined: W. Australia: Bejoording; Coorow, 10 km S.; Duggin; Esperance; Geraldton; Glenfield District, 5–6 miles N.N.E. of Geraldton; Marchagee track, 7.4 km W. of Midlands Rd.; Marchagee track,

8.4 km W. of Midlands Rd.; Marchagee track, 15.5 km W. of Midlands Rd.; Marloo Station, Wurarga; Moora, 11km N.; Perth; Mullewa, 65 km W. of; Tammin; Watning [Wattening?];Wicherina Dam, Eradu; Witton Well Rd., 22km S. of Moora/ Dandaragan; Yalgoo, 48 miles W. Specimens in AMSA, ANIC, BMNH, CLBC, GHNC, IRSNB, MVMA, NMWC, TMSHC, UQA, WAMA, ZMHB. S. Australia: Gawler [labelled as Gowlerstown] (NMPC); Moolooloo (SAMA); Quorn (SAMA).

This species shows considerable variation and the specimens from S. Australia might be representatives of a different undescribed subspecies or species. These specimens have the 2 nd and 3 rd elytral costae much better developed than those from W. Australia and other slight differences. Unfortunately the specimens I have seen are all female, so I refrain from description until more specimens becomes available.

Diagnosis. General diagnosis: length 12.7–15.3 mm; head in ♂ reddish copper to reddish purple, in ♀ greenish or brown bronze; pronotum, elytra, and underside, brown or greenish bronze, lateral margins of elytra in apical half and apices, reddish violet or lilac.

Head (Fig. 160): upper half of vertex densely punctate with strong, small, round and ovate punctures, punctures on lower half of head contiguous, often coalescing to form elongate series, with obvious shiny ridges between the punctures; densely clothed with long silvery pubescence; clypeal excision shallow U- or V-shaped; clypeal border narrow to broad, impunctate, sometimes microreticulate; clypeal peaks right angled or acute, usually with a well defined clypeal angle; vertex flat, about half width of head across eyes when viewed from above in ♂, slightly wider in ♀; eyes very strongly convex, slightly more convex in ♂.

Antenna: very slightly sexually dimorphic; triangularly serrate from segment 4–10, the segments becoming progressively shorter especially in the ♀, petiolate at base; segment 3 subcylindrical, slightly widening distally, about 2–3 × as long as wide at its widest point.

Pronotum: 1.31–1.49 × 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 weakly bisinuate; widest just in front of mid-length; lateral margins slightly divergent from basal angles to widest point, before weakly converging to apical angles; basal angles slightly acute or right angled; as wide as, or very slightly narrower at base than elytra at base; lateral carina slightly sinuate, about half to two-thirds complete; punctation in central-quarter sparse, consisting of small, shallow, weak, round, and pin-prick punctures, often with a narrow almost complete impunctate median line; punctation lateral to central-quarter consisting of slightly larger, denser slightly elliptical punctures, becoming very dense to contiguous in the lateral half, where the punctures are round or ovate; moderately densely clothed, with moderately long, silvery pubescence in lateral half, glabrous in centralhalf.

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

Elytra 2.40–2.58 × as long as wide at base; basal margin weakly bisinuate to biangulate; slightly widening from the base over the humeral callosities, thence slightly widening to a little beyond mid-length, before narrowing to the rounded or sub-acute apices; lateral margins in apical half and apices with rather weak, acute, serrations; sutural margins slightly raised in apical third, becoming slightly costate nearer the base; each elytron with one well defined costa, and traces of one or two others; the 1 st costa and raised sutural margin very sparsely punctate with pin-prick punctures; subsutural depression densely punctate, with small, round to slightly transversely elliptical punctures; punctation of rest of elytra very dense to contiguous, consisting of larger, transversely elliptical punctures, mostly coalescing to form transverse series lateral to the traces of the 2 nd costa; weakly to moderately strongly microreticulate.

Hypomeron: contiguously punctate, with small shallow 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, to moderately strongly widening distally, sparsely punctate, with small, weak, round, and pin-prick punctures, glabrous, or with sparse pubescence near the lateral margin.

Mesanepisternum: contiguously punctate, with small, mostly round, shallow, punctures, partly obscured by dense long silvery pubescence, except for outer fifth to third, which is impunctate.

Central part of metaventrite, inner part of metacoxa, central part of abdominal ventrites glabrous, or with sparse long silvery pubescence, moderately densely punctate with very 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 (Figs 122–123): lunate punctures coalescing to form grooves parallel to the lateral margin, partly obscured by the pubescence; excision in ♂ broad, W shaped, with a broad curved to truncate flange at the centre; lateral spines well developed, slightly divergent (Fig. 122); ♀ narrow U-shaped, the lateral spines well developed, slightly divergent (Fig. 123).

Fore tibia: ♂ strongly curved, with a small triangular tooth at apex and a series of slightly smaller teeth along the ventral face; with a well developed setal brush on the anterior face at the apex; ♀ tibia less curved, teeth absent and setal brush less developed.

Mid tibia: ♂ strongly curved, with a small triangular tooth at apex, and a series of slightly smaller teeth along the ventral face; ♀ almost straight, without teeth.

Aedeagus (Figs 73–74): parameres slightly constricted behind the apical setae bearing part; apical setae bearing part broad, weakly chitinised, with numerous, fairly long, slightly curved, spine-like setae, in addition to the usual long fine setae; median lobe with a slightly spatulate tip.

Ovipositor: not examined.

Comments. This species is externally most similar to M. a. angustecostata ssp. n., but is easily distinguished by the very different aedeagus. Externally, the usually less developed 2 nd and 3 rd elytral costae, and the reddish violet or lilac apices and lateral margins of elytra in apical half, appear to be reliable external distinguishing characters.

Bionomics. Adults have been collected from September to November on leaves of thin leaf Acacia spp. including A. signata . Also collected on A. blakeleyi (Hanlon pers. comm.). Larval hosts unknown.