Melobasis lathami, (Laporte & Gory)

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 : 32-34

M. lathami (Laporte & Gory)

(Figs 27–28, 83–85, 135–136, 169, 178)

Buprestis lathami (Laporte & Gory) 1837 :120; Saunders 1868:17; Gemminger & Harold 1869:1383; Saunders 1871:44; Masters 1886:74; Kerremans 1892:105; 1903:158; Carter 1921:2; 1923:81; 1929:285; Obenberger 1930:432; Bellamy 2002:155; 2008:1324. Type locality: Nouvelle-Hollande [ Australia].

Melobasis laeta Saunders 1876:156 ; Kerremans 1885:137; Masters 1886:73; Kerremans 1892:105; 1903:160; Carter 1923:81; 1929:285; Obenberger 1930:432; Bellamy 2002:155; 2008:1325. Type locality: Swan River.

Type specimens examined. Buprestis lathami (Laporte & Gory) Holotype ♀ ( MNHN) Type Gory / Type / Melobasis lathami Gory type [label in A. Descarpentries writing]/ Comp. with original description Holotype Melobasis lathami C. & G. B. Levey 1972.

Melobasis laeta Saunders Holotype ♀ (BMNH) Swan R/ Saunders 74:18/ HOLOTYPE ♀ Melobasis laeta Saunders B. Levey det. 1972 Comp. with desc. [Although this specimen does not bear Saunder’s determination label I believe it is the holotype of M. laeta . The locality label and the original description match this specimen. There is a specimen conspecific with M. rubromarginata which bears a handwritten label “ laeta E.S.”, with “Parry” on the underside of the label. This specimen does not agree with original description of M. laeta . I suspect that the label was either transposed from the holotype of M. laeta , or laeta E.S. was added to this label by mistake at some time in the past. The latter scenario is perhaps more likely, since Parry’s collection was apparently not at the BMNH before 1885 and Saunder’s collection came to the BMNH in 1874].

Other specimens examined. Western Australia: Albany, 15 km W.; Attadale; Balladonia; Bejoording; Beverley; Boyup Brook; Bullsbrook; Bunbury; Busselton; Cannington; Cape Naturaliste; Carlisle; Chittering; Cloverdale; Collie River; Cranbrook; Darling Range, Lane Pool C.R.; Dunsborough; Dyott Range, 30 km W.N.W. of Beverley; East Rockingham; Fitzgerald River; Furnicedale; Gingin, 20 km W.; Gnangara; Goomalling, 6 mls W.; Hamel; Jandacott; Kings Park, Perth; Lake Jandakot; Lake Muir; Mandurah; Manjimup, 40 km E.; Maylands; Midland; Mogumber; Moodiarup; Mount Yokine; Mundaring Weir, 2 mls N.; Myallup; Nedlands; Peppermint Grove, Capel; Peel Estate; Pinjarra; Salt River; Spencers Brook; Stirling Range; Stirling Range N.P., Red Gum Pass; Subiaco; Thomson’s Lake; Tone Bridge; Wandering; Waneroo; Waroona; Watning; Yanchep. Specimens in AMSA, ANIC, ASC, BCM, BLC, BMNH, CLBC, IRSNB, MVMA, QMA, SAMA, SGCB, UQA, WADA, WAMA.

Diagnosis. General diagnosis: length 6.6–13.4 mm; upperside olive–green, emerald green, or brownish bronze, often with golden reflections; elytral apices and lateral margins usually narrowly reddish purple, or reddish violet, elytral costae sometimes also similarly coloured; underside blackish bronze, dull green, or coppery, sometimes with reddish purple reflections.

Head (Fig. 169): ♂ very densely to contiguously punctate, with small, round, strong punctures; ♀ very densely to almost contiguously punctate, the punctures slightly weaker; moderately densely clothed, with moderately long silvery pubescence, which slightly obscures the punctation; rims of the punctures microreticulate in ♂, shiny to weakly microreticulate in ♀; clypeal excision very shallowly excised, with a narrow impunctate, shiny or microreticulate border; clypeal peaks right angled, without or with a slightly defined clypeal angle; vertex flat, half width of head across eyes when viewed from above; eyes very strongly convex.

Antenna: not sexually dimorphic; segment 3, and sometimes 4 triangularly expanded, segments 4 or 5 –11, with expansion almost quadrate.

Pronotum: 1.34–1.58 × as wide at base as long in midline; other characters as in M. rubromarginata but pubescence usually longer and more obvious.

Scutellum: as in M. rubromarginata .

Elytra 2.26–2.47 × as long as wide at base; other characters as in M. rubromarginata but elytral apices rounded to sub-acute.

Hypomeron: very densely to contiguously punctate, with small, shallow mostly ovate punctures, with moderately dense, moderately long, silvery pubescence.

Prosternum: with a broad bead at the anterior margin; the anterior margin slightly lower than the area behind, which is sometimes slightly tumid, and raised relative to the prosternal process; prosternal process slightly, to moderately strongly widening distally, sparsely punctate, with small, weak, round, and pin-prick punctures, sparsely pubescent or glabrous.

Mesanepisternum (fig. 178): shiny, with shallow, round setae bearing punctures, mostly concentrated in 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 moderately dense, moderately long, silvery pubescence.

Apical ventrite (Figs 135–136): lunate punctures sometimes coalescing near the lateral margin but not forming grooves; excision in ♂ broad, W shaped, flange with a narrow truncated lobe at the centre, with moderately long well developed parallel lateral spines (Fig. 135); ♀ narrower, U-shaped, with a moderately broad flange for its entire width, the lateral spines well developed, parallel, to slightly divergent (Fig. 136).

Fore tibia: ♂ strongly curved, with a series of small teeth on the ventral face, and a slightly developed setal brush on the anterior face at the apex; ♀ almost straight, and teeth absent.

Mid tibia: ♂ strongly curved, with an elongate depression along the ventral face; ♀ weakly curved and without a depression.

Aedeagus (Figs 83–85): parameres strongly, abruptly constricted before the apical setae bearing part; apical setae bearing part strongly widening apically, apical half weakly chitinised, with numerous, fairly long, slightly curved, spine-like setae, in addition to the usual long fine setae; median lobe subacute at the tip.

Ovipositor: not examined.

Comments. This species shows considerable variation in colour, elytral and pronotal proportions, and shape of the elytral apices, as well as slight differences in the form of the aedaegus (see Figs 83 & 85). The variation does not seem to be correlated with geographical distribution. It is possible that there are two sibling species involved, however I have not been able to resolve this problem with the specimens at my disposal. Molecular study is probably the best way to investigate this problem.This species is most similar to M. rubromarginata , and is most easily distinguished by the different form of the aedeagus, and the slightly less elongate elytra (2.26–2.47 × as long as wide in M. lathami ; 2.56–2.79 × as long as wide in M. rubromarginata ).

Bionomics. Adults have been collected from November to March, most records in December & January. Adults have been collected mostly on Jacksonia spp., J. furcellata , J. sternbergiana , and J. floribunda , but also one record from Gastrolobium sp. Larval host unknown.