Melobasis imitator Levey 2023, sp. n.

M. imitator sp. n.

(Figs 113, 126, 140, 141, 164, 165)

Type locality: Western Australia, Cape Naturaliste.

Type specimens examined. Holotype ♁ (WAMA) Cape Naturalise [Cape Naturaliste], W.A. T.M.S. Hanlon, 25 December 2006, Acacia saligna [probably A. rostellifera T.M.S. Hanlon pers. comm.]/ HOLOTYPE Melobasis imitator sp. n. B. Levey 2012. Paratypes as follows: 1♁, 1♀ (TMSHC, BLC) same data as holotype; 1♀ (SAMA) Pt. Peron, W.A. wattle, 5.xii.54, Ex. coll. S. Barker. 1♀ (SAMA) Monument Hill, W.A. Acacia rostellifera, 7.ii.71, ♀, S. Barker. 1♀ (BLC) Mandurah, W.A. 2.i.1955, ex. coll. J.A.L. Wats [Watson), University of Westn. Australia. 3♁, 2♀ (TMSHC) 8 km S. of Leeman, W.A. 30 Dec. 2018, T.M.S. Hanlon, on Acacia rostellifera. 2♁ (TMSHC) Cape Naturaliste W.A. 19–20 Dec. 2018, T.M.S. Hanlon, on Acacia rostellifera.

Diagnosis. General diagnosis: length 7.34–7.81mm; ♁ entirely golden green; ♀ upperside and underside brownish to greenish bronze, anterior face of fore femora and tibia, and all tarsi green; head and underside laterally clothed with moderately long inconspicuous silvery pubescence.

Head (Fig. 126): contiguously punctate with small, strong, mostly round punctures in ♁, very densely punctate with slightly weaker punctures in ♀; ♁ moderately densely clothed with moderately long silvery pubescence, in ♀ sparsely clothed with moderately long silvery pubescence, mostly confined to the lower half of the head; spaces between the punctures weakly microreticulate; clypeal excision moderately deep, arcuate, with a microreticulate, impunctate border; clypeal peaks obtusely angled, or rounded; clypeal angles not developed; vertex flat, about half width of head across eyes when viewed from above; eyes strongly convex.

Antenna: segments 4–10 expanded, segment 4 with expansion quadrate (♁) or subquadrate (♀), segments 5–10 with expansion quadrate, about one and a half times to twice as long as wide in ♁, petiolate at base, in ♀ segments less elongate and less petiolate.

Pronotum: 1.54–1.64× as wide at base as long in midline; anterior margin moderately strongly bisinuate with a slightly produced, broad, median lobe, with a narrow entire beaded margin; posterior margin moderately strongly biarcuate; widest between basal third and midlength; lateral margins weakly rectilinearly diverging from basal angles to widest point, sometimes with a slight sinuation in the middle, before weakly curvilinearly converging to apical angles; basal angles slightly obtuse; as wide at base as elytra at base; lateral carina sharp, well defined, slightly curved, about two-thirds to three-quarters complete; punctation in central sixth dense, consisting of transversely oval punctures; punctation lateral to this area very dense to contiguous, consisting of transversely elliptical punctures, forming transverse series, the punctures becoming ovate and round in lateral quarter, not forming transverse series; spaces between punctures weakly to moderately strongly microreticulate; glabrous or with sparse, moderately long setae near the lateral margin at the apical angle.

Scutellum: quadrate, shield shaped, about one-twentieth width of elytra at base; microreticulate.

Elytra: 2.32–2.40× as long as wide at base; basal margin moderately strongly biangulate, slightly widening from base over the humeral callosities thence parallel sided, to very slightly widening to midlength, before narrowing to the moderately broad, slightly angulate apices; lateral margins in apical half with medium sized, acute serrations, the serrations slightly smaller between extreme apex and sutural margin; sutural margins strongly raised in apical half; each elytron with three slightly raised costate intervals, the 3rd sometimes barely visible; punctation between suture and 1st costate interval very sparse, consisting of pin prick punctures, sometimes scarcely distinguishable amongst the strong microreticulate sculpture; punctation between 1 st and 2 nd costate intervals moderately dense, consisting of small ovate punctures; punctation lateral to 2 nd costate interval dense to contiguous, consisting of transversely elliptical punctures, forming transverse series near the lateral margin; strongly to very strongly microreticulate between the punctures.

Hypomeron: contiguously punctate with very shallow, ovate punctures, the bottom of the punctures weakly microreticulate, with moderately long, adpressed, silvery pubescence.

Prosternum: with a broad bead at the anterior margin; the anterior margin at about the same level as the area behind; prosternal process moderately strongly widening distally, almost as wide as long at its widest point, sparsely punctate at centre with small round punctures, punctures towards lateral margins larger and more dense; glabrous.

Mesanepisternum: strongly microreticulate, with some scarcely distinguishable, large shallow round setae bearing punctures present.

Central part of metaventrite and inner part of metacoxa very sparsely punctate with small weak mostly pin-prick punctures, glabrous; lateral parts of metaventrite and metacoxae contiguously punctate, with fairly large shallow round and ovate punctures, sparsely clothed with moderately long silvery pubescence; abdominal ventrites glabrous at centre, with sparse, short silvery pubescence laterally; sparsely, weakly punctate, with small mostly lunate punctures in central-third, laterally with larger, coalescent, lunate punctures.

Apical ventrite (Figs 140, 141): very densely to contiguously punctate with slightly elongate, lunate punctures in lateral two-thirds, densely punctured with smaller lunate punctures in central third; excision in ♁ wide, slightly W shaped, rather deep, with a narrow flange, triangularly produced at centre; lateral spines long, slightly divergent (Fig. 140); ♀ narrower, U shaped, without a visible flange, or with a slightly developed flange, triangularly produced at centre; lateral spines long, slightly divergent (Fig. 141).

Fore tibia: ♁ slightly curved, with a setal brush at the apex on the anterior face; ♀ almost straight, with a less developed setal brush.

Mid tibia: ♁ slightly curved, without teeth on the ventral face; ♀ almost straight, without teeth.

Aedeagus (Figs 164, 165): apical setae bearing part of the parameres with very small spine-like setae, in addition to the usual long fine setae; apex of median lobe asymmetrical.

Ovipositor: about 3.0x as long as wide at widest point.

Comments. This species is not likely to be mistaken for any other species in the species group, and is the only species of the group known from S.W. Australia. Due to its similar size and colour, in the field, the female is likely to be mistaken for M. duplexicolor Levey (M. thoracica species group) which also occurs on Acacia rostellifera in S.W. Australia.

Etymology. This species is named for its superficial similarity to M. duplexicolor.

Bionomics. Adults collected on Acacia rostellifera from December to February. Larval host unknown.