Melobasis acutula, Levey, 2012

Levey, Brian, 2012, 3464, Zootaxa 3464, pp. 1-107 : 26-27

M. acutula sp. n.

(Figs. 108, 171, 217)

Type locality: Western Australia, Wurarga, Marloo sheep station (28°24'S 116°29'E) .

Type specimens examined. Holotype ♂ ( ZMHB) W. Australien, Marloo Station , Wurarga, 1938, A. Goerling, S.G. Marloo Stn ., Paratypes as follows: 1♂ ( ZMHB), same data as Holotype ; 2♀ ( ANIC) Wurarga, W.A., 1931–1941, A. Goerling .

Diagnosis. General diagnosis: length 12.5–15.3 mm.; head and pronotum brownish- or greenish-bronze with reddish-violet or violet reflections; elytra deep purple, with the following coppery or golden markings: a sutural vitta in the basal quarter; a humeral vitta of about the same length which does not reach the basal margin of the elytra; a sinuate median fascia strongly narrowed or almost broken into two maculae at the middle; a roughly obovate pre-apical macula; underside brownish-bronze, sometimes with reddish-purple reflections; lateral parts of underside moderately densely clothed with fairly long silvery pubescence.

Head: upper third of vertex densely punctured with fairly large round to ovate punctures; remainder of head very densely punctured with ovate punctures which largely coalesce to form linear series orientated dorso-ventrally on the rest of the vertex and the frontoclypeus; moderately densely clothed with moderately long silvery pubescence; unpunctured areas shiny except on the frontoclypeus which is sometimes weakly microreticulate; clypeal excision rather shallow, U- to V-shaped, with an unpunctured shiny to weakly microreticulate border; clypeal peaks almost right angled; vertex flat, about two-thirds width of head across eyes when viewed from above; eyes weakly to moderately convex.

Antenna: serrate from segment 4–10, the segments becoming progressively smaller and slightly less elongate, the expanded part of each segment quadrate in ♂, more or less triangular in ♀.

Pronotum: 1.53–1.69 times as wide at base as long in midline; anterior margin scarcely produced at the centre in ♂, with a moderately developed broad median lobe in ♀; posterior margin bisinuate; almost as wide at posterior angles as at mid-length; lateral margins almost parallel for a short distance in front of posterior angles before very weakly diverging to mid-length, then moderately strongly curvilinearly converging to the anterior angles; slightly narrower at base than elytra at base; lateral carina slightly sinuate, about half complete; punctation in ♂ sparse in central fifth, consisting of small round puncture, in ♀ consisting of pin-prick punctures, punctation becoming progressively larger and denser towards the lateral margin; with or without traces of an unpunctured midline in posterior half; shiny; moderately densely clothed with fairly long silvery pubescence in lateral half.

Scutellum: very slightly transverse, slightly wider distally, the lateral margins straight or weakly curved, about one-eleventh to one-thirteenth width of elytra at base.

Elytra: 2.33–2.46 times as long as wide at the base; basal margin weakly bisinuate; very slightly widening from base over the humeral callosities; thence almost parallel sided to the mid-length, before narrowing to the rounded apices; lateral margins from just beyond mid-length and apices with moderately coarse acute serrations; sutural margin slightly raised in apical half; rather uniformly punctured, but with traces of two or three costate intervals in the inner two-thirds; internal of the first costate interval, sparsely punctured with very small round punctures; external to the first costate interval the punctures become larger and dense, to very dense near the lateral margin, where they become ovate and form short transverse series; moderately strongly microreticulate.

Proepisternum: contiguously punctured with moderately large, shallow, ovate punctures, partly obscured by dense long silvery pubescence.

Prosternum: with a well defined bead at the anterior margin, the anterior margin at almost the same level as the area behind; prosternal process moderately strongly widening distally, sparsely punctured with small punctures, with a line of slightly larger punctures near the lateral margin; glabrous.

Mesoepisternum: very densely punctured, with moderately large, shallow, ovate punctures; partly obscured by long silvery pubescence.

Apical sternite: with the lunate punctures coalescent, their rims forming weak ridges more or less parallel to the lateral margin; ♂ excision shallow almost three times as wide as deep (very similar to that of M. flexa sp. n. ( Fig. 207)); ♀ excision fairly deep, not much wider than deep ( Fig. 217); lateral spines scarcely developed; distal margin of flange straight.

Tarsal claws: slightly widened at base, but without a basal tooth.

Aedeagus ( Fig. 171): median lobe with an acute apex.

Ovipositor: not examined.

Comments: This species is morphologically similar to specimens lacking the dorso-ventral flexure of the elytra that I excluded from the type series of M. flexa . It is possible that M. acutula is just a colour variant with reddish-copper elytral markings, not blue. However this type of colour variation is not seen in other species of the formosa species-group, and the configuration of the elytral markings is somewhat different, the humeral vitta not reaching the basal margin of the elytra as it does in the above mentioned specimens and in the type series of M. flexa . M. acutula shares with M. flexa the acute apex to the median lobe of the aedeagus.

Etymology. The name comes from the acute apex of the median lobe of the aedeagus.

Bionomics. Unknown.