Melobasis robusta, Carter

Levey, Brian, 2012, 3464, Zootaxa 3464, pp. 1-107 : 74-75

M. robusta Carter

( Figs. 141, 187)

Melobasis robusta Carter 1923:77 , 85; 1929:285; Obenberger 1930:434; Bellamy 2002:162; 2008:1332 Type locality: Western Australia, Kellerberrin.

Type specimens examined. Lectotype ♂ selected here ( MVMA) Kellerberrin W. Australia J. Clark [crossed out]/ H.J. Carter coll. P. 20.4.22/ Type ♂ H.J.C. / Type ♂ / my lectotype label . Paralectotypes as follows. 1♂ ( MVMA) Kellerberrin W. Australia Crawshaw / Melobasis robusta Carter Id. by H.J. Carter / Type ♂ H.J.C./ Type ♂ / my paralectotype label; 1♂ ( SAMA) Kellerberrin W. Australia W. Crawshaw / Co-Type ♂ H.J.C./ Melobasis robusta Carter Id. by H.J. Carter/ my paralectotype label; 1♂ ( ANIC) Kellerberrin W. Australia Crawshaw / Co-Type ♂ H.J.C.; 2♂ ( UQA) Cunderdin W.A. R. Illidge / Co-Type H.J.C. M. robusta .

Other specimens examined. Western Australia: Albany; Bonnie Rock; Lake Grace; Marloo Station, Wurarga; Southern Cross; 13 Km S. of Yellowdine.

Specimens examined from ANIC, CLBC, GBC, IRSNB, MVMA, NMWC, SAMA, UQA, WAMA.

Diagnosis. General diagnosis: length 13.4–20.6 mm; entirely dark brown-bronze; underside sparsely to very sparsely clothed with short silvery pubescence.

Head: very densely punctured with strong round and ovate punctures which coalesce to form linear series on the lower two-thirds of the vertex; frontoclypeus sometimes strongly depressed medially; glabrous or with sparse short inconspicuous silvery pubescence on the frontoclypeus; unpunctured areas shiny or weakly microsculptured; clypeal excision shallow, U or V-shaped, with a microreticulate border only developed medially; clypeal peaks obtuse or rounded; vertex slightly convex, about three-fifths width of head across the eyes when viewed from above; eyes weakly to moderately convex.

Antenna: ♂ serrate from segment 3–10, segment three slightly enlarged and triangular, segments 4–10 oblong, becoming progressively smaller; ♀ serrate from segment 4–10, segment 4 and sometimes 5 triangular, expanded part of other segments oblong.

Pronotum: 1.44–1.53 times as wide at base as long in midline; anterior margin strongly bisinuate, with a strongly produced median lobe; anterior beaded margin narrow, but well defined; posterior margin bisinuate; widest at mid-length; lateral margins parallel sided for a short distant in front of posterior angles, before weakly diverging to mid-length, then strongly curvilinearly converging to the anterior angles; as wide at base as elytra at base; lateral carina slightly sinuate, about half to three-quarters complete; punctation moderately dense to dense medially, consisting of moderately large round or transversely ovate punctures, punctures becoming progressively larger and very dense laterally; without an unpunctured midline, however, sometimes with a poorly delineated sparsely punctured area on either side of the midline in the anterior half; shiny to weakly microsculptured; glabrous.

Scutellum: quadrate to slightly transverse oblong, shiny, about one-tenth to one-fourteenth width of elytra at base.

Elytra: 2.00–2.36 times as long as wide at base; basal margin weakly to moderately strongly bisinuate; slightly widening from base over the humeral callosities, thence parallel sided to slightly beyond mid-length, before narrowing to the rounded apices; lateral margins in apical half and apices with small weak serrations, sometimes only very slightly developed even at the apices; sutural margins slightly raised in apical third; subsutural depression moderately densely punctured with small round punctures; lateral to the subsutural depression the punctures become progressively larger and denser, becoming contiguous towards the lateral margin; sometimes with some longitudinal seriation of the punctation close to the subsutural depression, but without costate interstriae; weakly microreticulate.

Proepisternum: moderately densely to densely punctured with large shallow ovate punctures, sparsely clothed with inconspicuous very short silvery pubescence.

Prosternum: with a narrow bead at the anterior margin, the anterior margin at almost the same level as the area behind; prosternal process slightly widening distally, sparsely punctured with small round punctures, with a line of larger contiguous punctures close to the lateral margin for its entire length; glabrous or with very sparse short silvery pubescence.

Mesoepisternum: shiny, with very sparse, mostly pin-prick punctures.

Apical sternite: with moderately large lunate punctures, sometimes partly coalescent near the base and lateral margin; excision shallow crescent-shaped, about two to three times as wide as deep, the lateral spines slightly developed in ♂, scarcely developed in ♀.

Mid tibia: ♂ slightly curved, slightly swollen, with a long setae-filled depression on the ventral face, ♀ straight, without a setae-filled depression.

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

Aedeagus ( Fig. 187): apical setae-bearing part of parameres with long fine setae only.

Comments: This very robust, brown-bronze, sparsely pubescent species is unlikely to be mistaken for any other species. In the field small specimens might be mistaken for large specimens of M. uniformis Carter or brownbronze specimens of M. cuprifera (Laporte & Gory) . The short sparse translucent silvery pubescence of the underside of this species will distinguish it from the former two species (pubescence of underside denser, longer and opaque white).

Bionomics. Adults collected between October and January. Larval hosts unknown.