Melobasis bilyi, Levey, 2016

Levey, Brian, 2016, Melobasis bilyi, an interesting new species of the M. pusilla species-group from Queensland, Australia (Coleoptera: Buprestidae), Acta Entomologica Musei Nationalis Pragae (suppl.) 56 (1), pp. 23-27 : 24-27

Melobasis bilyi sp. nov.

( Figs 1–5 )

Type locality. Australia, Queensland, Flying Fish Point.

Type material. HOLOTYPE: ♁, ‘Flying Fish Pt. / N.E.Q. 22.1.65. / E.C. Dahms. // To light // HOLOTYPE / Melobasis / bilyi sp. n. / B. Levey 2015’ ( QMBA) .

Description. Based on the male; female unknown.

General description ( Fig. 1 ). Length 5.2 mm (measured from anterior margin of pronotum to apex of elytra in the midline). Small subcylindrical; entirely green except for a reddish purple reflection along the lateral margins of the elytra in the apical half.

Head very densely punctured with small round to slightly polygonal strong punctures; lower half of head densely clothed with short down-curved silvery setae; upper half of head almost glabrous; surface between punctures strongly microreticulate; clypeal excision shallow U-shaped, with a complete strongly microreticulate impunctate border which is much wider at middle; clypeal peaks obtusely angled; vertex almost flat, about half the width of the head across the eyes when viewed from above; eyes moderately convex.

Antenna. Antennomeres IV–X serrate, becoming progressively slightly smaller and less elongate; expanded part of antennomere IV triangular, that of V–X nearly quadrate; XI roughly ovate, slightly shorter than X.

Pronotum ( Fig. 2 ) 1.66 times as wide at base as length at midline; anterior margin strongly bisinuate, with a strongly developed broad median lobe; posterior margin weakly bisinuate; widest at mid-length; lateral margins parallel sided in posterior quarter, then slightly widening to mid-length before weakly converging to anterior angles; as wide at base as elytra at base; lateral carina curved, about three-quarters complete; punctation dense in central half, very dense in lateral half; punctures small, strong, mostly transverse elliptical in central half, more or less round in lateral half; with a very narrow almost complete impunctate midline; strongly microreticulate between punctures; glabrous.

Scutellum slightly transverse, ovate, about one-thirteenth width of elytra at base; weakly microreticulate.

Elytra 1.82 times as long as width at base; basal margin weakly biangulate; parallel-sided over humeral callosities, then slightly constricted behind callosities before slightly widening to mid-length and narrowing to broadly rounded apices; lateral margins from mid-length to apices with fine acute serrations, those at apices slightly smaller; sutural margin moderately strongly raised in apical half; without punctured striae or costae; punctation of subsutural depression consisting of tiny round widely spaced punctures which become progressively larger, denser and more transversely elliptical laterally, becoming contiguous and forming transverse series in lateral two-thirds; strongly microreticulate.

Proepisternum very densely punctured, with large, very shallow, ovate punctures; bottom of punctures strongly microreticulate; pubescence sparse, short and inconspicuous.

Prosternum ( Fig. 3 ) with a well defined bead at anterior margin, anterior margin at the same level as area behind; prosternal process strongly widened from base, moderately densely punctured with small, strong round punctures and clothed with moderately dense long pubescence; with a line of larger partly coalescent punctures close to impunctate lateral margin.

Mesoepisternum strongly microreticulate with numerous small, inconspicuous shallow round punctures over surface.

Apical ventrite ( Fig. 5 ) with lunate punctures coalescent but not forming grooves; excision fairly shallow, about 2.5 times as wide as deep, distal margin of flange broadly arcuately produced at centre, spines short, parallel, slightly longer than depth of flange.

Mid-tibia with a small very slightly developed setae-filled depression on ventral face, tibia not obviously swollen. Tarsal claws abruptly widened at base but not cleft.

Aedeagus ( Fig. 4 ) relatively short and broad; parameres strongly widened from basal piece, widest just beyond mid-length; long sensory setae confined to basal half of narrow more transparent apical part of parameres; median lobe with apex acute, rounded at tip.

Differential diagnosis. This species keys to the M. pusilla species-group in the key to speciesgroups in LEVEY (2012). It differs from all previously described species in the group in having a well defined bead at the anterior margin of the prosternum (bead absent in other species); the prosternal process strongly widening from the base (parallel sided, almost parallel sided or weakly widening in the other species); having the excision of the apical ventrite with the flange broadly arcuately produced at the centre (flange being straight or weakly bisinuate in other species); mid-tibia in male with a small very slightly developed setae-filled depression on the ventral face (absent in other species). It does, however, share the obtuse frontoclypeal peaks and an aedeagus with the parameres strongly widening from the base, with fine sensory setae only at their apex, and the median lobe with an acute but not prolonged apex, which are seen in the other described species of the group. In the key to the M. pusilla species-group it will not key out unambiguously to any known species. The apical abdominal ventrite has contiguous lunate punctures which do not form grooves, a characteristic only found in M. inflammabilis Thomson, 1879 , from West Australia but differs from that species in the following ways: the mesoepisternum is strongly microreticulate with small round shallow punctures over the surface (in the latter species the mesoepisternum is less obviously microreticulate with numerous small variably shaped punctures over the entire surface); the basal margin of the elytra is weakly biangulate (strongly biangulate in M. inflammabilis ); the pronotum is densely punctured in the central quarter with relatively large transversely elliptical punctures (in M. inflammabilis the central quarter is sparsely punctured with much smaller punctures many of which are round, not elliptical); the prosternal process is strongly widened from the base, moderately densely punctured in the centre with small round punctures, and moderately densely clothed with fairly long silvery pubescence (in M. inflammabilis the prosternal process is slightly widened from the base, sparsely punctured at the centre with pin-prick punctures, and glabrous or with a few very short setae). In addition to the characters previously mentioned it differs from all the other described species of the group in having the basal margin of the elytra weakly biangulate (moderately strongly to strongly biangulate to biarcuate in the other species).

The following modification to the key to the species of the M. pusilla group in LEVEY (2012) will enable this species to be differentiated from the other species in the group.

1 Apical ventrite of abdomen with contiguous lunate punctures, punctures not forming grooves. ...................................................................................................................... 1A

– Apical ventrite of abdomen with coalescent punctures forming grooves. ................... 2

1A Anterior margin of prosternum with a well defined bead; prosternal process strongly widening from base; base of elytra weakly biangulate; pronotum densely punctured in central quarter with transversely elliptical punctures. ........................ M. bilyi sp. nov.

– Anterior margin of prosternum without a bead; prosternal process only slightly widening from base; base of elytra strongly biangulate; pronotum sparsely punctured in central quarter with small round punctures. .................. M. inflammabilis Thomson, 1879

Etymology. This species is named after my friend and colleague Svata Bílý on reaching his 70 th year, in recognition to all of the excellent work he has produced in adding to our knowledge of the Buprestidae .

Distribution. Australia: Queensland.

Figures

Figs 1–5. Melobasis bilyi sp. nov.: 1 – dorsal habitus, 2 – pronotum.3 – prosternum, 4 – aedeagus. 5 – apical ventrite.