Olethrius Thomson, 1861

Jin, Mengjie, Keyzer, Roger De, Hutchinson, Paul, Pang, Hong & Ślipiński, Adam, 2020, A Review Of The Australian Macrotomini (Coleoptera: Cerambycidae: Prioninae), Annales Zoologici 70 (1), pp. 33-96 : 68-69

Olethrius Thomson, 1861

( Fig. 12 )

Olethrius Thomson, 1861: 316 . Type species Olethrius tyrannus Thomson, 1861 , by monotypy.

Opheltes Thomson, 1864: 306 . Type species Opheltes auriculatus Thomson, 1864 (= Mallodon macrothorax Montrouzier, 1861 ), by original designation. Synonymised by Lameere 1920.

Diagnostic combination (Male). Large beetles, 30–85 mm long. Dorsum usually uniformly dark brown, sometimes with yellowish or reddish elytra. Sexually dimorphic dense punctures present on pronotum and ventral side of thorax, except two elevated smooth islands in the centre of pronotal disc. Head narrower than prothorax; frontoclypeal suture straight or broadly angulate; median groove complete. Antennal tubercles weakly prominent, directed laterally, rounded at apex. Eyes medium size, weakly emarginate near antennal insertion, moderately separated dorsally. Mandibles 0.3–0.5 times of head capsule length, broad at base, weakly bent and unidentate apically; sexual dimorphism expressed by longitudinal carina on dorsal surface. Antenna extending beyond middle of elytra in Australian species but can reach elytral apex in some other species. Scape slightly shorter than head capsule length, posteriorly extending to anterior margin of pronotum; cylindrical or slightly flattened, gradually expanded; antennomere 3 distinctly shorter than scape and slightly longer than 4. Mentum not fused to submentum. Terminal palpomere of maxillary and labial palps weakly expanded and rounded apically. Prothorax transverse with lateral carina weakly dentate; anterior and posterior margins with complete beads. Pronotal disc uneven with weakly elevated smooth shiny callosities on densely punctate background. Prosternal process sub-parallel, extending to mesoventrite, rounded or narrowly pointed apically. Elytral surfaces punctate, punctures variable in different species; inner apical angle with sharp spine. Legs strong; femo- ra and tibiae surface with dense tiny nodules. Protibia without lateral spines, with one sharp projection and a pair of subequal spurs apically; lobes on tarsomere 3 moderate or extremely large, tarsomere 5 as long as or longer than tarsomeres 1 and 2 combined.

Description. Male. Length 32–82 mm. Dorsum usually uniformly dark brown, elytra sometimes yellowish or reddish brown. Head slightly transverse, narrower than pronotum. Mandible with dorsal surface bearing longitudinal carina and dense setae along incisor edge; length of mandibles variable in different species, but at least longer than half of head capsule length, apex moderately curved inwards; each mandible wedgeshaped, thick and strong on lateral side and near the base, unidentate at apex, with one or two extra teeth on incisor edge. Labrum narrow, dorsal surface covered with long golden setae. Frontoclypeal suture straight or broadly angulate. Antennal tubercles weakly prominent, distant to each other, apex rounded. Antenna 11-segmented, filiform, extending at least beyond middle of elytra, in some species reaching to elytral apices; scapes long, longer than 2/3 of head capsule length. Eyes transverse, coarsely facetted, very weakly emarginate near antennal foramen; moderately separate dorsally. Submentum straight at apex, mentum well exposed. Terminal palpomere of maxillary and labial palps weakly expanded and rounded apically. Pronotum sub rectangular and transverse, usually with prominent anterior angles; complete bead present on both anterior and posterior margins; lateral margin sharp with rather small and short teeth. Disc uneven with shiny elevated triangular admedian islands among dense punctures elsewhere. Prosternum covered with fine and deep punctures; hypomeron welldefined, distinctly broader than prosternal process. Prosternal process projecting towards mesoventrite, sub-parallel with narrowly pointed apex. Mesoventral process emarginate at apex; surface flat. Ventral side of pterothorax and hind coxae covered with golden hairs. Metanepisternum slightly narrowing posteriorly. Scutellum narrowly rounded apically, surface rather smooth and shiny. Elytra surface with variable punctures and pubescence in different species: in O. tyrannus tyrannus elytra with fine sparse punctures entirely and recumbent fine yellowish white sparse pubescence; in O. tyrannus salomonum elytra with fine sparse punctures on base, and only sparse hairs along lateral margin; in O. laevipennis elytra smooth and completely glabrous; in O. scabripennis elytra with dense coarse punctures entirely. Elytra without traces of wing venation; elytral apices rounded with distinct and sharp sutural spine; epipleuron broad, complete, narrowing apically. Legs strong and moderately long; femur sub-parallel and relatively flat, surface very rough, covered with dense tiny nodules especially on front legs, ventral side without short spines apically; each tibia with distinct apical projection and a pair of strong spurs; tarsi moderately strong; tarsomere 3 with median or large lobes; tarsomere 5 as long as or longer than tarsomere 1 and 2 combined. Abdominal ventrites with sparse long hairs or few fine punctures, but bearing dense long setae along the edges, especially on the apex of ventrite 5. Male genitalia. Tegmen longer than sternite VII; parameres moderately long, rounded apically with triangular projections at the base; penis as long as tegmen, dorsal apex about truncate while ventral apex narrowly pointed.

Female. Mandibular surface without longitudinal carina. Pronotal disc with coarser punctures on sexual punctate area; fine and dense punctures on prosternum absent.

Remarks. The genus Olethrius was discussed by Vitali (2008) who clarified taxonomic statuses of many species in the Australo-Pacific Region. According to this publication potentially two or three species may occur in Australia, however all the Australian records are based on very old and doubtfully labelled specimens, including the type locality of O. lavipennis Vitali said to be “ Australia ”. We have examined Prioninae collections from all the major world and Australian museums and found only a single specimen of Olethrius tyrannus salomonum labelled “Richmond River”, the locality located in the northern New South Wales, which is unlikely locality for this species. Mitochondrial genome was generated for this particular sample.

Figures

Figure 12. Olethrius spp. A, B, G, J: O. scabripennis Thomson; C, D, H, K: O. tyrannus tyrannus Thomson; E, F, I, L: O. tyrannus salomonum Vitali. A, C, E: male, dorsal; B, D, F: male, ventral; G–I: male mouthparts, dorsal; J–L: elytral surface.