Xixuthrus Thomson, 1864

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 : 74-75

Xixuthrus Thomson, 1864

( Figs. 13 J–M, 15C , 15R , 18C )

Xixuthrus Thomson, 1864: 296 . Type species Macrotoma microcera White, 1853 , by original designation.

Clinopleurus Lansberge, 1884: 141 . Type species Clinopleurus arfakianus Lansberge, 1884 , by monotypy. Synonymised by Marazzi et al. 2006.

Diagnostic combination (Male). Large beetles, 45–70 mm long. Head and pronotum dark brown while elytra reddish brown. Pronotum without sexually dimorphic dense fine punctures. Head narrower than prothorax; frontoclypeal suture broadly angulate; median groove complete. Antennal tubercles moderately prominent, rounded apically. Eyes transverse, weakly emarginate near antennal insertion, closely separat- ed dorsally. Mandibles about 2/3 length of head, sexually dimorphic on the length, not bending towards ventral side and unidentate apically. Antenna reaching elytra apex. Scape longer than half of head length, posteriorly extending beyond the posterior margin of eye, gradually expanded apically, surface covered with small spines; antennomere 3 longer than scape and antennomere 4. Mentum not fused to sub-mentum. Terminal palpomere of maxillary and labial palps elongate and weakly expanded, apices rounded. Prothorax transverse with lateral carina regularly dentate; anterior margin with incomplete bead while posterior margin with complete bead. Pronotal disc bearing dense adpressed hairs and sparse tiny nodules. Prosternal process sub-parallel, extending to mesoventrite, round- ed apically. Elytra surface covered with adpressed golden hairs; inner apical angle with sharp spine. Legs long, sharp spines present on femora and tibia. Protibia surface very rough with two sharp apical projections and single spur; tarsomere 3 moderately lobed, tarsomere 5 shorter than tarsomeres 1 and 2 combined.

Description. Male. Length 45–70 mm. Dorsum covered with dense adpressed short hairs, head and pronotum dark brown while elytra reddish brown. Head weakly elongate, narrower than pronotum. Mandibles sexually dimorphic, much longer in males, dorsum bearing sparse hairs, apex curved inwards; each mandible wedge-shaped, very thick and strong on lateral side and near the base, unidentate at apex, with two extra teeth on incisor edge. Labrum transversely oval, anterior margin weakly emarginate medially; labrum separated from clypeus by a membrane-like groove; dorsal surface of clypeus with dense adpressed hairs as the remaining head. Frontoclypeal suture angulate; median groove distinct and complete. Antennal tubercles moderately prominent, relatively close to each other, apex rounded. Antennae 11-segmented, filiform, extending towards apex of elytra; scapes long, much longer than eye length. Eyes transverse, coarsely facetted, very weakly emarginate near antennal foramen; closely separated dorsally. Submentum not curved at apex, mentum well exposed. Terminal palpomere of maxillary and labial palps elongate and weakly expanded, apices rounded. Pronotum transverse, almost semi-circle; anterior margin with incomplete bead while posterior margin with complete bead; lateral carina regularly dentate, posterior margin weakly dentate near humeral angle. Disc surface uniformly setose, with sparse tiny nodules. Prosternum with dense irregular punctures; hypomeron welldefined, about same width as prosternal process; prosternal process sub-parallel, projecting towards mesoventrite and rounded apically. Mesoventral process relatively broad, apex emarginate medially. Ventral side of pterothorax and coxae covered with golden hairs. Metanepisternum weakly constricted at both ends. Scutellum rounded or slightly emarginate at apex, surface densely setose. Elytra surfaces covered with golden adpressed hairs, venation present on apical 1/3 of elytra; elytral apices rounded with sharp sutural spine; epipleuron complete, narrowing towards apex. Legs long and strong, femur sub-parallel and relatively flat, surface rough especially on front femur, ventral side with rows of tiny spines; each tibia with two distinct apical projections and single strong spur; tarsi slender; tarsomere 3 moderately lobed; tarsomere 5 shorter than tarsomere 1 and 2 combined. Abdominal ventrites surface completely pubescent, and with dense long setae along the edge, especially on the apex of ventrite 5. Male genitalia ( Fig. 15C ). Tegmen longer than sternite VII; parameres long, about 0.2 times length of entire tegmen, rounded apically without small triangular projections at the base; penis as long as tegmen, dorsal apex broadly rounded while ventral apex narrowly pointed.

Female. Mandibles much shorter than in male, less than half of head capsule length; antennae shorter, only extending to middle of elytra; pronotum trapezoid with relatively distinct anterior angles; surface of antennal scape and front femur rough, but not as strongly dentate as in males; prosternum and hypomeron without dense irregular punctures. Ovipositor ( Fig. 15R ) long, apical sclerosed part less than half of baculus length; distal gonocoxites short and small; stylus inserted laterally and close to gonocoxite apex, relatively long and gradually expanded apically.

Remarks. There are currently 26 species or subspecies recognised in the genus Xixuthrus widely distributed in Indo-Australian region, with single species- X. domingoensis Fisher , from the Dominican Republic (Titan database, Tavakilian and Chevillotte 2019).

Figures

Figure 13. A–C: Pseudoplites hamali (Lameere); D–F:Teispes insularis (Hope); G–I: Utra nitida Jordan; J–M: Xixuthrus microcerus (White). A, D, G, K: male, dorsal; B, E, H: male, ventral; C, F, I, L: female, dorsal; J: apex of protibia, arrow indicate the single spur; M: head, dorso–lateral, arrow indicates not emarginate eye near antennal insertion.

Figure 15. A–C: male genitalia, each figure from left to right: tegmen (ventral), tegmen (lateral), penis (ventral). A: Teispes insularis (Hope); B: Utra nitida Jordan; C: Xixuthrus microcerus (White). D–R: ovipositor. D: Agrianome spinicollis (Macleay); E: Analophus parallelus Waterhouse; F: Anomophysis coxalis (Gahan); G: Archetypus marginatus sp. nov.; H: Brephilydia jejuna (Pascoe); I: Cnemoplites edulis Newman; J: Cryptipus frenchi (Blackburn); K: Eurynassa servillei Thomson; L: Geoffmonteithia queenslanda Jin, de Keyzer et Ślipiński; M: Hagrides princeps (Gahan); N: Hermerius impar Newman; O: Pseudoplites hamali (Lameere); P: Teispes insularis (Hope); R: Utra nitida Jordan; R: Xixuthrus microcerus (White).

Figure 18. Distribution maps based on specimens examined.