Borneostyrax, Gabris, Radim, Kundrata, Robin & Trnka, Filip, 2016

Gabris, Radim, Kundrata, Robin & Trnka, Filip, 2016, Review of Dolichostyrax Aurivillius (Cerambycidae, Lamiinae) in Borneo, with descriptions of three new genera and the first case of (ovo) viviparity in the long-horned beetles, ZooKeys 587, pp. 49-75 : 59-61

Taxon classification Animalia Coleoptera Cerambycidae

Genus Borneostyrax gen. n.

Type species.

Borneostyrax cristatus sp. n.

Diagnosis.

This genus is unique within Bornean Morimopsini by having bidentate mandibular apex (Fig. 52) and elytra with tubercles forming distinct ridges (Figs 48, 60) in both sexes; tibial spurs 0-0-2, distinct protrusions on apices of protibiae and mesotibiae (Fig. 54), and terminal maxillary and labial palpomeres widened, flattened and truncate in males (Fig. 53), and short, wide ovipositor, large sac-like vagina and missing spermatheca in females (Fig. 63).

Description.

Body robust, elongate, 10.8 mm long and 3.9 mm wide in male, and 12.6-14.6 mm long and 4.9-5.5 mm wide in females. Body reddish brown to dark brown; appendage joints lighter, palpi brown to black. Body very densely clothed with very short golden brown pubescence; scape, legs, scutellum, apex of elytra and abdominal ventrites covered with longer sparse semi-erected yellow setae (Fig. 47).

Head about as wide as anterior margin of pronotum; genae convex at frontal view; frontoclypeus with distinct midline running from interantennal groove to labrum, sparsely punctured, punctures deep with setae inside; antennal tubercles prominent with moderately deep depression in between; antennal cavities opened dorsally; anterior margin of anteclypeus shallowly emarginate, with sparse long yellowish semi-erected setae. Labrum free, transverse, glabrous, covered with long, sparse semi-erect setae, apical margin with short dense pubescence (Fig. 50). Eyes moderately-sized, vertically elongate, emarginate at antennal articulations, lower lobes slightly narrower than genae. Antennae 11-segmented, about as long as body in male and 0.8-0.9 times in females; scape enlarged, slightly curved, longest, reaching the second half of pronotum, gradually widened towards apex, thickest at apical part, with sparse yellow semi-erect setae, the rest of antennomeres with much sparser and thinner setae, pedicel very small, shortest, the relative length ratio of antennomeres I–IV 2.4-2.9: 0.2-0.3: 1.0: 0.9-1.0; antennomere III relatively narrow (length/width ratio = 3.4-3.6; Fig. 51); antennomere V slightly shorter than antennomere IV, antennomeres VI–X subequal in length, antennomere XI shorter than antennomere III. Mandibles short and broad; apex bidentate (Fig. 52). Maxillary palpi 4-segmented, ultimate palpomere with apical half widened, flattened, apex truncate in males; ultimate palpomere fusiform in females (Fig. 53). Labial palpi 3-segmented, ultimate palpomere with apical half widened, flattened, apex truncate in males; ultimate palpomere fusiform in females.

Prothorax sub-cylindrical, as long as wide, widest at middle, laterally with one small obtuse tubercle; pronotal disc weakly convex, sparsely covered with deep puncturation, with pair of more or less distinct tubercles near middle and two median at first and second half, respectively; pronotal tubercles smooth or sparsely punctured; anterior and posterior angles obtuse. Prosternum in front of coxae 0.7 times shorter than diameter of coxal cavity, sparsely punctured; procoxal cavities circular, narrowly separated (Fig. 49). Scutellum transverse, about three times as wide as long. Elytra elongate, 1.6-1.7 times as long as wide at widest part, 2.1-2.5 times as long as pronotum, basally wider than posterior pronotal margin, widest slightly after middle, then gradually tapered towards apex, fused along the elytral suture; each elytron with three rows of prominent irregular tubercles forming distinct ridges (Figs 47-48), sparsely covered with large deep punctures located irregularly in rows; elytra covered with very dense short pubsecence, apically with sparse long erected yellowish brown setae; outer elytral margin curved at lateral view (Fig. 48). Mesoventrite with anterior edge on different plane than metaventrite. Both mesoventrite and metaventrite without puncturation. Mesocoxal cavities circular, separated wider than in procoxal cavities. Metaventrite transverse, more than two times wider than long, posterior margin emarginated, with short narrow median emargination. Metacoxal cavities separated slightly wider than in mesocoxal ones, extending laterally to meet elytra (Fig. 49). Hind wing absent. Legs long, slender; femora weakly swollen distally, tibial spurs 0-0-2 in male, 2-2-2 in females, protibiae with pubescent groove (antennal cleaner) on inner face, inner face apically prolonged forming distinct, wide, gradually tapered protrusion in male (Fig. 54), simple in females; mesotibiae with pubescent groove on outer face, inner face with distinct protrusion as in protibiae but shorter in male, simple in female; metatibiae without groove, without protrusion; tarsal formula 4-4-4, relative lengths of metatarsomeres 1.0: 0.5-0.6: 0.8-0.9: 1.2-1.7; last tarsomere with four long erected setae at ventral face, claws simple, empodium absent.

Abdomen with five ventrites; first ventrite (excluding intercoxal process) about or slightly more than 1.5 times longer than second; intercoxal process short, broadly rounded. Fifth ventrite with apex broadly rounded in male, truncate in females, margin with very sparse semi-erect pubescence. Male genitalia with tegmen elongate, widest at posterior 1/3, basally with long strut; parameres short, distinctly shorter than phallobase, apically with short fine setae (Figs 57-58). Penis weakly curved at lateral view, apically acuminate; dorsal struts diverged before 1/2 of penis length. Internal sac moderately long, with paired short medial and distinct flagellar sclerites (Figs 55-56). Female genitalia with ovipositor short, wide, apically with short styli (Fig. 63). Vagina sac-like, large, with pair of vaginal plates. Spermatheca absent.

Etymology.

The name Borneostyrax is a combination of words “Borneo” (geographical origin of the genus) and “styrax” (part of the generic name Dolichostyrax ). Gender: masculine.