Borneostyrax cristatus, 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 : 61-65

Taxon classification Animalia Coleoptera Cerambycidae

Borneostyrax cristatus sp. n. Figs 47-63, 64-67

Type material.

Holotype, male, "Malaysia, Sabah / Tenom / III-12-2008 / local coll // Dolichostyrax / moultoni / Aurivillius / det J. Sudre 06 // HOLOTYPE / Borneostyrax / cristatus Gabriš, Kundrata / & Trnka, 2016 / gen. et sp. n. " (HNHM, ex PCDH). Three paratypes. Female, "Malaysia, Sabah / Crocker Range, vic. / Trus Madi, III-26- / 2000 local coll. // PARATYPE / Borneostyrax / cristatus Gabriš, Kundrata / & Trnka, 2016 / gen. et sp. n. " (PCDH); female, "Malaysia, Sabah / Tongod 500m / III-18-2014 / local coll // PARATYPE / Borneostyrax / cristatus Gabriš, Kundrata / & Trnka, 2016 / gen. et sp. n. " (PCDH); female, "Malaysia: Sabah / Crocker Range / 10 February 2003 / LG Bezark, collection // PARATYPE / Borneostyrax / cristatus Gabriš, Kundrata / & Trnka, 2016 / gen. et sp. n. " (PCLB).

Other material examined.

Female, "Malaysia, Sabah / Sipitang area / IV-11-2002 / local coll ‘Unil‘ // Dolichostyrax / moultoni / Aurivillius / det J. Sudre // Borneostyrax / cristatus Gabriš, Kundrata / & Trnka, 2016 / Gabriš det., 2016" (PCDH).

Description of holotype

(male). BL 10.8 mm, BW 3.9 mm. Body dark brown; appendage joints lighter, palpi 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; anterior margin of anteclypeus shallowly emarginate, with sparse long yellowish semi-erected setae. Labrum 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 about as long as body; scape enlarged, slightly curved, longest, reaching the second half of pronotum, gradually widened towards apex, with sparse yellow semi-erect setae, the rest of antennomeres with much sparser and thinner setae, pedicel very small, shortest, the relative ratio of antennomere lengths 2.9: 0.3: 1.0: 1.0: 0.8: 0.6: 0.6: 0.5: 0.5: 0.6: 0.8, antennomere III relatively narrow (length/width ratio = 3.4-3.6; Fig. 51). Mandibles short and broad; apex bidentate (Fig. 52). Maxillary palpi and labial palpi with ultimate palpomere widened apically, flattened, apex truncate (Fig. 53).

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 distinct tubercles near middle and two median at first and second half, respectively; pronotal tubercles sparsely punctured; anterior and posterior angles obtuse. Scutellum transverse, about three times as wide as long. Elytra elongate, 1.7 times as long as wide at widest part, 2.1 times as long as pronotum; 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). Legs long, slender; femora weakly swollen distally, tibial spurs 0-0-2, tarsal formula 4-4-4, relative lengths of metatarsomeres 1.0: 0.5: 0.8: 1.4.

Abdomen with five ventrites; first ventrite (excluding intercoxal process) about 1.5 times longer than second; intercoxal process short, broadly rounded. Fifth ventrite with apex broadly rounded, 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).

Description of female.

Most characters same as for males. BL 12.6-14.6 mm, BW 4.9-5.5 mm. Body reddish brown to brown; appendage joints lighter, palpi brown. Antennae 0.8-0.9 times as long as body length. Maxillary and labial palpi with ultimate palpomeres fusiform (Fig. 7). Pronotal tubercles less distinct; tubercles smooth or with individual punctures. Elytra elongate, 1.6-1.7 times as long as wide at widest part, 2.1-2.5 times as long as pronotum. Legs long, slender; tibial spurs 2-2-2; protibiae and mesotibiae without wide apical protrusions on inner faces, relative lengths of metatarsomeres 1.0: 0.5-0.6: 0.8-0.9: 1.2-1.7. Abdomen with first ventrite (excluding intercoxal process) more than 1.5 times longer than second; fifth ventrite with apex truncate. Female genitalia with ovipositor short, wide, apically with short styli (Fig. 63). Vagina sac-like, large, with pair of vaginal plates. Spermatheca absent.

Remark.

Two females contained large larvae (two and three, respectively) inside their abdomens. The larvae filled most of the females’ abdomens and were located with their heads oriented towards the abdominal base (Fig. 64). Apparently, there were thin egg shells at least partly covering the larvae, but unfortunately, we were not able to specify where exactly in internal genitalia were larvae localized due to the partly damaged thin membranous structures inside the female internal reproductive organs. This damage was caused by the dissection because of two factors - first, the presence of larvae in the female abdomen was an unexpected finding as (ovo)viviparity has not been reported for any long-horned beetle to date, and second, it was studied in dry material, re-moistened only before the dissection.

Description of larva.

Body up to 7.0 mm long and 1.6 mm wide, elongate, subcylindrical, creamy white, heavily sclerotized head capsule and mandibles darker (Fig. 65). Head capsule (Figs 66-67) 1.7 mm long and 1.3 mm wide, prognathous; anterior margin of cranium with long erect setae; medial endocarina extending to clypeus. Clypeus membranous, broad, trapezoidal. Labrum free, broadly rounded apically, sparsely setose. Antennae very small, terminal antennomere reduced, narrow. Mandibles broad, slightly curved, basally with long sparse setae. Maxillary palpi 3-segmented, api cal palpomere elongate, narrow, longer than palpomere II. Labial palpi 2-segmented. Legs absent. Thoracic and abdominal segments not sclerotized, laterally sparsely setose; last two segments bearing also long erect setae dorsally.

Distribution.

Malaysia: Borneo (Sabah).

Etymology.

The specific name refers to the distinct ridges of tubercles on elytra (Fig. 48).