Orthogonius angustus Chaudoir, 1871

Tian, Mingyi & Deuve, Thierry, 2016, Stepwise and cooperative assembly of a cytokinetic core complex in budding yeast Saccharomyces cerevisiae, Belgian Journal of Entomology 42, pp. 1-19 : 1-19

Orthogonius angustus Chaudoir, 1871

Figs 16–18

CHAUDOIR, 1871: 114

MATERIAL EXAMINED. Type material: 1♂, holotype: [ angustus Chaud. / Malaisie/ Siam? Castelnau] ( MNHN) .

Additional material. 6♂: [Coll. I.R.Sc. N.B./ Vietnam: Dong Nai Biosphere Res. ; 11°18’ N, 107°06’ E / 25.VI.- 6.VII.2012, night collecting/ Leg. J. Constant & J. Bresseel /I.G. 32.161] ( RBINS) ; 1♂, ibid ( MNHN) ; 1♂, ibid ( SCAU) ; 10♂, 3♀: [Coll. I.R.Sc. N.B./ Vietnam, Cat Tien N.P. / 11°26’ N, 107°26’ E / 6-16.VIII.2012, Malaise trap / Leg. J. Constant & J. Bresseel /I.G. 32.161]( RBINS) ; 3♂, 1♀: ibid ( MNHN) ; 2♂, 1♀: ibid ( SCAU) .

DESCRIPTION.

Length: 13.0–14.0 mm; width: 4.8–5.0 mm; Habitus as in Fig. 16 . Body small, moderately shiny; brownish to dark brown, head darker than pronotum and elytra; head and pronotum impunctate; elytra finely and sparsely punctured; head and pronotum faintly and indistinctly wrinkled; microsculptures: engraved meshes isodiametric, clear on elytra, unclear on head and pronotum.

Head: stout, as long as wide; eyes very large and prominent; frons and vertex slightly convex, frontal impressions pit-like, small; clypeus bisetose, basal portion with short furrows on both sides and median linking frontoclypeal suture and frontal impressions respectively; labrum six setose, shallowly but widely emarginate at apical margin; palpi slender, subcylindrical, 3 rd maxillary palpomere as long as 4 th which is glabrous; 3 rd one with several short setae at apex; 2 nd labial palpomere as long as 3 rd, bisetose on inner margin, with several additional setae near apex; 3 rd one with a few short setae; ligula small, slightly dilated at apex, bisetose; mentum edentate, both mentum and submentum bisetose; palpigers setose; antennae quite short and rather slender, extending to base of elytra; pubescent from basal 1/3 of 4 th antennomere, slightly expanded at pubescent portion; 3 rd antennomrere as long as 4 th, slightly shorter than 1 st.

Pronotum: strongly transverse, PW/PL=1.5–1.6; disc moderately convex; fore (except for median portion) and basal margins well beaded, sides evenly and roundly expanded, widest at mid-length; posterior margin slightly wider than anterior one, bisinuate, with median portion slightly protruded backwards; anterior margin nearly straight; both fore and hind angles rounded off, but fore angle more rounded; lateral expanded margin well defined, narrow, distinctly reflexed; fore transversal impression faint, hind one well marked; basal foveae large and deep; median line clear.

Elytra: elongate ovate, moderately convex; EL/EW=1.6; widest and not parallel-sided at mid-length; basal border complete; apex obliquely sinuate towards apex, but suddenly and shortly truncate before tip, making inner angle nearly rectangular, without denticle; sutural angle wide and shallow; striae deep, punctate-striate; intervals distinctly convex, subequal in width in middle portion; 3 rd interval with three setiferous pores; 7 th interval simple.

Legs: rather stout, strongly setose; fore tibiae strongly expanded at apex, with outer angle strongly protruded, apical margin concave and outer margin subserrate; middle coxae with several rather long setae medially; hind coxae smooth and glabrous; hind femora strongly expanded, with 4 (male) or 7 (female) posterior setae; middle tibiae short and stout, stouter in female than in male, distinctly curved, with outer margin with two rows of setae, distinctly and strongly serrate; hind tibiae gradually dilated towards apex, with apical spurs very short and broad; fore and midtarsi stout, hind ones much slender; 1 st hind tarsomere much longer than 2 nd (1.3–1.4 times), 3 rd slightly longer than 4 th (1.1–1.2 times) which is asymmetrically bilobed at apex (outer lobe distinctly longer than inner one); fore and midtarsal claws moderately pectinate, hind ones simple.

Ventral side: prosternal process bordered at apex; abdominal ventrite VII evenly and shallowly bisinuate in male; ventrite VII with two pairs of setae on either side of apical margin in both sexes.

Male genitalia ( Figs 17–18 ): very elongate, slender, with median portion enlarged; ventral margin widely bisinuate, gradually narrowed towards apex which is sharp, deeply and suddenly cut near base; dorsal opening long and wide; in dorsal view, apical lamella more or less triangular, longer than wide, apex very broad.

DISTRIBUTION. Southern Vietnam and Thailand. It is here recorded from Vietnam for the first time.

NOTE. There is a confusion concerning the type locality of O. angustus . According to CHAUDOIR (1871), the unique type specimen was given by M. de Castelnau who said that it was collected from “Ngami Lake (Siam)” (possibly Nong Ngam Lake as the Ngami Lake does not exist in Thailand). But M. de Mniszech told Chaudoir that he had a similar individual which was from Malaysia and only different from the type specimen by coloration. So, Chaudoir presumed that the specimen was actually collected from Malaysia, and added a question mark behind “Siam” on the label. Based on the recent discovery of this species in Vietnam, we believe that the type specimen was collected from Thailand.

Figures

Figs 16–18. Orthogonius angustus Chaudoir, 1871. 16. habitus, male; 17–18. aedeagus, lateral view and apical lamella, dorsal view.