Ceresium atricolle, Yokoi, 2019

Ceresium atricolle View in CoL sp. nov.

Figs 8A- B, 22A- I

Types. Holotype Ƌ: “N-Sumatra, Aik Tarum, Diehl 1.I-84” ( ZSM).

Diagnosis. Medium-sized. Almost entirely black. Antennae long. Venter thickly clothed with pale hairs.

Etymology. The name refers to the colour of pronotum.

Description

Measurements. TL = 11.6 mm; EL/EW = 2.94; HW/PW = 0.97; PL/PW = 1.14; PA/PW = 0.75; PB/PW= 0.92.

Colour. Black. Femora and antennal articles 1-6 reddish black, segments 7-11 testaceous.

Head. Frons almost square though emarginated on sides; not steep; horizontally depressed in the middle; shiny; sparsely furnished with large punctures; clothed with pale, stout, curly, rather adpressed hairs, though the apical half naked near middle. Vertex strongly concave between antennal supports; lustreless; punctured as frons but more strongly setose along the upper eye-lobes. Occiput only shallowly punctured. Eyes separated from one another by 1 / 3 the width of occiput. Antennal supports rather raised though without tubercle. Antennae long, well surpassing elytral apices by the last three articles. Scape feebly arcuate and clavate; 1.25×, 1.55 × and 0.95 × as long as 3 rd, 4 th and 5 th article respectively. Articles 1-4 shallowly and minutely punctured; 3-11 more or less whitish pubescent; articles 1-4 additionally fringed with pale short hairs on the underside and at apex.

Pronotum as in Figure 8B, lustreless with microstructures; longer than wide; sub-cylindrical, though sides feebly double-sinuate and constricted near apices. Disc setose as head, though basal margin more densely clothed with short adpressed hairs; densely provided with shallow punctures of varying sizes; median stripe in the basal half naked and nitid.

Scutellum bell-shaped; whitish pubescent.

Elytra moderately long; closely furnished with setiferous punctures of medium-size; finer so toward apices. Hairs on discs shorter than those of comparable species.

Legs. Hind legs rather long. Hind femora slenderer and less clavate than fore and mid ones.

Venter. Prosternum punctured as pronotum; more setose with longer hairs pointing to the basal middle. Prosternal process narrow; widely emarginated on apex. Mesosternum a little raised in middle; obtusely punctured; thickly clothed with pale, recumbent hairs near sides. Mesosternal process moderately broad; with apex thickened and deeply emarginated; rather thickly clothed with pale hairs. Metasternum shiny in middle; clothed otherwise as mesosternum.

Abdomen. 1 st to 4 th visible sternites thickly clothed with pale recumbent hairs near sides. 5 th narrowed toward apex, which is widely and weakly emarginated in the middle.

Genital organs as in Figure 20A- I View Fig . Median lobe about 2 / 5 the length of abdomen; nearly fusiform in dorsal view, though delated toward base; moderately arcuate in profile; dorsal plate dehiscent in basal 11 / 20; ventral plate longer than dorsal plate, dehiscent in well over basal 4 / 5. Tegmen 4 / 5 the length of median lobe; moderately arcuate in profile.Parameres about 1 / 3 the length of tegmen; dehiscent in apical 2 / 5, with each lobe gradually narrowed to apex which is rounded and furnished with short to medium setae. Ejaculatory duct complex as in Figure 20F- H View Fig ; rather narrow and slender in profile; apical sclerite apicad dehiscent, with each lobe strongly bent downwards and hooked; basal sclerite long, parallel-sided, thin and apicad dehiscent. 8 th sternite broad; thickly bordered on sides; triangularly emarginated on apex with latero-apical corners well rounded; clothed with medium to long setae on apex and sparsely so with short, stout setae on apical half; with short peduncle. 8 th tergite as wide as the corresponding sternite, semi-spherical; clothed with hairs of medium length on apex and with several shorter hairs on sides.

Distribution. North Sumatra, Indonesia.

Comparative notes. This new species can be compared to C. femoratum Aurivillius, 1927 , C. flaoicorne Aurivillius, 1927 , C. raripilum Newman, 1842 or C. rouyeri Pic, 1943 . All of them are almost entirely black in colour, their pronotal surfaces more or less closely provided with medium-sized punctures. Antennae of the new species are, however, distinctly longer. Further, punctures on pronotum are shallower and hairs on elytra shorter. C. femoratum and C. flaoicorne differ additionally regarding the colour of legs or antennae, while C. raripilum and C. rouyeri differ with the presence of erect hairs on pronotum and legs.

Longer antennae and moderately raised antennal supports are suggestive of the closely related genus Examnes ( Pascoe 1869) . Its frons is, however, neither short nor steep. In addition, the new species is slenderer than C. philippensis , the nominotype of Examnes , and other members of the genus.

Remarks. Holotype was found among “indet.” specimens in “Hüdepohl Collection” (ZSM). A label with “ Examnes undet.” was attached. In view of the above observation, however, it should be described as a Ceresium species, not as an Examnes .