Ceresium ikuoyokoii, Yokoi, 2019

Ceresium ikuoyokoii View in CoL sp. nov.

Figs 7A- B, 19A- L

Types. Holotype Ƌ: “ SUMATRA, ACEH, III-89” ( ZSM).

Diagnosis. Small-sized, bi-color. Pronotum unlike any other species of the genus; very voluminous, with peculiar integument.

Etymology. The name of this species is dedicated to late Ikuo Yokoi, younger brother of the author, who continuously supported and encouraged the author for studying the cerambycid fauna of the Asia-Pacific area.

Description

Measurements. TL = 8.5 mm; EL/EW= 2.94; HW/ PW = 0.8; PL/PW = 1.0; PA/PW = 0.66; PB/PW = 0.75.

Colour. Testaceus; head and reticulate part of pronotum fuscus.

Head. Densely furnished with deep, coarse punctures of medium to large size; clothed with yellowish, stout, curly, disarrayed hairs. Frons transversally rectangular, slightly elevated in middle. Vertex very broad, feebly concave, with an obtuse median groove. Eyes moderately large, separated from one another by half the width of occiput. Antennal support flattened. Antennae rather stout and short, hardly reaching the last visible sternite. Scape 1.25 × and 1.33× longer than 3 rd and 4 th article respectively, equally long as 5 th; moderately arcuate and clavate; densely and coarsely punctured; clothed sparsely with short recumbent hairs. Articles 2-11 densely clothed with pale minute hairs; articles 3-9 each additionally fringed with short hairs on the underside.

Pronotum as in Figure 7B. Somewhat resembles that of C. breoipes Pic, 1943 in outline, but even more voluminous; almost as wide as body or elytra; well convex and about as long as wide. Sides very strongly constricted at apex; weakly arcuate in apical half and distinctly so in basal half; moderately constricted near base. Disc reticulate with fusiform meshes in a median trapezoidal area tapering from base toward apical 1 / 8; clothed with two pairs of pale yellow, oblong, tomentose macula; the pair of parallel ones in apical 1 / 3 nearer to each other, the other two arcuate ones oblique in basal 1 / 3 reaching the base. Pronotum otherwise densely and regularly provided with medium-sized, rather coarse punctures; clothed with sporadic, pale yellow, short, disarrayed hair. Apical and basal margins shiny and impunctate in middle.

Scutellum nearly triangular, pale-yellowish tomentose.

Elytra sub-parallel-sided. Disc densely provided with large setiferous punctures each bearing a pale curly hair. Sides and apex less densely so with smaller punctures.

Legs rather short and stout. Femora moderately clavate.

Venter. Prosternum well convex and rounded; densely and regularly provided with medium-sized punctures; furnished sporadically with yellowish, stout, curly hairs; naked and shiny near apical margin. Prosternal process narrow; well-bordered and truncated on apex. Mesosternum also well rounded, with similar integument as prosternum; additionally with thick, longer hairs near sides. Mesosternal process moderately broad; feebly emarginated on apex. Metasternum obtusely punctured; clothed with pale, moderately long, recumbent hairs.

Abdomen shiny, obtusely punctured; rather sparsely clothed with whitish lying hairs. 5 th visible sternite weakly narrowed apicad; with apex truncated.

Genital organs as in Figure 19A- L View Fig . Median lobe about 2 / 5 the length of abdomen; bullet-shaped and rather short in dorsal view; moderately arcuate in profile; dorsal plate dehiscent in basal 11 / 20; ventral plate equally long, dehiscent in basal 3 / 4. Tegmen nearly 4 / 5 the length of median lobe, broad in dorsal view; weakly double-sinuous in profile. Parameres about 2 / 5 the length of tegmen, dehiscent in apical 1 / 3; with each lobe strongly narrowed toward apex which is rounded and furnished with short to medium setae; dorsally provided with several horizontal furrows near middle. Ejaculatory duct complex as in Figure 19F- H View Fig ; apical sclerite long, flattened, apicad largely dehiscent; basal sclerite sharply bent upward; ejaculatory duct itself broad and flattened. 8 th sternite bi-lobed like a ginkgo leaf, though moderately emarginated on apex; clothed with medium to long setae on apex and sides. 8 th tergite as wide as the corresponding sternite; semi-spherical; with hairs of short to medium length on apex. 7 th sternite similar in outline as 8 th tergite; clothed with short, stout setae near apex. 9 th tergite thinly stretched on spicum gastrale; more than 3 / 4 circular; well sclerotized.

Distribution. Sumatra, Aceh, Indonesia.

Comparative notes. Pronotum of this new species is peculiar, differing from those of all the other known species of the genus Ceresium . C. breoipes or C. grandicolle Holzschuh, 2015 shares an analogously large pronotum, though not quite reaching the volume of the new species. Structure, setae and colour of pronotal surface are, however, obviously different. C. striaticolle Holzschuh, 2011 has also a rather large pronotum with striate surface and macula. The pronotum is, however, different in outline. As to genital organs of the new species, not only 8 th sternite, ejaculatory duct or spicum gastrale, but also the outline and surface of tegmen is rather singular in the genus.

Remarks. Holotype was found among “indet.” specimens in “Hüdepohl Collection” (ZSM).