Ceresium nigricolle, Yokoi, 2023

Yokoi, Yaheita, 2023, Note on genitalia and taxonomy of the Callidiopini from the Philippines, with description of six new species and two subspecies (Coleoptera, Cerambycidae, Cerambycinae), Contributions to Entomology 73 (1), pp. 31-66 : 31

Ceresium nigricolle sp. nov.

Figs 6A-G , 21A-C

Type material.

Holotype ♂ (SMF): "Philippines, N. Luzon, Hung-Duan"; "Ifugaon V-2018"; "Cope Collection". (former CJC).

Etymology.

The name of this species refers to the colour of thorax.

Diagnosis.

Bi-coloured, head and prothorax dark, remainder of the body yellowish-brown. Pronotum rounded; disc encircled by a ring of whitish pubescence. Antennae slender and long.

Measurements.

Holotype ♂: TL = 15.4 mm; EL/TL = 0.63; EL/EW = 2.94; HW/PW = 0.86; PL/PW = 1.04; PA/PW = 0.65; PB/PW = 0.90.

Description.

Body yellowish-brown; head, thorax and apices of femora black; setae whitish.

Head narrower than pronotum; glossy; punctures dense, setiferous; setae stout, curved, disorderly, pointing to different directions. Frons transverse, not steep, emarginated on sides, elevated in middle, median furrow short. Vertex broad, moderately concave. Occiput finely sub-rugose; setae pointing to vertex. Eyes separated from one another by 2/5 the width of occiput or 5/3 of the upper eye-lobes; lower lobes densely fringed with short, sub-erect setae. Antennal supports broad, flattened, sub-nitid, though each sub-encircled by an arcuate row of diminutive setiferous punctures. Antennae surpassing elytral apices by 10th article. Length of antennomeres relative to scape: III = 0.84; IV = 0.80; V = 1.2; VI = 1.25; VII = 1.25; VIII = 1.2; IX = 1.13; X = 1.0; XI = 1.1. Scapes weakly clavate, slightly arcuate.

Pronotum slightly longer than broad; sub-spherical with sides almost evenly arcuate. Disc almost encircled by a ring of thick pubescence; bordered by a nitid, irregularly arcuate costa on each side; punctures dense, regular; setae short, curved; pointing to the middle; median stripe broad, about 3/10 the length of pronotum. Sides with a protuberance near each apical corner; punctures dense, variable; setae sparse, short, curved; (Fig. 6B, C ).

Scutellum bell-shaped, pubescent.

Elytra tapering from humeri toward apices; apices separately sub-rounded. Punctures rather small, attenuating towards apices; setiferous. Setae short, stout and curved. Punctures and setae on disc finer.

Legs short and stout. Femora clavate from base on. Tibiae keeled (Fig. 6G ).

Venter (Fig. 6D-F ): Prosternum convex, rounded; the middle apically bordered by a broad, glabrous, horizontal costa; punctures deep and regular; setae curved; sides pubescent. Prosternal process narrow, constricted, apically expanded; apex truncated. Mesoventrite saddle-shaped; with several large, deep punctures in middle; setae sparse in middle, dense on the process, pubescent near sides. Mesoventral process broad; punctures obtuse; sides weakly and apex deeply emarginated. Metaventrite well rounded; glabrous along the median furrow; thickly pubescent otherwise. Abdomen glossy; punctures obtuse; setae recumbent, sparse in middle, denser on sides. 7th sternite trapezoidal; apex widely, weakly emarginated.

Male external genitalia (Fig. 21A-C ): Blade of 8th sternite cotyledonary, well-rounded at corners; regularly fringed with long apical and lateral hairs; apex emarginated in a sinuate line; apical middle with additional short, curved setae; peduncle a little shorter than blade. 8th tergite broadly linguate; apex feebly emarginated; sides and apex fringed with medium to long setae; the apical middle impressed, punctate, with short, curved setae stretching forward; additional setae elsewhere in the apical half pointing to the middle. (Remark: abdomen is damaged, parts of genitalia missing).

Distribution.

Luzon, Philippines.

Comparative notes.

The new species is bi-coloured. A similar colour pattern is also observed in Ceresium bicolor Huedepohl 1994. However, the new species differs in structure and integument of prothorax. In addition, the antennae are longer and slenderer. Regrettably, male genitalia of the new species could not be fully observed. However, its 8th sternite and tergite alone are characteristic enough to distinguish this species. In fact, 8th sternite so well rounded is exceptional. 8th tergite with such setae as of the new species has not been observed before in the genus or tribe.

Figures

Figure 6. A-G. Ceresium nigricolle sp. nov. Holotype male. A. Habitus, dorsal view; B. Head and pronotum, dorsal view; C. Pronotal side; D. Prosternum; E. Meso- and metaventrite; F. Abdomen; G. Protibia.

Figure 21. A-C. Ceresium nigricolle sp. nov. Holotype male. Genitalia (part). A. 8 th sternite, ventral view; B. ditto, with 8 th tergite in the background; C. 8 th tergite, ventral view. Scale bars: 1 mm.