Microichthyurus robusticeps Pic, 1923

Lin, Hanqing, Liu, Haoyu, Yang, Xingke & Yang, Yuxia, 2025, Taxonomy of the genus Microichthyurus Pic (Coleoptera, Cantharidae, Chauliognathinae), with descriptions of nine new species from China, Deutsche Entomologische Zeitschrift 72 (1), pp. 27-56 : 27-56

Microichthyurus robusticeps Pic, 1923

Figs 1 A, B , 2 A, B , 3 A , 4 A ‒ D , 5 A, B

Microichthyurus robusticeps Pic, 1923: 57.

Material examined.

Vietnam • 1 ♂ 1 ♀; Tonkin; Hoa-Binh ; A de Cooman leg.; IZAS . LAOS • 1 ♂ 3 ♀♀; Vang Viene ; 27-VI-2015; Haoyu Liu leg.; MHBU • 2 ♂♂ 2 ♀♀; Phon Khao Khouay National Bio-Diversity ; 160 m; 29-VI-2015; Haoyu Liu leg.; MHBU .

Re-description.

Body length (both sexes): 3.5‒3.8 mm; body width (both sexes): 0.8‒0.9 mm.

Male (Fig. 1 A ). Coloration. Body black, head and pronotum with blue metallic luster; antennomeres I ‒ III yellow; elytra gray at apical 1 / 3 parts; legs gray at coxae and trochanters; abdomen light yellow at anterior and posterior margins of ventrites II ‒ VI.

Eyes strongly large, interocular distance about half as wide as diameter of an eye, head width across eyes distinctly wider than anterior margin of pronotum. Antennae extending to posterior margin of abdominal tergite IV, antennomeres II ‒ III, V, and VII subequal in length and about half length of I, III ‒ IV, and VIII ‒ X cylindrically thickened, IV about 0.8 times as long as III, VI about 1.2 times as long as V, VIII ‒ X progressively shortened, XI fusiform and about twice longer than X.

Pronotum 1.2 times wider than long, anterior margin slightly arcuate, posterior margin strongly bisinuate, lateral margins slightly converging posteriorly, anterior angles rounded, and posterior angles nearly rectangular. Elytra as long as wide, 1.5 times longer than pronotum, with lateral margins subparallel, sutures strongly dehiscent from the base, distance between sutures nearly as wide as width of the elytron, apices rounded.

Abdominal tergite VIII (Fig. 2 A ) about 1.1 times longer than wide, with lateral margins nearly straight, postero-lateral projections about 1 / 3 length of the tergite and nearly straight at inner margins. Abdominal sternite VIII (Fig. 2 B ) bilobed, with lateral portions converging posteriorly to each other, sickle-shaped and acute at apices, slender and 4.0 times as long as basal width, bisinuately emarginate at basal parts of inner margin, where covered with a few erected and stout setae. Proctiger (Fig. 3 A ) peach-like, completely surrounded by paraproct, covered with some slightly long setae on surface. Paraproct (Fig. 3 A ) well-developed, narrowed posteriorly, and shallowly emarginate at posterior margin, covered with a few long setae, with tergal flange extremely long, almost 4.0 times as long as paraproct, slightly wider at base, and bent inwards.

Aedeagus (Fig. 4 A ‒ D ): left ventral paramere rod-like, straight and slender, slightly swollen at apex (Fig. 4 A, B ); left dorsal paramere about 1.3 times as long as left ventral paramere, very slender and spiral, acute at apex (Fig. 4 C ); right paramere short and lamellar, about 2 / 5 length of left ventral paramere, widely rounded at apical margin (Fig. 4 C ); median lobe moderately sclerotized, grooved at basal part and conical tube-shaped at apical half, rounded at apex, about half length of parameres (Fig. 4 A, B ); internal sac elongate tube-shaped, on which surface densely covered with numerous short setae.

Female (Fig. 1 B ). Similar to males, but antennae simple and filiform. Abdominal tergite VIII (Fig. 5 A ) about 1.2 times longer than wide, with lateral margins arcuate, lateral projections about 1 / 4 length of the tergite and slightly arcuate at inner margins. Abdominal sternite VIII (Fig. 5 B ) about 1.1 times longer than wide, with lateral margins moderately converging posteriorly, posterior margin nearly straight, and latero-apical angles rounded.

Distribution.

Laos, Vietnam.

Remarks.

Although the type of this species was not located in Muséum national d’histoire naturelle, Paris, France ( MNHN), it could be easily recognized by its characteristic large head and bicolored elytra ( Pic 1923). It is recorded in Laos for the first time.

Figures

Figure 1. Habitus of Microichthyurus, dorsal views. A ‒ B. M. robusticeps Pic, 1923; C ‒ D. M. falcatus sp. nov. A, C. holotype males; B, D. paratype females. Scale bars: 2.0 mm.

Figure 2. A ‒ B. M. robusticeps Pic, 1923; C ‒ D. M. falcatus sp. nov. A, C. male abdominal tergite VIII, ventral view; B, D. male abdominal sternite VIII, ventral view. Scale bars: 0.2 mm.

Figure 3. Proctiger and paraproct of Microichthyurus species, ventral views. A. M. robusticeps Pic, 1923; B. M. falcatus sp. nov. Abbreviations: p – proctiger; pp – paraproct; tf – tergal flange. Scale bars: 0.2 mm.

Figure 4. Aedeagi of Microichthyurus species. A ‒ D. M. robusticeps Pic, 1923; E ‒ H. M. falcatus sp. nov. A, E. ventral views; B, F. right-lateral views; C, G. left-lateral views; D, H. dorsal views. Abbreviations: ldp – left dorsal paramere; lvp – left ventral paramere; rp – right paramere; ml – median lobe. Scale bars: 0.2 mm.

Figure 5. A ‒ B. Microichthyurus robusticeps Pic, 1923; C ‒ D. M. falcatus sp. nov. A, C. female abdominal tergite VIII, ventral view; B, D. female abdominal sternite VIII, ventral view. Scale bars: 0.2 mm.