Cionus congoanus Hustache, 1932

Caldara, Roberto & Košťál, Michael, 2023, A Taxonomic Revision Of The Afrotropical Species Of The Weevil Genus Cionus (Coleoptera: Curculionidae), Zootaxa 5288 (1), pp. 1-98 : 10-12

1. Cionus congoanus Hustache ( Figs 1a–f )

Cionus congoanus Hustache, 1932a: 59 .

Type locality. Dindi ( Democratic Republic of the Congo).

Type series. This species was described from five specimens collected at Dindi in the Democratic Republic of the Congo. We did not find these specimens but only one specimen labelled “Muséum Paris Ogooué Lambarèné [ Gabon], R. Ellenberger 1912 / Cionus congoanus Hustache det. ” ( MNHN) perfectly corresponding to the detailed original description.

Diagnosis. Pronotum with four protuberances emphasized by tufts of yellowish scales. Prosternum with distinct emargination. Elytra with interstria 3 moderately carinate at base, others with protuberances and tufts of scales, striae distinctly sinuate. Tibiae with mucro in male. Claws symmetrical in both sexes.

Redescription. Male ( Figs 1a–b ). Body: stout, globose. Head: rostrum stout, short (Rl/Rw 3.45–3.60; Rl/Pl 1.21–1.26), black, in lateral view regularly moderately curved; in dorsal view slightly gradually widening from base to apex, strongly punctate-carinate, from base to near apex with recumbent to suberect, moderately dense, moderately long (l/w 5–6), intermixed grayish and brown scales. Head between eyes narrow, 0.4× as wide as rostrum at base. Eyes flat. Antennae blackish, inserted between middle and apical third; scape long (l/w 8); funicle half as long as scape, S1 slightly more robust than and as long as S2, 2.5× as long as wide, S2 2.5 × as long as wide, S3–5 as long as wide; club distinctly elongated, oval, moderately longer than funicle, densely pubescent. Pronotum: black, with four protuberances, median ones stouter than lateral ones, with dense irregular moderately deep punctures, intervals among punctures shining, smooth, moderately visible between recumbent, moderately dense, intermixed whitish and black scales, darker scales forming tufts on protuberances and two short vittae between median protuberances and base (l/w 4–7); subconical, distinctly transverse (Pw/Pl 1.48–1.55), widest at basal third, sides moderately rounded in basal half and slightly concave in apical half, weakly convex on disc. Prosternum: anterior margin with distinct emargination, almost reaching procoxae. Scutellar shield: triangular, with dense whitish scales. Elytra: black, globose, slightly wider than long (El/Ew 0.90–0.95) widest at midlength, moderately wider than pronotum (Ew/Pw 1.30–1.36), humeri strongly prominent, rounded, sides moderately rounded, distinctly convex on disc; interstriae strongly sinuate, flat to distinctly convex, partly strongly callous (interstriae 3, 5, 7 and 9), moderately visible behind sparse, irregularly arranged, shallow, small punctures; scales whitish (sparse) and black, darker scales covering convex parts of interstriae, long (l/w 7–10), recumbent but erect on calli, moderately dense; striae moderately visible, with irregularly arranged deep punctures, half as wide as interstriae. Venter: Mesosternal process flat, weakly emarginated. Metathoracic episterna with distinct spot of long, whitish scales. Abdomen with dense punctures, irregular in size and arrangement, and clearly visible between sparse, hair-like, whitish scales, of same shape; V1 and V2 moderately convex, V1 1.6× longer than V2; V1+2 4.9× longer than V3+4, the latter ones 0.5× as long as V5. Legs: femora black, with stout sharp teeth, with indistinct striae of moderately dense whitish and black scales; tibiae black, all with mucro; tarsi black, onychium as long as T1–3 combined; claws symmetrical. Penis: Figs 1d–f , its body gradually narrowed to apex, with blunted tip. Flagellum moderately long, bifurcated at its base.

Female. Rostrum slightly longer (Rl/Rw 3.65–3.75; Rl/Pl 1.27–1.30) ( Fig. 1c ).

Variability. Length 3.7–4.2 mm. The specimens examined showed low variability. The light scales covering scutellum, a part of metathoracic episterna and of elytra are sometimes yellowish.

Remarks. The pronotal and elytral protuberances appear more distinctly pronounced due to the tufts of scales covering them. They actually are small in specimens without scales. This is the unique Afrotropical species with tibiae bearing mucro at least in male and one of the few with symmetrical claws also in the male. As regards to the separation of the genera, the inclusion of this species in Cionus is questionable, because these characters are unusual in this genus ( Caldara & Korotyaev 2002): a mucro was observed only in C. helleri from Far East and Japan, a character never emphasized previously ( Košťál & Caldara 2019). Cionus congoanus might be related to species of the genus Cleopus , which possess both mentioned characters but lack the emargination of the prosternum, or to species of the genera Stereonychus and Stereonychidius which are characterized by a single tarsal claw. It is noteworthy that the presence of protuberances on pronotum and elytra and large elytra seem to approach C. congoanus more to some species from Madagascar, such as C. callosus , than to other species from the African mainland.

Biological notes. No available data.

Distribution. West, Central and East Africa ( Guinea, Cameroon, Equatorial Guinea, Gabon. Democratic Republic of the Congo, Uganda).

Non-type material examined. GUINEA: Guinea (3, BMNH). CAMEROON: Buea, 1000 m, 2.–7.III.1912, leg. V. Rothkirch (2, ZMHB). EQUATORIAL GUINEA: Fernando Po [= Bioko], leg. Báguera (1, MCNM); Nkolentungan, XI.1907 – V.1908, leg. Tessmann (1, ZMHB). GABON: Ogooué Lambarèné, 1912, leg. Ellenberger (1, MNHN). DEMOCRATIC REPUBLIC OF THE CONGO: P.N.A., secteur nord riv. Musinini affl. Byangolo, 1225 m, 14.IV.1958, leg. Vanschuytbroeck (1, MRAC). UGANDA: NW Beni, W of Ruwenzori, forest, I.1908 (3, ZMHB); Bugoma forest, Unyoro, 3700 ft., 1–5.XII.1911 (1, BMNH); Kampala, Nambadzidza, 19.IV.1931, leg. Hopkins (2, BMNH); Kawanda, 10.III.1942, leg. Taylor (2, BMNH); Mboga, SW of Albert-See, III.1908 (1, ZMHB).

Figures

FIGURES 1–2. FIGURE 1. Cionus congoanus. a: body in dorsal view (male), b: body in lateral view (male), c: rostrum in lateral view (female), d: penis in ventral view, e: penis in lateral view, f: apex of penis in dorsal view. FIGURE 2. Cionus coniungens sp. n. a: body in dorsal view (male), b: body in lateral view (male), c: rostrum in lateral view (female), d: penis in ventral view, e: penis in lateral view, f: apex of penis in dorsal view. Not to scale.