Cionus variegatus ( Brullé, 1839 )

Košťál, Michael & Caldara, Roberto, 2019, Revision of Palaearctic species of the genus Cionus Clairville (Coleoptera: Curculionidae: Cionini), Zootaxa 4631 (1), pp. 1-144 : 97-98

58. Cionus variegatus ( Brullé, 1839)

Figs 58 a–f.

Mononyx variegatus Brullé. 1839: 72 . Zumpt, 1937: 227 ( Cionus variegatus ). Roudier, 1957: 46 ( Cionus variegatus ). Caldara, 2013: 124 ( Cionus variegatus ). Machado & Oromí, 2000: 228. Alonso-Zarazaga et al., 2017: 186 ( Cionus variegatus ).

Cionus luctuosus Boheman, 1845: 179 . Wingelmüller, 1914: 221; 1921: 110; 1937: 203. Roudier, 1957: 46. Machado & Oromí, 2000: 228. (syn. n.). Caldara, 2013: 124. Alonso-Zarazaga et al., 2017: 186.

Type locality. Canary Islands .

Type series. The species was described from “ Canary Islands ” without giving an exact locality and the number of specimens. We did not find the type material in coll. Brullé ( MNHN). However, a detailed original description referring to the peculiar black and white vestiture of C. variegatus “Joli insecte varié de noir et de blanc...” leaves no doubt about the identity of the described taxon, which cannot be confused with any other weevil on the islands .

Synonyms. Cionus luctuosus was described from Tenerife based upon an unknown number of specimens. In coll. Schoenherr ( NHRS), where Boheman´s types are deposited, there is a pinned, 4.75 mm long female labeled “1078 / Typus / Coll. Chevrol.”, which perfectly corresponds to the original descriptions of both Mononyx variegatus and Cionus luctuosus . Therefore, these two species are surely conspecific. We designated the female as the lectotype of Cionus luctuosus Boheman by adding the label “ LECTOTYPUS Cionus luctuosus Boheman M.Košťál et R.Caldara des.2011 [printed red label]” and identified the species as C. variegatus .

Redescription. Male. Body medium stout, suboval. Head: rostrum medium stout, medium long (l/ w 4.9, Rl/Pl 1.46), black; in lateral view very slightly, somewhat unevenly curved, upper outline at antennal insertion slightly abruptly curved, lower outline evenly slightly curved, in basal part of same width from base to antennal insertion, in apical part tapered to apex; in dorsal view same width from base to antennal insertion, then slightly broadened to apex, in basal part round in cross-section, in apical part dorsoventrally flattened; confluently, longitudinally punctured except smooth matt median longitudinal apical area; basal part with mostly upwardly oriented, recumbent, thin, whitish and brownish intermixed scales, in apical part with forwardly oriented, subrecumbent, long pale seta-like scales. Head between eyes narrow, of 0.4 rostrum width at base. Eyes very large, rounded, not protruding from head outline. Antennae black to blackish-brown, inserted at 2/3 of rostrum length; funicle of 0.7 scape length, segment 1 wider than segment 2, segment 1 1.5 ×, segment 2 more than three times as long as wide, segments 3–5 as long as wide; club elongate, more than 2.5 × as long as wide, completely covered with recumbent thin pale and dark hairs, and sparse erect, relatively short pale sensilla. Pronotum: black, markedly wider than long (Pl/Pw 0.62), very densely punctured, punctures subrotund, of almost equal size, spaces between punctures considerably smaller than puncture diameter; semidensely covered with recumbent, slightly elongate black scales, on sides entirely covered with light scales, in mediobasal area with large, longitudinal medial band formed by recumbent whitish to yellowish elongate (l/w 4–6) scales; widest at base, subparallel to slightly convergent to half of pronotal length, then abruptly subconically narrowed to anterior margin, with shallow but distinct wide constriction, in lateral view in basal half flat, then abruptly falling to anterior margin. Prosternum: anterior margin with sharply incised, deep subquadrate incision bounded by tubercles, separated from coxae by narrow prosternal area. Scutellum: triangular, with whitish scales similar to those in white elytral pattern, densely punctured. Elytra: black, in basal 2/3 subparallel to slightly rounded, in apical third broadly slightly unevenly rounded, moderately elongate (El/Ew 1.25), widest at about 1/3 of their length, at base somewhat wider than pronotum (Ew/Pw 1.69), humeri subrotund to subquadrate, moderately prominent, with posthumeral impression; moderately convex on disc; interstria 1 at about 1/3 of medial length and in preapical area broadened, interstria 2 at same lengths narrowed and constricted laterally encompassing medium large subrotund black tomentous maculae without differently colored scale border; interstriae except perimacular area of approximately equal width; odd interstriae without patches of scales; striae shallow, formed by single, almost even rows of deep round punctures; entire surface completely covered with densely arranged, recumbent, moderately elongate black scales and recumbent elongate (l/w 3–6), whitish scales forming striking “black and white” pattern, large white areas almost confluently covering elytral sides including apex and dorsum, especially periscutellar area, with smaller white irregular maculae, both types of scales fully concealing elytral integument. Venter: unevenly densely covered with whitish hairs and broader scales, whitish to yellowish clusters of scales on metepisterna, sides of metasternum, sides of ventrite 2 and paramedially on ventrites 3–5; mesosternal process flat, posterior margin straightly truncated, covered with fine hairs, densely punctured to rugulose; metasternum concave, densely punctured, ventrite 1 with medium deep impression, ventrite 2 flattened, both ventrites punctured; ventrite 1 1.7 × as long as ventrite 2, ventrites 1–2 combined 4.4 × as long as ventrites 3–4 combined, ventrites 3–4 combined of 0.9 of ventrite 5. Legs: black except brown claws, profemora without teeth, only with tuft of erect scales, mesofemora with small blunt, metafemora with slightly larger blunt teeth; femora covered with recumbent to subrecumbent, whitish and dark intermixed elongate scales forming incomplete to almost complete transverse whitish bands, tibiae covered with intermixed recumbent to suberect whitish and dark elongate scales, tarsi with suberect, thin, whitish seta-like scales except onychia being covered with recumbent, thin, whitish hairs; protarsal onychia shorter than tarsomeres 1–3 combined, tarsomere 3 wider than long; protarsal lateral, meso- and metatarsal medial claws by about 1/4 shorter and indistinctly thinner than their pair-claws. Penis: Figs 58 d–f, its body relatively short, widest in middle, abruptly bluntly tapered to apex.

Female. Rostrum longer (Rl/Pl 1.77), in lateral view without abrupt curvature at antennal insertion, evenly moderately curved, of same width from base to apex, antennal insertion at 0.6 of rostrum length. Ventrites 1 and 2 without impression. Claws of approximately equal length.

Variability. Length ♂♂ 3.98 - 4.62 mm, ♀♀ 4.35–4.82 mm. This species shows remarkable variability in the white elytral pattern in periscutellar and dorsal perimacular area. In some specimens the white spots are almost missing, whereas in others they are confluent, surrounding scutellum and dorsal macula. Otherwise, shape, texture and shape ratios are minimally variable.

Diagnosis. Cionus variegatus is very easily recognizable by completely concealed elytral integument, striking black and white elytral pattern, elongate antennal club, wider pronotum, reduced to absent femoral teeth, and shape of penis.

Comparative notes. This species is most closely related to C. griseus , from which it differs by more elongate antennal club, shorter pronotum, more striking elytral pattern, and penis shape.

Biological notes. Stüben & Behne (2013) reported this species from Gomera on Verbascum virgatum Stokes , which surely concerns the nutritional feeding of imagoes. In the same paper the authors report Scrophularia sp. as a collecting plant from several places in Gomera. Subsequently, Stüben & Behne (2015) reported S. glabrata Aiton as a collecting plant from two localities on La Palma (718 and 1362 m a. s. l.) and mentioned also S. smithii langeana (Bolle) Dalgaard as a host plant. According to Bramwell & Bramwell (1990), S. glabrata occurs at high elevations of 1,600 –2,400 m a. s. l. whereas S. smitghii langeana is found in elevations up to 800 m a. s. l. Therefore, and based on numerous specimens examined by us exclusively from lower elevations, e.g. one male from Tenerife collected on “ S. smithii ” at 800 m a. s. l. (MZLU), the above mentioned observations indicate that the true host plant of C. variegatus is probably S. smithii langeana with uncertain monophagy.

Distribution. This species is endemic to the Canary Islands (Tenerife, Gomera and La Palma).

Non-type specimens examined. We examined 67 specimens from all three Islands. Tenerife (Las Mercedes, Mt. Aguirre), Gomera (El Cedro, Monte El Cedro, Espigon de Ibosa), La Palma (unspecified localities).

Figures

FIGURES 57–58. FIGURE 57. Cionus wittei. 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. FIGURE 58. Cionus variegatus. 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.