Cionus Clairville

Košťál, Michael & Caldara, Roberto, 2019, Revision of Palaearctic species of the genus Cionus Clairville (Coleoptera: Curculionidae: Cionini), Zootaxa 4631 (1), pp. 1-144 : 7-8

Cionus Clairville

Cionus Clairville, 1798: 66 (type species: Curculio blattariae Fabricius, 1792 (= Curculio alauda Herbst, 1784 )). Germar,

1821: 299. Schoenherr, 1838: 722; 1845: 178. Reitter, 1904: 49; 1912: 84; 1916: 232. Wingelmüller, 1914: 187; 1921: 102;

1937: 143. Kôno, 1930: 149. Hustache, 1932: 336. Roudier, 1957: 46. A. Hoffmann, 1960: 1211. Tempère & Péricart, 1989:

269. Alonso-Zarazaga & Lyal, 1999: 76. Caldara & Korotyaev, 2002:184. Alonso-Zarazaga et al., 2017: 185.

Mononyx Brullé, 1839: 72 (homonymy, Non Laporte, 1832 (type species Mononyx variegatus Brullé, 1839 )). Uyttenboogaart,

1937b: 115. Alonso-Zarazaga et al., 2017: 185.

Synonyms. Mononyx was described by Brullé (1839) based on a genus type species M. variegatus described in the same publication. This generic name is a junior synonym of Cionus Clairville and primary homonym of Mononyx Laporte, 1832 (Hemiptera) as noticed for the first time by Uyttenboogaart (1937b).

Redescription. Body subparallel to round, 3.00 mm to almost 6.00 mm in size. Head: rostrum length more than pronotum length to less than double pronotum length, in females mostly longer, slender to moderately stout. Head between eyes markedly narrower than rostrum width at base. Eyes large, moderately to broadly rounded. Antennae slender, scape longer than funicle, funicle 5-segmented, club shortly suboval or spindle-shaped to elongate. Pronotum: wider than long, punctured, evenly to unevenly, variously densely covered with elongate scales. With or without shallow to medium deep constriction before anterior margin. Prosternum: peculiar by variously deep emargination on anterior margin, in Palaearctic species without canal. Scutellum: triangular, flat, punctured to rugulose. Elytra: subparallel to broadly rounded, in Palaearctic species with or without dorsal and preapical black tomentous maculae, covered with variously arranged elongate to hair-like fine scales, in some species with erect seta-like scales. Venter: mesosternal process flat to slightly convex, subquadrate to subtriangular, medial part of metasternum in males flat to concave. Ventrites 1 and 2 in males with indistinct to markedly deep and broad impression, in females flat to convex. Ventrites 1–2 combined strikingly longer than ventrites 3–4 combined. Legs: profemora with indistinct to well-marked teeth, meso- and metafemora with large, mostly triangular sharp teeth; covered with recumbent to suberect elongate scales. Tibiae straight to slightly inwardly curved, with vestiture formed by recumbent to erect elongate scales of various color, in some species arranged to lighter transverse scale bands, in both sexes without mucro, only males of C. helleri with mucro. Tarsomere 3 wider than tarsomere 2, bilobed, protarsal onychia in some species in males strikingly elongate, claws at least at base connate, in males in most species of unequal length. Genitalia: body of penis elongate, variously shaped, parameroid lobes absent, penis apodemes, tegmen and tegminal apodemes well-developed. Spermatheca relatively uniform, its corpus stoutly spherical, considerably sclerotized, cornu bent along corpus.

Diagnosis. The genus Cionus can be recognized from other genera of Cionini by one very distinctive character, a more or less sharply incised emargination on the anterior margin of prosternum ( Fig. 62 ). Head between eyes not broader than rostrum at base. The pronotum always longer than wide. The elytra of many Palaearctic species are characterized by one dorsal and one preapical black tomentous perisutural macula, which may be missing in some species. Mesosternal process flat, blunt at posterior margin. Ventrite 1 always longer than ventrites 2–5, ventrites 1–2 combined always remarkably (approximately 2.5 × to 7.0 ×) longer than ventrites 3–4 combined. Male genitalia always without parameroid lobes; spermatheca in Palaearctic species simple, similar in the shape among species, with robust body and long thin, strongly curved cornu, in extrapalaearctic species slightly more complex. Additionally, unlike other genera of Cionini most species of Cionus have unequally long claws in males, especially on protarsi.

Comparative notes. The genus Cionus belongs to the tribe Cionini . The tribe was described by Schoenherr (1825) as “Cionides” giving no specific tribal character but quoting the genus Cionus , and more recently redescribed in details by e. g. Smreczyński (1976) or Caldara & Korotyaev (2002). According to the last authors, the tribe is characterized by eight synapomorphies, of which at least the following ones seem relevant throughout the tribe: “head between eyes narrower posteriorly than anteriorly”, “funicular segment 2 as long as or slightly longer than 1”, “median process of mesoventrite at least half as wide as a coxa”, “uncus on all tibiae absent in females” and “ventrites 1 and 2 much longer (at least 2.6 times) than 3 and 4 [meant combined]”. The tribe contains seven genera distributed worldwide except for the Americas and Australia ( Alonso-Zarazaga & Lyal, 1999). In addition to the typical prosternal emargination, the genus Cionus differs from the following Palaearctic genera by: two claws vs. Stereonychus Suffrian and Stereonychidius Morimoto having only one claw; unequally long claws in males of most species, more or less convex body outline in lateral view vs. Cleopus Dejean having body moderately flat; prominent humeri vs. Nanomicrophyes Pic, 1908 having indistinct humeri; lack of a prosternal canal vs. the likely most related genus Cionellus Reitter having deep prosternal canal.

Biological notes. Host plants of Palaearctic and probably also extra-Palaearctic species belong, as far as known, exclusively to the plant families Scrophulariaceae (mainly the genera Verbascum Linnaeus and Scrophularia Linnaeus ), Paulowniaceae and Buddlejaceae .

Distribution. Palaearctic species occur in almost the entire Palaearctic region except the most northern parts, a large part of the Arabian Peninsula and Palaearctic inner Sahara desert. Additional species-groups of Cionus are native to Afrotropical and Oriental regions.

Figures

FIGURES 61–62. FIGURE 61. Cionus helleri. 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 62. Cionus thapsus. Prosternum, head and coxae in ventral view. Not to scale.