Mecinus circulatus (Marsham)

Caldara, Roberto & Fogato, Valter, 2013, Systematics of the weevil genus <i> Mecinus </ i> Germar, 1821 (Coleoptera: Curculionidae). I. Taxonomic treatment of the species, Zootaxa 3654 (1), pp. 1-105 : 49-51

27. Mecinus circulatus (Marsham)

Figs 25 , 72–73 , 127 , 149 , 164

Curculio circulatus Marsham, 1802: 274 .

Mecinus circulatus (Marsham) . Rosenschoeld, 1838: 779. Tournier, 1874: 43. Bedel, 1885: 148; 1887: 311; 1923: 72. Desbrochers des Loges, 1893: 59. Rey, 1894: 74. Reitter, 1907: 11. Hustache, 1931: 401, 406. Hoffmann, 1958: 1266, 1274. Angelov, 1971: 117. Smreczyṅski, 1976: 26. Lohse & Tischler, 1983: 261.

Lixus marginatus Beck, 1817: 20 . Germar, 1821: 318.

Mecinus fimbriatus Germar, 1821: 318 .

Mecinus limbatus Dejean. 1821: 98 ; 1836: 327 (nomen nudum).

Mecinus sericatus Betta, 1857: 62 . Caldara & Colonnelli, 2012: 91.

Mecinus nasutus Tournier, 1873: 85 ; 1874: 44. Reitter, 1907: 12.

Mecinus brevithorax Desbrochers des Loges, 1893: 60 ; 1908: 95. Reitter, 1907: 12. Hoffmann, 1958: 1275.

Mecinus horridulus Desbrochers des Loges, 1893: 60 ; 1908: 95. Reitter, 1907: 11. Hustache, 1931: 406. Hoffmann, 1958: 1275.

Mecinus angustulus Desbrochers des Loges, 1893: 61 . Reitter, 1907: 9. Hoffmann, 1958: 1275.

Mecinus circulatus var. albipubens Reitter, 1907: 12 . Hustache, 1931: 406. Hoffmann, 1958: 1275 (infrasubspecific name).

Mecinus angustulus var. rufipennis Pic, 1915: 27 . Hoffmann, 1958: 1275.

Type locality. United Kingdom. Type series. Mecinus circulatus was described from specimens from Britannia (currently the United Kingdom) without more detailed indications. In Marsham's collection there is a specimen which agrees with the current concept of this taxon and might be a syntype (R. T. Thompson pers. comm.) .

Synonyms. We did not find syntypes of Lixus marginatus ( Germany) and M. fimbriatus (Odenbach, Germany). We follow the opinion of all the previous authors, who considered these taxa as synonyms of M. circulatus .

Dejean (1821; 1836) quoted the new name M. limbatus , subsequently always considered as synonymous with M. circulatus , without adding a description: therefore the name is a nomen nudum and is not available according to Art. 12 of ICZN (1999).

Mecinus sericatus was described by Betta from specimens from Lombardy (northern Italy) no longer available. According to the original description Caldara & Colonnelli (2012) designated the neotype of this species and synonymized it with M. circulatus .

We have not found syntypes of M. nasutus , described from specimens from Sicily. Based on the original description we believe Reitter's opinion (1907), which considered this taxon as a variety of M. circulatus , to be correct.

M. horridulus was described from male specimens from Dalmatia and Etruria (an ancient region of central Italy), the latter from Faust's collection, without more precise indications. In Desbrochers des Loges' collection (MNHN) we examined one male labelled “Dalmatie / male / horridulus / Ex Musaeo Desbrochers des Loges, 1914” (lectotype here designated). M. brevithorax was described from specimens from Greece (Faust's collection), without more precise indications. We examined three syntypes of this taxon: one female in Desbrochers des Loges' collection (MNHN) labelled “ Aegina Ietz Faust , brevithorax / Ex Musaeo Desbrochers des Loges, 1914” (lectotype here designated) and one male and one female (SMTD) glued on the same card and labelled “ Aegina, Oertzen , brevicollis Desbr. det. / brevithorax m. male female / Cotypus” (paralectotypes). Mecinus brevithorax and M. horridulus were considered as varieties of M. circulatus by Reitter (1907) and Desbrochers des Loges (1908) and we agree with this opinion.

M. angustulus was described from male specimens from Algeria without more detailed indications. In Desbrochers des Loges' collection (MNHN) we examined a male syntype labelled “Algérie / angustulus / Ex Musaeo Desbrochers des Loges, 1914” (lectotype here designated).

The variety albipubens of M. circulatus was described from specimens from southern France and Istria (Monfalcone, currently in Venezia Giulia, Italy) clearly as an infrasubspecific taxon (ICZN 1999 Art. 45.6.1). Therefore this name is unavailable (ICZN 1999 Art. 45.5). However we examined two females of this variety (HNHM) labelled respectively “Sommières, E. Tisson / v. albipubens M. / Holotypus, 1907, Mecinus circulatus var. albipubens Reitter ” and “Istriaen / Montfalcone, Reitter / Paratypus, 1907, Mecinus circulatus var. albipubens Reitter ”, which actually are within the range of variability of M. circulatus .

The variety rufipennis of Mecinus angustulus was described from specimens from Algeria (Oued el Kheir) and must be considered as a subspecies according to Art.45.6.4 of ICZN (1999). We examined one male of this taxon in Pic's collection (MNHN) labelled “Oued el Kheir, 17 mai / type / TYPE / angustulus v. rufipennis Pic ” (lectotype here designated). As referred to by Hoffmann (1958), it is only a specimen of M. circulatus with reddish integument, probably a immature specimen.

Redescription. Male. Length 2.7 mm. Body: long, cylindrical, moderately slender ( Fig. 25 ). Rostrum: black with reddish apex, moderately short (Rl/Pl 0.67), subcylindrical; in lateral view moderately curved, weakly narrowed in apical third ( Fig. 72 ); in dorsal view with subparallel sides, with moderately visible scrobes, distinctly striate-punctured to near apex, with wider and deeper sulcus along midline, in basal two thirds with recumbent, somewhat dense, whitish, long (l/w 7–10), seta-like scales. Head: frons as wide as rostrum at base, without fovea; eyes weakly convex. Antennae: reddish with brown club, inserted just in front of middle of rostrum; scape moderately short, 3.5x longer than wide; funicle distinctly longer than scape, segment 1 1.5x longer than wide, stouter and twice as long as segment 2, which is as long as wide, segments 3–5 distinctly transverse; club long, oval, segment 1 almost glabrous. Pronotum: black, with dense and regular punctures, intervals between punctures flat, smooth and shining, clearly visible especially on disc between recumbent, sparse, whitish (arranged along midline and sides where are denser) and greyish brown, long to very long (l/w 7–15), seta-like scales; weakly transverse (Pw/Pl 1.15), with weakly rounded sides, with weakly prominent apical constriction, widest at basal third, weakly convex. Elytra: reddish except interstriae 2–5 and 9 and 10, which are black; long (El/Ew 1.62), cylindrical, at base weakly concave, slightly wider than pronotum (Ew/Pw 1.16), with parallel sides, somewhat convex on disc; interstriae clearly visible between recumbent to suberect, moderately dense, greyish brown, long to very long (1.0–1.5x as long as width of interstria; l/w 7–15), seta-like scales, which are arranged in 3–4 irregular rows; striae hardly visible, one third narrower than interstriae, with a row of scales similar to shorter ones covering interstriae. Legs: stout, with recumbent to suberect, moderately dense, greyish, seta-like scales, which are shorter than width of tibia; femora reddish and brown, subclavate, profemora with very small tooth; tibiae reddish, short; protibiae with apical part of ventral surface somewhat directed outward; unci dark brown, stout, all equal in length; tarsi reddish, tarsomere 1 1.5x longer than wide, tarsomere 2 about as long as wide, tarsomere 3 bilobed and distinctly wider than tarsomere 2, onychium slightly shorter than tarsomeres 1–3 taken together; claws dark brown, equal in length, fused in basal half. Venter: metasternum black, distinctly convex, clearly visible between recumbent to subrecumbent, sparse, whitish, long, seta-like scales; mesothoracic epimera and meso- and metathoracic episterna with somewhat dense, whitish, long seta-like and wide fringed scales; abdomen black, with somewhat dense and regular punctures, which are clearly visible between recumbent to subrecumbent, sparse, whitish, long, hair-like scales; ventrites length ratio: 1–2/3–4 1.85. Penis: fig. 127.

Female. As in male except rostrum longer (Rl/Pl 0.77), distinctly curved at base, subcylindrical ( Fig. 73 ), weakly punctured, antennae inserted at middle of rostrum. Sternite 8: fig. 149. Spermatheca: fig. 164.

Variability. Length 2.6–2.9 mm. The sides of the pronotum are more or less rounded. The colour of the elytral integument varies from almost completely black to completely reddish. The elytral scales may be recumbentsubrecumbent for the most part or suberect-erect.

Remarks and comparative notes. Due to the colour of the elytral integument, with black and reddish vittae, and the elongate and cylindrical body M. circulatus might be confused with three other uncommon species with limited distribution: M. humeralis , M. suturalis and M. tanaiticus (see comparative notes of these taxa). It is easily distinguishable from M. comosus , which has a short and subconical rostrum, and from M. alternans , which has the elytra distinctly wider than the pronotum.

Biological notes. Larvae feed on the collar of Plantago lanceolata L., where they dig tunnels without producing external deformations ( Hoffmann 1958). Adults were also collected on P. psyllium L., P. cynops L. and P. subulata L. ( Hoffmann 1958; Sprick 2001).

Distribution. Western, central and southern Europe, northern Africa, Middle East.

Non-type specimens examined. About 200 specimens from United Kingdom, Portugal, Spain, France, Italy, Malta, Croatia, Greece, Cyprus, Algeria.

Figures

FIGURES 19–27. Habitus of (19) Mecinus henrici; (20) M. elongatus; (21) M. alternans; (22) M. tanaiticus; (23) M. reichei; (24) M. humeralis; (25) M. circulatus; (26) M. suturalis; (27) M. pyraster. Not to the same scale.

FIGURES 69–77. Rostrum in lateral view of (69) Mecinus tanaiticus, male; (70) idem, female; (71) M. humeralis, female; (72) M. circulatus, male; (73) idem, female; (74) M. pyraster, male; (75) idem, female; (76) M. baridioides, male; (77) idem, female. Scale bar = 0.5 mm.

FIGURES 121–132. Penis in dorsal and lateral view of (121) Mecinus desertorum; (122) M. marina; (123) M. henrici; (124) M. alternans; (125) M. reichei; (126) M. tanaiticus; (127) M. circulatus; (128) M. humeralis; (129) M. pyraster; (130) M. comosus; (131) M. simus; (132) M. pirazzolii. Scale bar = 0.2 mm.

FIGURES 144–156. Sternite 8 of (144) Mecinus pascuorum; (145) M. caucasicus; (146) M. marina; (147) M. reichei; (148) M. humeralis; (149) M. circulatus; (150) M. pyraster; (151) M. simus; (152) M. collaris; (153) M. janthinus; (154) M. lixoides; (155) M. sicardi; (156) M. heydenii. Scale bar = 0.2 mm.

FIGURES 157–171. Spermatheca of (157) Mecinus pascuorum; (158) M. caucasicus; (159) M. haemorrhoidalis; (160) M. labilis; (161) M. marina; (162) M. elongatus; (163) M. reichei; (164) M. circulatus; (165) M. pyraster; (166) M. simus; (167) M. comosus; (168) M. lixoides; (169) M. janthinus; (170) M. heydenii; (171) M. collaris. Scale bar = 0.2 mm.