Gymnetron crassirostre Lucas, 1849

Caldara, Roberto, Casalini, Roberto & Baviera, Cosimo, 2012, Taxonomic and nomenclatural notes on the Rhinusa tetra (Fabricius) species complex (Coleoptera: Curculionidae), Zootaxa 3329, pp. 31-40 : 35

Gymnetron crassirostre Lucas, 1849

This taxon was described from specimens from Chevrolat's collection collected in the surroundings of Algiers. It was compared with R. tetra and said to differ by the smaller and narrower body and mainly by the distinctly shorter and more curved rostrum. Lucas (1849) illustrated habitus, rostrum in lateral view and antenna. Brisout de Barneville (1862) considered this taxon as a variety of R. tetra with yellow vestiture but, after examination of a syntype, placed it in synonymy with G. verbasci Rosenschoeld (Brisout de Barneville, 1865). In Klima (1934) and Hoffmann (1958), G. crassirostre is considered as a synonym of R. tetra . In Chevrolat's collection at NHRS we found two male specimens, placed next to each other and labelled respectively “425 [handwritten under a round card blue upside and white downside] / crassirost [sic] Lucas - Gymnetron teter Meg. Alger [handwritten upside and downside the same rectangular white thin card]” and “183 [printed on a rectangular white card] / crassirostris Luc Ba[rbarie] [handwritten on a blue rectangular card]”. These specimens are almost identical with the lectotype of G. verbasci (see above) and one of them is probably the specimen that Brisout de Barneville (1865) received from Boheman as a syntype of G. crassirostre . They agree with the original description in the body length of 5 mm, the colour of the elytral integument and the vestiture composed of moderately dense, short, greenish yellow scales, but not at all in the shape of the rostrum (long and straight in lateral view in these specimen vs. very short and distinctly curved in lateral view in Lucas' original description and line drawing). We think that this intriguing conflict can be resolved with another specimen we found adjacent to the previous two specimens. It is the holotype of Gymnetron lanigerum Brisout de Barneville, 1862 (presently R. lanigera ) which is labelled “191. [handwritten under a semicircular card blue upside and white downside] / Gymnetron lanigerum Chv. Barb [arie]. Lucas [handwritten on a blue rectangular card] / 191. [printed on a rectangular white card]”. This specimen corresponds exactly to that illustrated by Lucas as crassisostre. In conclusion we believe that Lucas erroneously combined the characters of two different species in a single description. Therefore, following Boheman's opinion (Brisout de Barneville, 1865). we here designate the first of the two above mentioned male specimens, which is labelled with the number “425”, as the lectotype of Gymnetron crassirostre .