Cryptocephalus violaceus Laicharting 1781
Creators: name: Sassi, Davide
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Chrysomelidae
Cryptocephalus
Cryptocephalus violaceus

description: Cryptocephalus violaceus Laicharting, 1781
Cryptocephalus violaceus violaceus Laicharting, 1781: 514. Type locality: Tyrol, Austria. Type: not examined.
Cryptocephalus violaceus scaffaiolus Burlini, 1961: 94. Type locality: Lake Scaffaiolo, Italy; Holotype in MSNV.
Burlini (1961) proposed to consider the Apennine population of Cryptocephalus violaceus in a restricted area in the vicinity of Modena (near Scaffaiolo Lake) as a subspecies of the nominal form, giving it the name of C. violaceus scaffaiolus. The morphological trait he considered particularly meaningful is the presence of a fairly deep impression on the male anal sternite (fig. 9). This conformation is lacking or only barely visible in specimens of the nominal form of eastern Alps, Balkans and Central and Eastern Europe (fig. 8). On several occasions I have studied many specimens from the area of lake Scaffaiolus and the adjacent territories and I can confirm the constant presence of the morphological peculiarity pointed out by Burlini. Moreover, I can state that, contrary to what was claimed by Burlini, populations from Abetone (about 12 kilometers east of the lake), also belong to this form. The specimens from Scaffaiolo Lake environments also differ for the aedeagal apex being perfectly straight (not slightly curved ventrally) (fig. 2) and almost always with a thin median longitudinal depression (as in fig. 3). The odd issue, however, is that the same morphological characteristics are also always present in C. violaceus from France, Spain and western alpine areas, and surprisingly, no author has previously noted these apparent differences between the eastern and western populations of this species. In the area of central Alps, however, intermediate specimens can frequently be found, that is with aedeagal apex only weakly curved, or anal male pit barely perceptible.
At which taxonomic rank these two forms of C. violaceus are to be awarded is a question that needs to be clarified. In an analogous biogeographic scenario (Sassi, 2011a) for the clade C. aureolus / C. transcaucasicus, I proposed a distinction at specific level, since the two forms, even if showing an area of highly probable hybridization in the Eastern Alps (form " illyricus " sensu Franz, 1949), occur together and are morphologically well differentiated in the neighbourhood of Como, revealing thereby an advanced tendency towards reproductive isolation. With regards C. violaceus, conversely, detectable transitional forms occur along a fairly wide and relatively deep range of central Alps. I found the occurrence of intermediate forms from Valle d'Aosta (Breuil, Champoluc), Piedmont (Macugnaga), Lombardy along the border with Switzerland (Monte Generoso) and even further east to Val Formazza and Vallunga Tartano, but some specimens with faintly intermediate appearance are also found in Veneto (Monte Baldo). This may suggest a lack of reproductive isolation. It is therefore convenient that the separation of the two taxa, given the undoubted biogeographic interest of this evolutionary process, must be recognized and formally framed at subspecific level. For this reason, it seems appropriate to keep the validity of the epithet of C. violaceus scaffaiolus Burlini, encompassing in it all the populations from Spain, France, Western Alps and Northern Apennine.
description: Published as part of Sassi, Davide, 2014, Taxonomic remarks, phylogeny and evolutionary notes on the leaf beetle species belonging to the Cryptocephalus sericeus complex (Coleoptera: Chrysomelidae: Cryptocephalinae), pp. 333-378 in Zootaxa 3857 (3) on page 339, DOI: 10.11646/zootaxa.3857.3.2, http://zenodo.org/record/231616