Cryptocephalus

Sassi, Davide, 2014, Taxonomic remarks, phylogeny and evolutionary notes on the leaf beetle species belonging to the Cryptocephalus sericeus complex (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 3857 (3), pp. 333-378 : 334-335

Cryptocephalus subgenus Cerodens Burlini, 1969

Cerodens Burlini, 1969: 539 [subgenus]. Type species: Cryptocephalus kocheri Burlini, 1953 [homonym] (= Cryptocephalus emiliae Burlini, 1956 ), by monotypy.

Ceropachys Burlini, 1953: 75 [subgenus]. Preoccupied genus name, not Ceropachys Costa, 1847 [ Coleoptera : Colydiidae ].

Burlini (1953) established the monotypic subgenus Ceropachys for C. emiliae Burlini, 1956 (= C. kocheri Burlini, 1953 ) on the basis of the peculiar shape of the antennomeres (fig. 5a), which in this species are significantly shortened, flattened and angled along the inner margin. Burlini (1969) changed the name to Cerodens due to homonymy with Ceropachys Costa, 1847 . In Palaearctic species of Cryptocephalus antennomeres are mostly cylindrical, but their shape and length is rather variable in some unrelated groups ( Vela & Bastazo, 2012). The adaptive significance of this variability, if any, remains unknown. Even if in C. emiliae this trait could be considered an utmost in a trend of shortening antennal articles, it is questionable that this condition is so distinct as to justify a separation at subgeneric level (fig. 5a vs. figs 5b–h). This species is undoubtedly placed within the C. sericeus species complex based on molecular data ( Gómez-Zurita et al., 2011), thus the subgenus Cerodens renders Cryptocephalus s. str. paraphyletic.

Besides, on the basis of more traditional considerations, it seems inappropriate to keep the subgenus Cerodens as valid. The recommendations of Platnick (1976) and Wiley (1981) sound particularly suitable for the matter. Supraspecific taxa must express exactly the evolutionary relationships ( Wiley, 1981). In the Darwinian paradigm of descent of species by divergence from a common ancestor, “any existing species must have at least one existing or extinct sister species … [therefore] … “monotypic [sub]genera seem impossible as they must always exclude at least one other species that is a descendent of the most recent ancestor (i. e. they must always be paraphyletic)” ( Platnick, 1976). Besides, according to Wiley (1981), redundant taxa (i. e. taxa adding no additional evolutionary information) should not be produced. For all these reasons, I consider appropriate to propose Cryptocephalus subg.

Cerodens Burlini, 1969 (= Cryptocephalus subg. Ceropachys Burlini, 1953 ) as n. syn. of C. subg. Cryptocephalus s. str. Geoffroy, 1762.