Taxonomic remarks, phylogeny and evolutionary notes on the leaf beetle species belonging to the Cryptocephalus sericeus complex (Coleoptera: Chrysomelidae: Cryptocephalinae)
Author
Sassi, Davide
text
Zootaxa
2014
3857
3
333
378
journal article
10.11646/zootaxa.3857.3.2
9682bd87-ff66-4cb6-b697-9a53822a5df0
1175-5326
231616
55FBFBCF-F9AF-4EAF-A74A-9A81E6A381B8
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.