On the taxonomy of the dityline genera Diasclera Reitter, Dityloidea Fairmaire and Germain and Nerdanus Fairmaire (Coleoptera: Oedemeridae)
Author
Švihla, Vladimír
text
Zootaxa
2007
1619
45
51
journal article
10.5281/zenodo.179148
3af5092e-bc0e-4272-8cfc-8a9e0e8e3d32
1175-5326
179148
Nerdanus
Fairmaire, 1897
Nerdanus
Fairmaire, 1897
: 239
.
Type
species:
Nerdanus coeruleus
Fairmaire, 1897
, by monotypy.
Redescription.
Male. Body slender, slightly convex in cross section. Both mandibles bifid at apex, last maxillary palpomere slender, subparallel. Eyes small, moderately protruding, reniform. Antennomeres from fourth onwards becoming wider and flatter terminally, antennomere 11 suboval, moderately spoon-shaped. Pronotum subparallel, very slightly cordiform, with only indistinct prebasal depression, anterior depressions absent. Femora more or less curved, tibiae moderately curved, posterior ones widened, with slight, obtuse central keel and with semierect spines on its inner side. Terminal spines of anterior tibiae shortened, inconspicuous, basal tarsomeres of anterior tarsi enlarged and flattened, claws simple. Elytra parallel-sided, with slight, but clearly visible venation. Both last tergite and sternite subtriangular, emarginated apically, apical portions of urite VIII wide and flattened. Tegmen shortened, feebly sclerotized, parameres distinctly divided, aedeagus slender, ca. twice as long as tegmen, with subapical tooth. Female unknown.
Differential diagnosis.
The genus
Nerdanus
should be referred to the tribe
Ditylini
, as defined by
Švihla (1986)
, based on the shape of male terminalia. It is related to the predominantly Oriental genus
Ascleranoncodes
, distributed from the southern slopes of the Himalayas southwards and eastwards to the
Philippines
and Seram island, because of synapomorphies such as shortened tegmen, derived form of antennae and slender body form, which are unique within the dityline genera. However, the genus
Nerdanus
differs from
Ascleranoncodes
because of the flattened antennomeres (thickened and cylindrical in
Ascleranoncodes
) and strongly derived anterior tarsi and posterior tibiae.
Distribution.
The only known species occurs on the island of Sulawesi,
Indonesia
.