Nerdanus Fairmaire, 1897

Švihla, Vladimír, 2007, On the taxonomy of the dityline genera Diasclera Reitter, Dityloidea Fairmaire and Germain and Nerdanus Fairmaire (Coleoptera: Oedemeridae), Zootaxa 1619, pp. 45-51 : 48-49

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.