Genus Ypsiloncyphon Klausnitzer, 2009a

(Table 1)

Type species: Cyphon chlorizans Klausnitzer, 1973.

The Australasian species of the genus Ypsiloncyphon were recently revised (Zwick 2014) but their affinities within the large genus were not clarified. Presently, Ypsiloncyphon includes over 50 Asian and about a dozen Australasian species (Table 1, which contains all author names). The genus was established for species with, among other characteristics, a Y-shaped tegmen and a male T9 with apodemes longer than those of T8. Other elements of the male terminalia can take very different forms which made me question the monophyly of the genus (Zwick 2014). Today, various species are known in other Australian marsh beetle genera that are only distantly related but also present the name-giving Y-shaped tegmen (e.g., several Austrocyphon spp., Calvarium (Calvariellum) spp.: Zwick 2013d, 2014).

Presently, four informal species groups within Ypsiloncyphon are separated by diagnostic characters. The definitions of groups 2 and 3 (the latter contains the Australasian species) partly rely on apomorphic characters (Ruta 2007; Klausnitzer 2009) while the definition of group 1 admits a variety of character expressions and is less helpful. The two species in the recently proposed group 4 have asymmetrical penes with setae or spines (Yoshitomi 2015). Unfortunately, many Asian species, also the type species, are incompletely known, with only the habitus and selected details of the male genitalia described.

The description of the type species is supplemented and partly corrected. A new understanding of the groundplan of male terminalia of Scirtinae (Zwick 2015c) is helpful in definitions of monophyla within the genus, in order to determine the relations of the Australasian fauna to the other species. A comprehensive analysis of the Asian fauna is not intended in the present study.