Large-eyed Onthophagus species of Sundaland: a key and descriptions of five new species (Coleoptera: Scarabaeidae)

Seven species of the scarab genus Onthophagus Latreille are keyed and described. They are all characterized by the possession of large eyes (in full-face view), a feature possibly related to nocturnal habits. Traditionally these species are placed in Micronthophagus Balthasar, which is here argued to be a polyphyletic group. Five species are new: paroculus (Sumatra), setoculus (Sumatra), sideki (Sumatra, Borneo), phillippsorum (Borneo), collinsi (Borneo). Of two old species, O. drescheri Paulian and rotundicollis Lansberge, new records are given.