RESUMO
Abstract Within the subgenus Dichotomius (Selenocopris) Burmeister 1846, D. nisus (Olivier, 1789) and D. superbus (Felsche, 1901) had been historically arranged in the "Nisus" section by Luederwaldt, however, according to the revised classification of the subgenus, the two species now belong to different species groups. In this paper, the taxonomic history concerning the species once included by Luederwaldt in the "Nisus" section is revised and discussed. The following new synonyms are proposed: Pinotus taunayi (Luederwaldt, 1931) as a subjective synonym of D. geminatus (Arrow, 1913), and Pinotus taunayi pilosus (Luederwaldt, 1931) as a subjective synonym of D. nisus. Lectotypes are designated for D. nisus and Pinotus garbei. Redescriptions, diagnoses and updated distribution data are provided for D. nisus and D. superbus. The diagnostic characters of the male genitalia of these species are described and illustrated for the first time.
RESUMO
ABSTRACT The monospecific subgenus Dichotomius (Homocanthonides) is revised and its single species, Dichotomius (H.) smaragdinus (Perty, 1830) is redescribed and distinguished from other Dichotomius species. Dichotomius (H.) smaragdinus is a polymorphic species and its distribution comprises the Brazilian Cerrado. For the first time, morphological variation and male genital organ are described and illustrated. We believe that this species might be endangered due to extensive deforestation of Brazilian Cerrado by agricultural and pasture expansion. Thus, we highlight the importance of preserving this very unusual Dichotomius species.