Taxonomic revision of the batesi species group of Dichotomius Hope, 1838, with the description of three new Amazonian species (Coleoptera, Scarabaeidae, Scarabaeinae)

Abstract

Dichotomius (Selenocopris) is amongst the most diverse subgenera of Dichotomius Hope, 1838. Due to the scarcity of material and logistical problems experienced by previous authors to access type specimens, the available taxonomic information for the batesi group is mainly the short and superficial original descriptions of its species. In this paper, we provide a revision for all the species assigned to the batesi group and a comparative study with species belonging to taxonomically related species groups, namely: agenor, geminatus, inachus, carbonarius, and lucasi. The batesi group is redefined to include five Amazonian species: D. batesi, D. ziliolii, D. snethlageae sp. nov., D. martavannucciae sp. nov., and D. leopoldinae sp. nov.. The globulus is proposed for the remaining species formerly included in the batesi group; these species occur from Costa Rica to northern Amazonia. Dichotomius parcepunctatus and D. fortestriatus are considered new synonyms of D. batesi. Distribution data and an identification key are provided for the species in the batesi group.