Rafael V. Nunes

New brachypterous species of Dichotomius Hope, with taxonomic notes in the subgenus Luederwaldtinia Martínez (Coleoptera: Scarabaeidae: Scarabaeinae)

An overview of the subgenus Dichotomius (Luederwaldtnia) and its species groups is presented with species groups proposed and a provisional identification key provided. Dichotomius (Luederwaldtnia) vidaurrei, a brachypterous new species from Bolivia, is described. Another brachypterous species, from Brazil, D. mysticus (Luederwaldt) is redescribed. Dichotomius paraguayanus Gandini & Aguilar is synonymized with Canthidium kelleri (Martínez, Halffter & Pereira). Some aspects of the evolution of flightlessness in Dichotomius are discussed.

Taxonomic revision of the Dichotomius speciosus (Waterhouse, 1891) species group (Coleoptera: Scarabaeidae: Scarabaeinae)

The Dichotomius speciosus species group, endemic to the highlands of the Brazilian Atlantic Forest and included in the subgenus Luederwaldtinia is taxonomically revised. Dichotomius alvarengai new species and D. malyi new species are described. Dichotomius bucki is here considered to be a new synonym of D. opalescens, for which a lectotype is designated. The group, as well as its species, is diagnosed. A taxonomic key, illustrations and discussions on systematics and conservation of the group are provided.

New brachypterous species of Dichotomius ( Selenocopris ) Burmeister (Coleoptera: Scarabaeidae: Scarabaeinae) with the definition of species groups and taxonomic notes in the subgenus

Five species groups of Dichotomius (Selenocopris) are defined and separated in an illustrated key in the first effective attempt of systematization of the subgenus. Four new brachypterous species of Selenocopris are described and the also brachypterous Dichotomius ingens (Luederwaldt) is redescribed. These species are diagnosed, illustrated and assigned to the quadraticeps species group. Taxonomic issues on the subgenus are discussed.

New species, redescription and taxonomic notes in the Dichotomius ( Luederwaldtinia ) batesi (Harold) species-group (Coleoptera: Scarabaeidae: Scarabaeinae)

This paper deals with taxonomic issues of the Dichotomius (Luederwaldtinia) batesi (Harold) species-group. We describe Dichotomius benesi n. sp. from Panama, and redescribe and designate a lectotype for Dichotomius ocellatopunctatus (Felsche) from Venezuela, both hemi-brachypterous species. We also do brief comments on the taxonomy of this species-group. Dichotomius joelus, previously assigned to this group, is here considered to be a new synonym of D. opacipennis and then to belong to Dichotomius geminatus species-group.

A new species of Holocephalus Hope from Paraguay (Coleoptera: Scarabaeidae: Scarabaeinae: Dichotomiini s. str.)

It came to us from Svatopluk Pokorný a single Scarabaeinae specimen from Paraguay which we promptly diagnosed as belonging to the genus Holocephalus Hope, mainly due to the shape of first labial palpomere, head, cephalic carina, pronotum and other secondary charateristics (Smith & Génier 2001, Vaz-de-Mello et al. 2011). Comparisons with the diagnosis provided in the very fine and comprehensive revision of the genus (Smith & Génier 2001) and with specimens deposited at CEMT (Cuiabá-MT, Brazil) allowed us to confirm that this exemplar belongs to a new species of Holocephalus, which is described here. Besides providing illustrated description and diagnosis of the sixth discovered species of the genus, we differentiate it in a Holocephalus key adapted from Smith & Génier (2001) and also provide additional geographical records for other species in the genus.

Taxonomic composition of Scarabaeinae dung beetles (Coleoptera: Scarabaeidae) inhabiting fluvial islands in the southern Brazilian Amazon

Summary We evaluated the taxonomic composition of Scarabaeinae dung beetles inhabiting fluvial islands in Juruena River, southern Brazilian Amazon. We sampled seven islands and two localities on each side of the mainland. We collected 41 species, all of which are widely distributed in the Amazon rainforest. Nine of these were exclusive to the islands, 24 were exclusively found on the mainland while eight species were found in both the islands and the mainland. The insular dung beetle fauna is mainly composed of typical species of várzea forest or edge forest/gap with the absence of Eurysternus and elements of primary forest in the Amazon. This result suggests that three main processes are shaping these communities: flooding and associated disturbance events, resource competition (presence of primates) and differential dispersal power among species. Depending on the context and age of island formation all these processes could have different levels of importance. Specific questions regarding these processes requires a previous knowledge of the taxonomic composition of these communities.