Revisão taxonômica de dois grupos de espécies do gênero Dichotomius (Luederwaldtinia) Martínez, 1951 (Coleoptera: Scarabaeidae: Scarabaeinae)

Abstract

The genus Dichotomius is widely distributed in American continent and is found in many environments in Brazil requiring urgent taxonomic revision. This genus has about 170 species described and divided into four sub-genres among which is the subgenre Luederwaldtinia which is characterized by the following combination of characters: lateral border of the head rounded acute angle at the junction-genal clypeus, clypeal teeth separated by emargination; hairiness metasternal generally abundant, last abdominal sternite of female never extended beyond the apex of the pygidium. This subgenre has 62 valid species divided into 13 groups of species, among which is the group crinicollis and the group assifer. The group crinicollis is characterized by the following combination of characters: the long, thick and curved on the side of the pronotum, elytra strongly striated; pronotum and punctuated with rough depression in the anterior portion and the presence of a tooth at the junction of clypeus and gena. The group assifer is characterized by the following combination of characters: hipômero with anteromedial portion excavated and medially delimited by a brush with red, except for one species Dichotomius machadoi; males with a transverse carina on the head and pronotum with one or two gibbosities. The objective of this paper is to review the taxonomic group and the group crinicollis assifer. For taxonomic revision was made a comparative analysis of external morphology and internal (genitalia) following the procedures in traditional taxonomy. In this work the group crinicollis has nine valid species, two of which are new species. They are: D. crinicollis; D. semisquamosus; D. frimbriatus; D. micans, D. nobilis, D. bechynei; D. sexdentatus; D. sp. nov. 1, D. sp. nov 2. In group crinicollis three names are considered synonyms, one (D. inflaticollis) considered new synonymy. The group assifer has five valid species, two of them being new species: D. assifer; D. affinis, D. machadoi; D. sp. nov 3 and D. sp. nov 4.