Revisão taxonômica de Pseudhomalopterus Pic, 1920 e Homalopterus Perty, 1832 (Coleoptera: Megalopodidae)

Abstract

Megalopodidae (Coleoptera) has 582 species allocated in 30 genera and 11 subgenera, belonging to the subfamilies Megalopodinae, Palophaginae, Zeugophorinae and Atelederinae. Among these Megalopodinae is the most diverse, recorded for tropical regions, mainly in Brazil, where 147 species belonging to 11 genera are registered. Although Brazil is the country with the greatest diversity of Megalopodidae little is known about the natural history of the species, and there is the need for taxonomic studies that contribute to a better genera and species definition, since many descriptions are very simplified and uninformative. Pseudhomalopterus Pic, 1920 is a Brazilian genus, monotypic, and was indicated by Pic as related to Homalopterus Perty, 1832. Homalopterus is also a Brazilian genus that has two species: H. tristis Perty, 1832 and H. heteroproctus Lacordaire 1945. Since their description, Pseudhomalopterus has not been studied in detail and there are doubts about the proximity between these genera. Thus, this study aimed to develop a taxonomic revision of Pseudhomalopterus and Homalopterus seeking to characterize them, establishing the limits of these genera more clearly. For this, the external morphology was meticulously studied from material deposited in national and international collections. Speciemens were dissected, and the genitalia was heated in KOH for tissue removal and better visualization of the structures. Pseudhomalopterus and Homalopterus share serrated antennae, presence of carina on the lateral margin of elytra and trapezoidal pronotum. Pseudhomalopteurs is distinguished mainly by presenting punctuated elytra with short, sparse and erect hairs, shiny integument, dilated metafemurs with presence of a spine on the ventral surface, antennae extending to the humeral callus, pronotum with two concavities, both black in color, female with converging vaginal palps crossing each other only at apex. Homalopterus has densely punctuated elytra, with fine and dense hairs, with velvety texture, slightly dilated metafemurs without spine on ventral surface, antennae extend beyond the humeral callus, presence of a yellowish marginal band on elytra, female with juxtaposed vaginal palps from base, crossing each other at the apex. This study give new informations that contribute to the genera diferentiation, mainly between Pseudhomalopterus and Homalopterus including information about the female genitalia.