Sistemática de Pilielmis Hinton, 1971 (Coleoptera: Elmidae)

Abstract

Elmidae Curtis is one the most diverse family of aquatic beetles, with more than 1500 valid species allocated among 148 genera in two subfamilies. In the Neotropical Region this family comprises 47 genera. One of them, Pilielmis, was described by Hinton in 1971, and currently is represented by seven species distributed in Brazil, Colombia, French Guiana, Peru, and Venezuela. Since the original description of this genus and of the first six species, only one new species has been described. Furthermore, many structures were not illustrated and described in the original descriptions (e.g., characters of the female terminalia and mouth parts). The objective of this study was to perform a systematic analysis of Pilielmis to increase taxonomic and morphological knowledge about the species in this genus and to access their relationships. Approximately 1665 specimens were analyzed, including the type-specimens of the previously described species. For morphological analysis, when needed, the dissected structures were cleared and mounted between slide and coverslip, using jelly-glycerin as the mounting medium. Phylogenetic analysis was based on 43 morphological characters of adults, which were evaluated by the Fitch parsimony method in TNT software using two approaches: under equal weights and implied weighting. The analysis under the implied-weighting approach resulted in a single most-parsimonious tree. In this hypothesis, Pilielmis was recovered as a monophyletic group and the species were clustered into three clades. Pilielmis was recovered as a sister-group of Hexacylloepus Hinton. All known species in this genus were redescribed, three new species were described, and the geographical distributions of the genus and the species have been extended. Detailed descriptions, including illustrations of structures not usually analyzed in taxonomic studies of the Elmidae, diagnoses, taxonomic comments, and keys for identification of the adults of Pilielmis are also presented. These results will contribute to future systematic studies of the family and will expand knowledge about the biodiversity of aquatic insects in the Neotropical Region.