Systematics of Neotropical Oecetis McLachlan, 1877 (Trichoptera: Leptoceridae): When the taxonomy and phylogeny meet

Abstract

The worldwide distributed genus Oecetis currently contains around 550 valid species, 73 of them recorded in the Neotropical region. The genus is characterized by adults bearing long and stout maxillary palps and an unbranched M-vein on forewings. More than 50% of the Neotropical species of Oecetis was described in the past 20 years. However, those descriptions were authored by different specialists, not following a standard layout and there is no published phylogenetic hypothesis for the genus diversity in a cladistics framework. In this study we propose a phylogenetic hypothesis for the Neotropical species of Oecetis based on morphological characters and review most of its diversity taxonomically, offering a dichotomous key for specimen identification and new country records in the Neotropical region. The species of Oecetis occurring in the Neotropics do not form a monophyletic group, meaning that its history is more intricate than a single origin would assume. Most of the species-groups addressed in the taxonomical literature are recovered (such as the Oecetis punctata- and Oecetis inconspicua-groups), the Oecetis punctipennis-group is inferred as the sister group of the remaining Neotropical Oecetis, and we propose a new species-group: the Oecetis pratti-group.