Taxonomia de Dasythemis (Karsch, 1889) (Odonata: Libellulidae)

Abstract

Among the insects of the order Odonata, the suborder Anisoptera stands out for its cosmopolitan distribution and high dispersal capacity. This is made easier by their broad, non-petiolate wings, with a developed anal area on the hind wings. When perched, individuals of this suborder are recognizable by keeping their wings open. They also have a robust body and high flight capacity. Anisoptera is currently divided into five superfamilies: Aeshnoidea, Petaluroidea, Gomphoidea, Cordulegastroidea and Libelluloidea. Libelluloidea includes the most diverse and ubiquitous family, Libellulidae, which includes the target group of this study. Dasythemis is endemic to South America and has a complex taxonomic history. The lack of recent studies highlights significant gaps in understanding the diversity, taxonomy and geographical distribution of species in this group. Considering this, the present research aimed to fill these gaps through a detailed review of the literature, analysis of material collected from different regions, and a comprehensive study of morphology. To achieve this, 168 specimens from 11 institutions in three South American countries - Argentina, Brazil and Peru - were analyzed. The specimens were identified based on general identification keys and original descriptive works. For the redescriptions, the wing terminologies followed the proposal by Riek and Kukalová-Peck (1984), with modifications by Bechly (1996). The nomenclature of other morphological structures was based on Asahina (1945) and Garrison et al. (2006). Photographs were taken using a stereomicroscope equipped with a camera and illuminated by an LED dome for uniform lighting. As a result, all species and one subspecies were redescribed in a standardized manner, employing features used in more recent studies on the group. All species were illustrated with photographs; additionally, the vesica spermalis was examined using Scanning Electron Microscopy (SEM), illustrating this structure in detail for the first time.