Morfologia de Symphypleona (Hexapoda, Collembola): nova abordagem e sua aplicação em estudos taxonômicos e filogenéticos em Sminthuroidea

Abstract

Collembola comprises a monophyletic group of small, abundant arthropods with a global distribution. It is a group of ancient origin in the Athropoda lineage, dating from the Silurian. It has approximately 9,200 species described, but recent estimates suggest that the actual number of species on the planet may be close to 500,000. Such evidence reinforces the importance of research in the group. Among its most well-known representatives, the order Symphypleona are globular Collembola. For this group, there are currently several options of methodological approaches applicable to the morphological study. However, even with this methodological advance and availability of information, it is possible to observe that today there is a lack of consensus among authors dedicated to taxonomy and systematics in Symphypleona. This fact seems to exist due to different modes of interpretation and understanding of chaetotaxical study methodologies and even other general structures. This work aims to address the methodological consensus problem in Symphypleona. The present study, in total, shows a synthesis of terms and approaches of morphological study with tests and exercise in taxonomic and phylogenetic practices. The first part provides a new synthesis of the terminologies used in general morphology, an explanation of complex chaetotaxy methods and adaptations that make them more viable for use. In this section a distinction is made between classical and chaetotaxy structures. The second part presents an application of this synthesis in a taxonomic study for Prorastriopes (Sminthuroidea: Bourletiellidae). Eight species, from eight points on the American continent, are described. In this section, the chatotaxy proved to be an essential tool in differentiating very similar species in terms of other characteristics. Finally, the last part presents an exercise in the elaboration of a matrix with general and chaetotaxy morphological characters, as well as a preliminary analysis for species of Sminthuroidea, one of the five superfamilies in Symphypleona. With these results is expected to provide guidance in the phylogenetic study of both Sminthuroidea and Symphypleona in general.