Taxonomia iterativa de crustáceos troglóbios do gênero Potiberaba Fišer, Zagmajster & Ferreira 2013 (Crustacea: Amphipoda) na Caatinga

Abstract

Underground systems can be found in several mineral formations, sheltering a fauna with different life strategies, which together can use the underground environment permanently or temporarily. Among these inhabitants, the troglobites stand out, a group that includes organisms that present a series of ecological, physiological, morphological and behavioral adaptations associated with the subterranean environment. In Brazil, the troglobite fauna has been described with greater intensity in the last two decades, with the prospecting of new locations and the integration of different analytical tools. Despite this, the South and Southeast regions still stand out to the detriment of the others, concentrating most of the taxonomic, ecological and genetic studies of troglobite organisms. However, the Northeast, especially the state of Rio Grande do Norte (RN), has been standing out in the knowledge of this fauna, with the discovery of new species of troglobite invertebrates, such as crustaceans, flatworms and insects. Among the new organisms described in the RN is the genus of amphipods Potiberaba, monotypic and endemic to caves in the region, which for seven years presented a distribution restricted to the type locality. After new expeditions, specimens were recorded in eleven more locations, and whose molecular data indicated possible new species in the region's caves. Until then, the hypothesis was based only on delimitations using a mitochondrial marker. Thus, through an integrated approach between molecular (including nuclear markers) and morphological tools, the study proposed to evaluate the convergence between the different information to support the hypothesis of a species complex, as well as to identify morphological characters capable of distinguishing them, and at the end, propose the description of the new species of Potiberaba. Through an iterative approach between morphological information and molecular markers (cox1 and 28S), the study proposes the existence of five allopatric species, of which four have a restricted distribution, with low genetic and morphological diversity, while P. porakuara is widely found in the south of the Jandaíra Formation. The study also indicated that in addition to genetic divergences, the lineages can be identified through morphological characters with a high accuracy rate, showing that the species richness of this formation is underestimated.