Andesiops peruvianus (Ephemeroptera: Baetidae): a species complex based on molecular markers and morphology

Andesiops peruvianus is widely distributed in the Andean region and has been preliminarily used as a bioindicator of good water quality. Given the morphological variations that are reported for the species, this study aimed to address whether such morphological variability in nymphs captured in tributaries of the Upper Chinchiná River Basin, Caldas-Colombia, could be connected to genetic differences, suggesting the existence of hidden, hitherto unknown taxonomic diversity. The morphological evaluation allowed confirming the presence of 73 females and 83 males belonging to what can be considered A. peruvianus sensu lato. However, Automatic Barcode Gap Discovery and Poisson Tree Processes modeling identified four different taxonomic units. The genetic distances found for specimens of A. peruvianus were higher than expected for conspecific organisms, and DNA analyses allowed to separate A. peruvianus into taxonomic units, which were further supported by morphological characters (shape and size of the abdominal gills and number of denticles of the tarsal claws). The results of this study show that A. peruvianus represents a species complex, with four putative species inferred, contributing to the growing knowledge of the existence of pseudocryptic species. These new findings could influence the conservation status of these rivers.