Sistemática de leporinus (characiformes, anostomidae) a partir de ferramentas moleculares e morfológica

Abstract

The genus Leporinus includes around 80 valid species, grouping the largest number of species within the Characiformes order and being the most diverse within the Anostomidae family. The species are widely distributed in river basins in the Neotropical region, but it is a fact that it is difficult to understand the biodiversity of the genus Leporinus, i.e. the specific limit, because the morphological patterns are very similar between the species of this genus, as are the phenotypic characteristics observed in juvenile and adult individuals. This study used mitochondrial and nuclear genome sequences and morphological data to identify and provide the kinship relationships of the Leporinus species, thus contributing information that should be used in the species' management and conservation plans. The integrative study using morphological and molecular data made it possible to record Megaleporinus macrocephalus in the Maranhão river basins, representing an important extension of its distribution, which is now confirmed in the Itapecuru and Mearim river basins. The analysis of 157 Leporinus COI gene sequences from the Itapecuru, Mearim, Turiacu, Pericumã, Periá, Preguicas, Parnaíba and Tocantins river basins identified L. maculatus, L. unitaeniatus, L. affinis and L. piau (from the Parnaíba river) as distinct groupings corroborated by species delimitation methods, which revealed the presence of four distinct MOTUs corresponding to each of these species. The bPTP method restricted L. venerei to a single MOTU, pointing to the first occurrence of this species in rivers in Maranhão. There was also evidence of the separation of L. cf. friderici into two clades and the subsequent formation of different MOTUs, which is therefore consistent with the polyphyly of this species indicating the existence of cryptic diversity, as well as the configuration of L. cf. friderici and L. piau into two clades supporting the conclusion that the specimens of L. piau from Maranhão were misidentified. In the investigation of cryptic diversity in L. piau from the Maranhão and Piauí river basins, using mitochondrial and nuclear markers, two well-supported groups were observed, in which specimens from the Itapecuru, Mearim, Turiaçu and Pericumã rivers were assigned to an unnamed clade, representing relatively ancient diversification and probably hiding cryptic diversity. The second group included specimens from the Parnaíba and Mearim rivers, called L. cf. friderici sensu stricto, a group that diversified relatively recently and is more closely related to L. friderici from the type locality. The results confirmed the existence of a complex scenario of cryptic diversity in the Leporinus genus and the taxonomic inconsistencies found in this group of fish.