Species delimitation in Neotropical fishes of the genus Characidium (Teleostei, Characiformes)

Abstract

Neotropical darters of the genus Characidium have a complex systematic history with several examples of sympatry throughout their distribution range in Neotropical freshwaters. Although various species within the genus have been used as models to investigate chromosomal evolution and biogeography, species boundaries and relationships still remain uncertain. Here, we use mitochondrial DNA sequences to perform species delimitation analyses within Characidium and test previous hypotheses of species richness within the Characidium zebra complex and among sympatric morphotypes of C. alipioi. Results indicate high genetic distances within tested species complexes and revealed the presence of strongly supported lineages such as the large C. lauroi group from southeastern Brazil. This suggests that the evolutionary history of these groups may be correlated with biogeographic history. Analyses also reveal that three geographically isolated populations of C. zebra represent a single species, leading us to reject prior hypothesis of multiple species. Species delimitation using mitochondrial data strongly supports the presence of two sympatric species within C. alipioi in southeastern Brazil despite limited morphological variation and conserved chromosomal patterns. These results provide a framework to further the study of systematics and evolution within Characidium.

DNA Barcoding Reveals High Levels of Divergence among Mitochondrial Lineages of Brycon (Characiformes, Bryconidae)

“…amazonicus are represented by two or more MOTUs, separated by a high degree of genetic diversity. A number of previous studies of genetic species delimitation in Neotropical fish have produced similar findings, in which the nominal species identified on the basis of morphological characteristics were recovered as distinct molecular taxonomic units [13,16,38,39,40,41,42,43,44,45].…”

“…The GMYC, ABGD, BI, and ML approaches have been applied increasingly for the delimitation of species, although some studies [44,45,47,48] have recovered a larger number of lineages using the GMYC approach in comparison with the other methods. The results of the present study contrasted with this pattern, however, given that the GMYC analysis did not separate B. pesu lineages 3 and 4 into distinct MOTUs, even though they were separated by genetic distances of over 1.82% (3.2%).…”

A new species of Characidium (Characiformes: Crenuchidae) from coastal basins in the Atlantic Rainforest of eastern Brazil, with phylogenetic and phylogeographic insights into the Characidium alipioi species group

“…Although a formal phylogenetic analysis was not carried out herein, the combination of characteristics that include the pigmentation pattern, unscaled isthmus but scaled chest, and long distance from the anus to the anal-fin origin with little imbricated, aligned scales, might diagnose a putative species clade that we call the C. alipioi species group. The number of species of the C. alipioi group may increase in the future, because recent studies (Serrano et al, 2019) have demonstrated the presence of cryptic species in the Paraíba do Sul drainage that are morphologically similar 9 e180121[9] Fig. 2.…”

Checklist and key for the identification of fish fauna of the Uberaba River, Upper Paraná River system, Brazil

“…Characidium zebra was described in tributaries of the Branco River (Negro River system) in the Amazon. Recent evidence suggests that C. zebra populations in the San Francisco and Paraná rivers correspond to the same species (Serrano et al 2018) distinct from the C. zebra populations of the Amazon drainage.…”