DNA barcoding and phylogeography of the Hoplias malabaricus species complex

Abstract

Hoplias malabaricus (Bloch, 1794) is a carnivorous fish species widely distributed from northern to southern South America. This taxon is believed to be a good model for the investigation of biogeographic events that shape the ichthyofauna evolution in the Neotropical freshwater systems. However, many studies have revealed that H. malabaricus hides a species complex that hampers its taxonomic identity and limit its practical value for evolutionary and biogeographic studies. In this paper, we used the mitochondrial gene cytochrome c oxidase subunit I (COI) to delimit cryptic species and explore the phylogeography of H. malabaricus sensu stricto. We found genetic evidence for putative new species in the genus Hoplias and showed that H. malabaricus (Bloch, 1794) is a major clade assigned to barcode index number (BIN) BOLD:ABZ3047. This species is structured in six subpopulations differentiated by high Fst values and restricts gene flow. The subpopulations of the São Francisco/East Atlantic/Eastern Northeast Atlantic/Parnaíba/Itapecuru River basins and Tapajós River Basin were the most differentiated and showed demographic fluctuations. The present distributional pattern is most likely explained through a scenario from the Pleistocene.

Phylogeography of Sarmarutilus rubilio (Cypriniformes: Leuciscidae): Complex Genetic Structure, Clues to a New Cryptic Species and Further Insights into Roaches Phylogeny

“…According to what was observed in 1088 fish species [ 80 ], sequences with a divergence of greater than 2% or 3% likely belong to different species (with a probability greater than 95%). This COI divergence threshold was generally confirmed with an analysis implementing several methods for species delimitations in fishes and allowed for the identification of cryptic species [ 81 , 82 , 83 ] even in Leuciscidae [ 84 ]; furthermore, 2–3% divergence was observed between many Leucos and Rutilus taxa whose status as good species is not debated. Although our nuclear dataset is limited, a substantial divergence (almost 4%) and a slight difference in length were observed between Cyfun P sequences exclusive to VAR sites and mostly present in specimens belonging to mitochondrial lineage C, and those widespread across S. rubilio populations.…”

A new species of Rhacophorus (Anura, Rhacophoridae) from Guangxi, China

“…Only by making a clear and scientific distinction between species can we further study the interspecific relationship, biodiversity and evolution of species. With the maturity of research technology, especially the rapid development of molecular systematics, more and more species complexes have been deeply studied ( Villalobos-Guerrero 2019 ; Amorim et al 2022 ; Guimarães et al 2022 ;), which shows that there may be some mistakes in the current species classification, and there are more cryptic species waiting to be discovered. The study of cryptic species and complexes will have a far-reaching impact on evolutionary theory, biogeography and conservation planning, which needs attention ( Bickford et al 2007 ).…”

New records of native and introduced fish species in a river basin of Western Ecuador, the Chocó-Darien Ecoregion, using DNA barcoding

“…Additionally, because Hoplias microlepis from Ecuador places separately from H. microlepis (samples from Panama) and H. malabaricus (samples from Brazil) in the trees (S3 and S4 Figs in S1 File), this highlights the need to perform deeper genetic and morphological studies with the Ecuadorian species from different western basins. This is particularly necessary for Hoplias species given the known species complex of Hoplias malabaricus harboring several subclades (among them H. microlepis) [20,64], the disjoint distribution of H. microlepis between Pa ´nama and Ecuador [47] and the proclivity of Hoplias microlepis to quickly accumulate genetic differences between populations [29].…”