Revealing Hidden Diversity of the Underestimated Neotropical Ichthyofauna: DNA Barcoding in the Recently Described Genus Megaleporinus (Characiformes: Anostomidae)

Abstract

Molecular studies have improved our knowledge on the neotropical ichthyofauna. DNA barcoding has successfully been used in fish species identification and in detecting cryptic diversity. Megaleporinus (Anostomidae) is a recently described freshwater fish genus within which taxonomic uncertainties remain. Here we assessed all nominal species of this genus using a DNA barcode approach (Cytochrome Oxidase subunit I) with a broad sampling to generate a reference library, characterize new molecular lineages, and test the hypothesis that some of the nominal species represent species complexes. The analyses identified 16 (ABGD and BIN) to 18 (ABGD, GMYC, and PTP) different molecular operational taxonomic units (MOTUs) within the 10 studied nominal species, indicating cryptic biodiversity and potential candidate species. Only Megaleporinus brinco, Megaleporinus garmani, and Megaleporinus elongatus showed correspondence between nominal species and MOTUs. Within six nominal species, a subdivision in two MOTUs was found, while Megaleporinus obtusidens was divided in three MOTUs, suggesting that DNA barcode is a very useful approach to identify the molecular lineages of Megaleporinus, even in the case of recent divergence (< 0.5 Ma). Our results thus provided molecular findings that can be used along with morphological traits to better define each species, including candidate new species. This is the most complete analysis of DNA barcode in this recently described genus, and considering its economic value, a precise species identification is quite desirable and fundamental for conservation of the whole biodiversity of this fish.

Updated checklist and DNA barcode‐based species delimitations reveal taxonomic uncertainties among freshwater fishes from the mid‐north‐eastern Caatinga ecoregion, north‐eastern Brazil

“…, ; Ramirez et al . , ). Despite working as a useful starting point to identify molecular operational taxonomic units (mOTU), single‐locus species delimitations have their constraints ( e.g.…”

“…, ; Ramirez et al . , ; Ward et al . , ) highlighting groups that require taxonomic revision (Armstrong & Ball, ; Díaz et al .…”

“…DNA barcodes have been especially useful in historically neglected geographical regions (Hubert et al, 2008;Ward et al, 2005). Indeed, this method is frequently used to estimate the inter and intraspecific diversity of freshwater fishes around the world (Carvalho et al, 2011;Díaz et al, 2016;Hubert et al, 2008;Pereira et al, 2011;Ramirez et al, 2017;Ward et al, 2005) highlighting groups that require taxonomic revision (Armstrong & Ball, 2005;Díaz et al, 2016;Hajibabaei et al, 2007).…”

“…DNA barcodes and other methods of single-locus species delimitation, have been largely used as a tool for species identification (Hajibabaei et al, 2007;Ramirez et al, 2017). Despite working as a useful starting point to identify molecular operational taxonomic units (mOTU), single-locus species delimitations have their constraints (e.g.…”

Mitochondrial divergence suggests unexpected high species diversity in the opsariichthine fishes (Teleostei: Cyprinidae) and the revalidation of Opsariichthys macrolepis

“…Molecular studies have been crucial to improve our knowledge on the ichthyofauna, and DNA barcoding has been successfully used in fish species identification and in detecting species of taxonomic concerns or cryptic diversity (Gomes, Pessali, Sales, Pompeu, & Carvalho, 2015;Pereira, Hanner, Foresti, & Oliveira, 2013). For example, Ramirez et al (2017) using a DNA barcoding approach detected hidden biodiversity within a recently described freshwater fish genus Megaleporinus and identified 16-18 different molecular operational taxonomic units (MOTUs) within each of the 10 studied nominal species. For the genus Salminus, which was once migratory fish and top predator distributed throughout South America major hydrographic basins, Machado, Ishizuka, Freitas, Valiati, and Galetti (2016) The Cyprinidae (cyprinids) represent one of the most diverse freshwater fish groups and are the major components of the primary freshwater fish fauna in Africa, Eurasia, and North America, comprising more than 367 genera and 3,006 species (Nelson, Grande, & Wilson, 2016).…”