Fish diversity of the largest deltaic formation in the Americas - a description of the fish fauna of the Parnaíba Delta using DNA Barcoding

Abstract

Deltas are dynamic and productive systems of enormous ecological significance, encompassing unique and biologically diverse wetland habitats. Here, we present the first data on the molecular diversity of the fish fauna of the Parnaíba Delta, the largest deltaic formation of the Americas. Partial sequences (626 bp) of the mitochondrial COI gene (Cytochrome c oxidase subunit I) were used to barcode 402 individuals, representing 128 species, belonging to 98 genera, 57 families, 17 orders and two classes. The most abundant orders were the Perciformes, Siluriformes, Gobiiformes, and Pleuronectiformes. The Neighbor-Joining (NJ), Bayesian Inference (BI), and BIN analyses produced 103 molecular clusters, while the Automatic Barcode Gap Discovery (ABGD) and Maximum Likelihood (ML) approaches revealed 102 clusters. The mean conspecific, congeneric and confamilial genetic distances were 0.33%, 14.37%, and 18.60%, respectively. Intraspecific divergence ranged from 0.0% to 1.4%, and all species presented barcode gaps, with the exception of two clusters of Cathorops spixii (OTU 96 and OTU 103), which were separated by a low interspecific distance (1.2%), which overlaps the maximum intraspecific genetic distance (1.4%). The barcode data provide new insights into the fish diversity of the Parnaíba Delta, which will be important for the development of further research on this fauna.

DNA Barcoding of Fish in Mischief Reef—Fish Diversity of a Reef Fish Community From Nansha Islands

“…Previous studies have attempted to delineate species boundaries based on DNA barcode data (Meier et al, 2008;Bhattacharjee et al, 2012), with Hebert proposing a COI sequence threshold for conspecific and congeneric divergence-the 10 × rule-where a 10-fold difference in mean intraspecific variation was adequate to draw boundaries between species (Hebert et al, 2004). Our findings do not support this because we report much lower intergeneric genetic distance (9.59%) between Diagramma picta and Plectorhinchus chaetodonoides, but higher intrageneric genetic distances between taxa such as Epinephelus (9.81%), Parupeneus (9.88%), Lethrinus (10.33%), Acanthurus (10.41%), and Chaetodon (13.68%), consistent with Barman et al (2018) and Guimarães-Costa et al (2019). Because frequent overlap between intra-and interspecific divergence was also reported in earlier studies, it is difficult to generalize a threshold for genus-or higherlevel resolution.…”

A shot in the dark for conservation: Evidence of illegal commerce in endemic and threatened species of elasmobranch at a public fish market in southern Brazil

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Assessing fish diversity of Merbok Estuary and adjacent marine waters by DNA taxonomy: towards building comprehensive DNA barcode reference library

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