Investigating an Unknown Biodiversity: Evidence of Distinct Lineages of the Endemic Chola Guitarfish Pseudobatos percellens Walbaum, 1792 in the Western Atlantic Ocean

Abstract

Anthropogenic actions have affected marine species for a long time, through overexploitation of natural stocks and habitat degradation, influencing the life strategies of several taxa, especially rays and sharks, which have suffered significant population declines in recent years. Therefore, conservation actions and stock management have become paramount. In this regard, chola guitarfish, Pseudobatos percellens, distributed throughout the Brazilian coast, is often commercially fished by local artisanal fleets or as by-catch in shrimp trawl fisheries. Therefore, this study aimed to understand the genetic diversity of P. percellens throughout the Brazilian coast, using single nucleotide polymorphisms (SNPs). Genetic analyses employing 3329 SNPs revealed a hidden biodiversity within P. percellens, with at least one lineage occurring in the Northern and Northeastern regions and another distributed in the Southeastern/Southern Brazilian coast, with high genetic differentiation between them. However, the Discriminant Analysis of Principal Components (DAPC) indicated the presence of in fact three lineages distributed in these regions that must still be better investigated. Therefore, to ensure adequate conservation of chola guitarfish biodiversity, populations must be managed separately along the Brazilian coast. Furthermore, the need for a taxonomic review for this group is noted.

Population structure of the critically endangered Brazilian guitarfish Pseudobatos horkelii (Rhinobatidae) revealed by double‐digest restriction site‐associated DNA sequencing

“…Despite the expectation of low genetic diversity, the genetic diversity values observed for P. horkelii based on SNP markers were higher (mean H O = 0.22) compared with the less threatened elasmobranch species Chiloscyllium punctatum (mean H O = 0.09) (Fahmi et al, 2021), but were similar to some populations from a threatened congener species Pseudobatos percellens (Cruz et al, 2023). This is also analogous to the status of sawfishes has also been observed in Pristis pectinata in a study employing microsatellite markers in an area with similar distance range as in the present study (Chapman et al, 2011).…”