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The Daggernose Shark Isogomphodon oxyrhynchus is an endemic species of the northern coast of South America distributed from Trinidad and Tobago to Brazil's Amazon Coast. Due to increasing fishing efforts and its limited distribution range, the Daggernose Shark is one of the most endangered shark species in the world. Further threats arise from mangrove deforestation, pollution, and aquaculture caused by increasing human populations in coastal areas. The Daggernose Shark is highly associated to the turbid waters influenced by the Amazon and Orinoco estuaries. Furthermore, its morphological features associated to adaptations to these environments such as an elongated rostrum, small eyes, and long pectoral fins make it one of the most iconic shark species in the world. Finally, we report the capture of a young‐of‐the‐year I. oxyrhynchus in a freshwater system in Northern Brazil—the first recorded in a non‐marine environment. [ABSTRACT FROM AUTHOR]

• Dasyatidae is the batoid family most commercialized in the Brazilian Amazon coast. • Bycatch and trade of highly endangered batoids are common practices. • Strong evidence of an undescribed and commercially exploited species of the genus Narcine. • Genetic structuring patterns indicate possible geographic and/or reproductive separations between populations of the same species. Overfishing can lead to stock collapses of both target and bycatch species. In some cases, unregulated fishing activities can even drive species towards extinction. Batoids comprise a significant portion of the bycatch of fisheries targeting teleost fishes. In Brazil, the Amazon coast is the second largest landing area in the country for these organisms. The present study aimed to identify batoid species captured and traded along the Brazilian Amazon coast, as well as to analyze the batoids species most commercialized in the region by using the cytochrome oxidase c subunit 1 (COI) mitochondrial gene. In total, 118 samples were collected and nine species identified. Dasyatidae was the most abundant family (two genera, three species, and 52 individuals), followed by Aetobatidae (one genus and one species), Rhinopteridae (one genus, two species), and Narcinidae (one genus, one species), each with 14 individuals. Finally, Gymnuridae and Pristidae were represented by one genus, one species and 12 individuals each. Threatened species, such as Pristis pristis and Rhinoptera brasiliensis, were found to be commonly traded in the fish markets. Results also pointed the presence of a third and undescribed Narcine species. Finally, genetic differences between populations of the same species were found for Hypanus guttatus , Aetobatus narinari , and Rhinoptera bonasus - indicating possible geographic and/or reproductive separations. Therefore, we reinforce the need of forensics research to incorporate DNA-based evidence. This information could support improvements on management and law enforcement of batoid fisheries and trade in Brazil. [ABSTRACT FROM AUTHOR]