Phylogeography of the electric rays of the family Narcinidae (Gill, 1862): systematic review and evidence of the dispersal routes to America.

The electric rays belonging family Narcinidae are a cosmopolitan group, which has come under increasing scrutiny in relation to the taxonomic composition of the family and its phylogenetic position within the order Torpediniformes. Phylogeographic inferences can provide important insights into the present-day distribution of the narcinid species, as well as the systematics of the group. In this context, the present study evaluates the evolutionary and biogeographic history of the family Narcinidae, inferring distribution patterns and the molecular systematics of these organisms based on the DNA barcode. The results of the analysis indicate that the electric rays originated in the Central Indo-Pacific realm, with all other dispersal events beginning from this region. Two different dispersal routes were observed for the American narcinids. The first route was from the Central Indo-Pacific realm to the Pacific Ocean and then the Caribbean Sea, prior to the closure of the Isthmus of Panama. The second route start on Central Indo-Pacific realm passed South Africa continent before crossing the Atlantic. The principal torpediniform lineages diversified between the end of the Cretaceous and the early Paleocene, with the present-day narcinid taxa arising and diversifying between 25 and 20 Mya. The present study confirms the lack of monophyly in the Narcinidae, validates the genus Narcinops, and restricts the occurrence of the genus Narcine to the coastal environments of the Americas, which emphasizes the need for the review and revalidation of the synonym Syrraxis for the narcinids of the Central/Western Indo-Pacific realm. This study also describes additional lineages for Narcine entemedor and Narcine maculata and validates the occurrence of three species (Narcinesp., Narcine brasiliensis, and Narcine bancroftii) in the Atlantic Ocean, based on the published data, and emphasizes the need for a definitive description of Narcine sp.