DNA sequence data analysis supports the taxonomic status of Eucinostomus dowii within the genus (Perciformes: Gerreidae)

Since its description in 1855, the specific composition of the gerreid genus Eucinostomus Baird has been controversial. At present, there are different views concerning the occurrence of Eucinostomus species in the Eastern Pacific. For instance, the Dow’s mojarra Eucinostomus dowii (Gill, 1863) has been considered by some authors as a synonym of E. argenteus Baird and Girard, 1855. The silver mojarra E. argenteus is a typical inhabitant of coastal systems along the Atlantic Ocean, and this species has also been mistakenly identified as the dark-spot mojarra E. entomelas Zahuranec in Yáñez-Arancibia, 1980, another Eastern Pacific species. In this study, the DNA fragments from mitochondrial (COI, 12SrRNA and 16SrRNA) and nuclear (RAG1) genes were sequenced for the three gerreid species including Eucinostomus dowii, E. argenteus, and E. entomelas. The analysis of DNA sequence variation allowed identification of a significant genetic distance among these fishes, and support that the three taxa are not synonymous to each other and should be considered different evolutionary entities.