First molecular approach to the octopus fauna from the southern Caribbean.

Abstract

The octopus fauna from the southern Caribbean is an understudied field. However, recent taxonomic work in the Colombian Caribbean has led to the discovery of several new species in the family Octopodidae. To provide molecular evidence for recent descriptions in the area (i.e., Octopus taganga, O. tayrona and Macrotritopus beatrixi) and contribute to the systematics of the family, we reconstructed the first molecular phylogenies of the family including Colombian Caribbean octopus species. Using cytochrome c oxidase subunit I and rhodopsin sequences from specimens collected in three sites (Santa Marta, Old Providence and San Andrés Islands) we inferred maximum-likelihood trees and delimited species with PTP. Our mitochondrial analysis supported the monophyly of species found in the area (i.e., O. taganga, O. hummelincki and O. briareus). The genetic distinction of the species O. tayrona and O. insularis was not resolved, as these were found in one clade together with Caribbean O. vulgaris and O. aff. tayrona species (O. spB) and delimited as a single species. Additionally, our results suggest a distant relationship of the Type I O. vulgaris group (Caribbean region) from the other forms of the species complex (Old World and Brazil). Lastly, the third newly described species M. beatrixi emerged as an independent lineage and was delimited as a single species. However, its relationship to other species of its genus remains unknown due to the lack of sequences in databases. Altogether, our molecular approach to the octopus fauna from the southern Caribbean adds on information to the relationship of Octopodidae species world-wide by providing sequences from recently described species from an understudied region. Further studies employing higher taxon sampling and more molecular information are needed to fill taxonomic gaps in the area and account for single-locus resolution on the systematics of this group.