Molecular taxonomy and population structure of the rough-toothed dolphinSteno bredanensis(Cetartiodactyla: Delphinidae)

Abstract

Several delphinid species have shown genetic population structure, both between and within ocean basins. We investigated genetic differentiation in the rough-toothed dolphin, Steno bredanensis, using mitochondrial control region sequences from several localities worldwide (N = 112). Preliminary analyses indicated high levels of genetic differentiation between the Atlantic and Pacific/Indian Oceans, which were further investigated using complete cytochrome b sequences and mitogenomes. Phylogenetic analyses were inconclusive about the existence of cryptic speciation in the genus Steno. Notwithstanding this result, analysis of molecular variance and Φ-statistics analyses revealed strong population differentiation not only between the Atlantic and Pacific, but also within the Atlantic, where three populations were detected: Caribbean, southeastern Brazil, and southern Brazil. We propose that these populations be considered management units for conservation purposes. Our results provide the first perspective on the worldwide genetic differentiation of S. bredanensis.

Rough-toothed dolphins (Cetartiodactyla: Delphinidae) habitat use in coastal urban waters of the South-western Atlantic

“…Our results may contribute towards forming a benchmark for further studies in this region, which are fundamental to fill gaps in our understanding of this species throughout its distribution. Within the Atlantic Ocean basin three populations were detected (southern, south-eastern Brazil and Caribbean), and are considered as population management units for conservation purposes (Da Silva et al ., 2015).…”

Seascape Genetics of the Atlantic Spotted Dolphin (Stenella frontalis) Based on Mitochondrial DNA

“…Other delphinids have also shown a similar pattern of isolation in the WSA, such as the clymene dolphin (Stenella clymene) (Nara et al 2017), Delphinus sp. (Amaral et al 2012b), the Guiana dolphin (Sotalia guianensis) (Caballero et al 2018) and the rough-toothed dolphin (Steno bredanensis) (da Silva et al 2015). In some cases, as with the Lahille bottlenose dolphin (Tursiops gephyreus), the differences were sufficient to lead some authors to propose a different species (Wickert et al 2016;Holh et al 2020).…”

Shallow‐water habitat use and population parameters of rough‐toothed dolphins, Steno bredanensis (G. Cuvier in Lesson, 1828) in southeastern Brazil

“…In the southwestern Atlantic Ocean (SWAO), studies on S. bredanensis have focused on bioacoustics (Lima et al, 2012), short-term behavioral aspects (Lodi, 1992), movements (Lodi et al, 2012;Santos et al, 2019), and interaction with fisheries (Monteiro-Neto et al, 2000). In Brazil, one study has investigated the population structure of S. bredanensis and documented the presence of a southeastern population (Silva et al, 2015). However, mark-recapture efforts with the sole aim of investigating nearshore occurrences are still scarce, and only a few records have been documented, which have suggested that individual site fidelity is linked to aspects of habitat use (Lodi & Maricato, 2020).…”

“…Because this species exhibits long‐distance movements along the southeastern Brazilian coast (Lodi et al, 2012; Santos et al, 2019), the studied individuals must have a broader home range than the study area, probably also including oceanic waters, as supported by observations in the outer continental shelf and oceanic waters 150–4,000 m deep in the SWAO (Bittencourt et al, 2018; Di Tullio et al, 2016). Broad home ranges were also implied by population genetics, which found no evidence of subdivision in southeastern Brazil (Silva et al, 2015).…”