Ecological divergence and speciation in common bottlenose dolphins in the Western South Atlantic

Costa, A. P.B. , Fruet, P. F., Secchi, E. R., Daura-Jorge, F. G., Simões-Lopes, P. C., Di Tullio, J. C. and Rosel, P. E. (2021) Ecological divergence and speciation in common bottlenose dolphins in the Western South Atlantic. Journal of Evolutionary Biology, 34(1), pp. 16-32. (doi: 10.1111/jeb.13575) (PMID:31808214)

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Abstract

Coastal and offshore ecotypes of common bottlenose dolphins have been recognized in the western South Atlantic, and it is possible that trophic niche divergence associated with social interactions is leading them to genetic and phenotypic differentiation. The significant morphological differentiation observed between these ecotypes suggests they represent two different subspecies. However, there is still a need to investigate whether there is congruence between morphological and genetic data to rule out the possibility of ecophenotypic variation accompanied by gene flow. Mitochondrial DNA (mtDNA) control region sequence data and 10 microsatellite loci collected from stranded and biopsied dolphins sampled in coastal and offshore waters of Brazil as well as 106 skulls for morphological analyses were used to determine whether the morphological differentiation was supported by genetic differentiation. There was congruence among the data sets, reinforcing the presence of two distinct ecotypes. The divergence may be relatively recent, however, given the moderate values of mtDNA nucleotide divergence (dA = 0.008), presence of one shared mtDNA haplotype and possibly low levels of gene flow (around 1% of migrants per generation). Results suggest the ecotypes may be in the process of speciation and reinforce they are best described as two different subspecies until the degree of nuclear genetic divergence is thoroughly evaluated: Tursiops truncatus gephyreus (coastal ecotype) and T. t. truncatus (offshore ecotype). The endemic distribution of T. t. gephyreus in the western South Atlantic and number of anthropogenic threats in the area reinforces the importance of protecting this ecotype and its habitat.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Borges De Camargo Costa, Dr Ana
Authors: Costa, A. P.B., Fruet, P. F., Secchi, E. R., Daura-Jorge, F. G., Simões-Lopes, P. C., Di Tullio, J. C., and Rosel, P. E.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Journal of Evolutionary Biology
Publisher:Wiley
ISSN:1010-061X
ISSN (Online):1420-9101
Published Online:05 December 2019

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