Phylogenetic analysis of mtDNA sequences suggests revision of humpback dolphin (Sousa spp.) taxonomy is needed
Céline H. Frère A E , Peter T. Hale B , Lindsay Porter C , Victor G. Cockcroft D and Merel L. Dalebout A
+ Author Affiliations
- Author Affiliations
A School of Biological, Earth and Ecological Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
B School of Integrative Biology, University of Queensland, Brisbane, Qld 4072, Australia.
C Worldwide Fund for Nature, 1 Tramway Path, Central, Hong Kong.
D Centre for Dolphin Studies, PO Box 1856, Plettenberg Bay, South Africa 6600.
E Corresponding author. Email: c.frere@uq.edu.au
Marine and Freshwater Research 59(3) 259-268 https://doi.org/10.1071/MF07120
Submitted: 25 June 2007 Accepted: 3 March 2008 Published: 30 April 2008
Abstract
Humpback dolphins (Sousa spp.) have a wide distribution in the tropical Atlantic and Indo-Pacific Oceans and a confused taxonomy. Morphological assessments suggest three species groupings – Sousa teuszii (eastern Atlantic), Sousa plumbea (western Indo-Pacific), and Sousa chinensis (eastern Indo-Pacific) – but most taxonomies recognise only two species – S. chinensis (Indo-Pacific), and S. teuszii (Atlantic). To investigate phylogenetic relationships, mitochondrial DNA control region sequences (338 base pairs) from 72 Sousa representing three populations in the Indo-Pacific (South Africa: S. plumbea, n = 23; China: S. chinensis, n = 19; and Australia: S. chinensis, n = 28), and S. teuszii in the Atlantic (Mauritania, n = 2) were generated. All three Indo-Pacific populations formed robust, monophyletic clades with high bootstrap (BS) and Bayesian posterior probability (BPP) scores. Surprisingly, humpback dolphins from South Africa and China formed a strongly-supported clade with the Atlantic S. teuszii (BS 63%, BPP 0.92) to the exclusion of animals from Australia. Genetic divergence between animals from China and Australia (DA = 8.4% ± 2.47%) was greater than between China and South Africa (DA = 5.1% ± 1.80%). These results strongly suggest that Australian humpback dolphins are not S. chinensis but may represent a distinct species in their own right.
Additional keywords: Australia, Delphininae, Hong Kong, phylogeography, South Africa, speciation.
Acknowledgements
We would like to acknowledge the support and enthusiasm of Graham J. B. Ross throughout the study. For assistance with specimen collection, we thank the Queensland National Parks and Wildlife Service, along with Natal Sharks Board for the South African samples. The samples from Hong Kong were collected as part of a strandings program funded by the Agriculture, Fisheries and Conservation Department of the Hong Kong SAR Government. We thank Randall R. Reeves, Guido J. Parra, and William F. Perrin for their constructive feedback on earlier versions of the manuscript. M.L.D. is supported by a UNSW Vice-Chancellor’s Postdoctoral Fellowship. The present study was funded by the Department of Environment and Heritage and formed part of CHF’s BSc Honours research at the University of Queensland.
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