Frere et al., 2008:

"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.

Although sampling sites in eastern Australia (Queensland) and Western Australia are farther away from each other than eastern Australia is from Hong Kong, all Australian animals are nonetheless grouped together in a single, shallow clade."

Frere et al (2008) have provided evidence that populations in South Africa and China are more closely related to each other, and to the Atlantic S. teuszii, than they are to humpback dolphins from Australia. This indicates that taxonomies that consider humpback dolphins in China and Australia to be of the same species (S. chinensis), whereas humpback dolphins in South Africa represent a different species (Sousa plumbea) clearly need revision.

"Although the present study is based on only a short mtDNA fragment, our findings are unequivocal. The three Indo-Pacific populations sampled clearly represent distinct evolutionary entities, with humpback dolphins in South Africa and Hong Kong more closely related to each other, and to the Atlantic S. teuszii, than to those in Australia. Australian humpback dolphins are highly divergent from those in nearby South-east Asia, and we suggest that they likely represent a distinct species. The recognition of the Australian Sousa as an evolutionarily significant unit (ESU; Moritz 1994), and potentially as a distinct species in its own right, has important implications for conservation and management.

Humpback dolphins are considered a priority for management and research by the Great Barrier Reef Marine Park (Anon. 2000), but existing protected areas in north-east Queensland may not include the most critical habitats for them (Parra et al. 2006b). Further, their shallow water distribution, the small size of some populations (100–200 individuals), and their strong site fidelity make them particularly vulnerable to local extinction (Parra 2005; Parra et al. 2006a). There are no overall abundance estimates for this species in Australian waters.

Multiple independent lines of evidence are generally required for the recognition of new species (Reeves et al. 2004). Further molecular and morphological work will therefore be required to confirm the species distinctiveness of Sousa in Australia, and determine the exact location of the species break between South-east Asian and Australian populations in the Indonesian archipelago."

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Citation and/or URL

Frere, C.H., Hale, P.T., Porter, L., Cockcroft, V.G. and Dalebout, M.L. 2008, Phylogenetic analysis of mtDNA sequences suggests revision of humpback dolphin (Sousa spp.) taxonomy is needed. Marine and Freshwater Research 59: 259-268.  © CSIRO 2008. CSIRO Publishing, Melbourne Australia. http://www.publish.csiro.au/nid/126/paper/MF07120.htm  

Spatial Coverage

Samples collected from Australia, Hong Kong and South Africa 

Temporal Coverage

 Samples collected between 1989 and 2002

Update Frequency

Not applicable 

Other Information

 None