Document presented to the 54th meeting of the International Whaling Commission
humpback dolphins, Indian Ocean, morphometrics, skull, taxonomy, whaling, Sousa chinensis, sousa plumbea, Sousa teuszii, Atlantic humpback dolphin
The author measured 181 skulls of humpback dolphins originating from throughout most of the range of Sousa. While patterns of skull variation appeared to be largely conservative, there was evidence for three groups: 1) Atlantic Ocean/West Africa, 2) Western Indian Ocean, and 3) Eastern Indian Ocean/Pacific Ocean. These would appear to correspond to the teuszii, plumbea and chinensis forms, respectively. However, no taxonomic revisions are recommended at this time, but the conservative view to two species (S. teuszii in W. Africa and S. chinensis in the Indo-Pacific) should be followed for the time being. The distinctness of S. teuszii is evident, but other taxonomic decisions should await further studies of genetics and morphometrics, currently underway.