Comments: Mead and Brownell (in Wilson and Reeder 1993) included D. bairdii, D. capensis, and D. tropicalis in D. delphis. Heyning and Perrin (1994) examined variation in Delphinus in the eastern North Pacific and found two distinct forms, a short-beaked form that they recognized as D. capensis (D. bairdii is a junior synonym), and a long-beaked form regarded as D. delphis. They noted that the status of D. tropicalis needs to be examined to determine if it is an extremely long-beaked form along a cline of D. capensis or a third species of Delphinus. Mead and Brownell (in Wilson and Reeder 2005) recognized D. capensis and D. delphis (but not D. tropicalis) as distinct species.