The mammals of the open tropical oceans of the world...
Stenella longirostris, 'Spinner Dolphin' (Papua New Guinea). This species probably includes many species; as the very least there are many distinct forms around the world. In the middle of the Pacific Ocean, far away from land, I have seen very tiny forms of Spinner Dolphins.
The 'Bottlenose Dophin' is now usually considered to be three or even four different species. Two occur across larger areas of the tropics, with the larger 'Common Bottlenose' Tursiops truncatus, being more widespread and also found in deeper more open water. The closer they examine these two species, the less closely related they seem to be.
Tursiops aduncus, 'Inshore (Indo-Pacific) Bottlenose Dolphin'. Usually found in coastal waters, around the Indo-Pacific oceans.
Megaptera novaeangliae, 'Humpback Whale' (Kimberley coast, Australia).