This video from the USA is called Clymene Dolphins off Cape Hatteras, NC in May 2008, filmed by G. Armistead.
This video is called Untamed Americas: Spinner Dolphins.
From Wildlife Extra:
Rare natural hybridisation results in a dolphin with genetic similarities to both the spinner and striped
January 2014: A newly published study on the clymene dolphin, a small, sleek marine mammal living in the Atlantic Ocean, shows that this species arose through natural hybridisation between two dolphins species. In a molecular analysis including the closely related spinner and striped dolphins, scientists concluded that the clymene dolphin is the product a process that is common for plants, fishes and birds, but quite rare in mammals.
“Our study represents the first such documented instance of a marine mammal species originating through the hybridisation of two other species,” said Ana R. Amaral, lead author of the study and research associate at the American Museum of Natural History. “This also provides us with an excellent opportunity to better understand the mechanisms of evolution.”
The classification of the clymene dolphin has been a longstanding challenge to taxonomists, who initially considered it to be a subspecies of the spinner dolphin. Then in 1981, thorough morphological analyses established it as a recognised distinct species. In the current study, researchers sought to clarify outstanding questions about the dolphin’s origin and relationships with rigorous genetic analyses.
Based on research conducted at the American Museum of Natural History’s Sackler Institute for Comparative Genomics, the authors examined the nuclear and mitochondrial DNA from skin samples obtained from both free-ranging dolphins by means of biopsy darts and deceased dolphins obtained through stranding events. Specifically, the team discovered that while the mitochondrial genome of the clymene dolphin most resembled the striped dolphin, the nuclear genome revealed a closer relation to the spinner dolphin. The findings reveal not only more about the species, but how natural hybridisation can create an entirely new species of mammal over time.
The clymene dolphin grows up to nearly 7ft in length and inhabits the tropical and temperate waters of the Atlantic Ocean. Threats to the species include incidental capture as by catch in fishing nets, which in some parts of the range has turned into direct hunts for either human consumption or shark bait.
This video is called Striped Dolphin Species Identification.