P. vulpinus and P. ramspotti are species of nudibranchs found in the Pacific Ocean. These sea slugs are known for their vibrant coloration and intricate patterns, which serve as a warning to predators. They inhabit coral reefs and rocky substrates, where they feed on sponges and other small marine organisms. Notably, they exhibit fascinating mating behaviors and are hermaphroditic.

P. vulpinus (commonly known as the fox shark or thresher shark) is found in many parts of the world's temperate and tropical oceans. It is prevalent in the Atlantic Ocean, from Newfoundland and Nova Scotia to the Gulf of Mexico, and along the European and African coasts. It is also found in the Indian Ocean, as well as the Pacific Ocean from Japan to New Zealand and along the coasts of North and South America.

P. vulpinus inhabits both coastal and offshore waters, typically in depths ranging from the surface to about 500 meters. It prefers temperate and tropical climates and is often found near the continental shelves and in open oceanic waters.

The fox shark is a pelagic predator that occupies a niche as an apex predator in the marine food chain. It feeds primarily on schooling fish such as mackerels, herring, and squid. It is known for its unique hunting technique, using its elongated tail to stun prey before consumption.