Even when they're not in tornado form, many sharks are efficient, speedy predators. But not all. As a species recently discovered in Indonesia shows, some sharks prefer to avoid that whole torpedo-with-teeth thing and just amble along.The shark, dubbed Hemiscyllium halmahera in the Aqua paper describing it, is a member of the longtail carpet shark family. Also known as bamboo sharks, the members of Hemiscyllidae are small, bottom-dwelling sharks that have notably long tails. Found in shallow waters in Asia and Australia, some bamboo sharks have developed a unique strategy for patrolling their reef habitats: They walk.The new shark is closely related to the epaulette shark, a species well known for its walking gait. The sharks feed on crustaceans and other small reef and bottom creatures, and it would appear walking along rocky ocean bottoms makes more sense than trying to swim. As you can see in the above video, H. halmahera's fin-tip gait is surprisingly agile, and epaulette sharks have actually been studied to try to sort out the root development of four-legged locomotion.Epaulette sharks are fascinating examples of evolution. Aside from the walking, they've evolved to deal with their shallow reef environments in another fashion: They are extremely tolerant of low-oxygen situations, like when they're trapped in a small pool by receding tides, thanks to physiological changes that allow them to cut back on their oxygen needs while protecting blood flow to their brains.Found off the coast of the island of Halmahera in New Guinea, H. halmahera was described based on a pair of specimens averaging about 30 inches. According to the research team of Gerald Allen, Mark Erdmann, and Christine Dudgeon, the new shark is similar to H. galei (which Allen and Erdmann described in 2008), but differs based on its coloring.Finding individuals that don't look alike doesn't necessarily mean they're different species, but in this case the researchers argue that they are "clearly differentiated." Regardless, the find is a fascinating one, as it highlights how something like walking—which we take for granted all the time—can evolve anywhere it provides an advantage, including for a species of slow-moving sharks.@derektmead
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