Discovered four new species of sharks

Biologists found four new species of sharks capable of walking on the sea floor in shallow waters off Australia and New Guinea.

Sharks have roamed the world's oceans about 400 million years ago, much earlier than dinosaurs. While some species remain largely unchanged, others are evolving to adapt to changing habitat conditions.A walking shark is a prime example.

Epaulette leopard (Hemiscyllium michaeli) lives in the Milne Bay, eastern Papua New Guinea.(Photo: CNN).

In a new study published this week in the journal Marine and Freshwater Research , the scientists said they had stumbled across four new species of sharks while collecting DNA samples from another shark. All are thought to have developed the ability to walk on the seabed over the past 9 million years, of which the smallest species may have only begun to evolve two million years ago.

"This is very unusual because most sharks evolve slowly," said Gavin Naylor, director of the Shark Research Program at the University of Florida, USA. For example, the six gill sharks live in the deep sea, they seem to be stuck in time with the physical characteristics have not changed during the last 180 million years.

"This finding proves that modern sharks have extraordinary evolutionary power and high adaptability to changing environmental conditions , " adds Mark Erdmann, co-author of the study. Hemiscyllium michaeli , nearly a meter long, is one of four newly discovered walking sharks. They use the pectoral fins and pelvic fins to walk on the bottom of the sea, and can even crawl up coral reefs above water when the waters recede. This ability allows them to wriggle between tidal lakes to catch shrimp, crabs, small fish or whatever they find.

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