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The Manta genus is what is commonly thought of as manta rays. There is also a Mobula genus that are smaller bottom-dwelling rays. To confuse things even further, two of the Mobula species, Mobula mobular and Mobula hypostoma, are also commonly referred to as the devil fish and lesser devil ray, respectively.
It was previously thought that three species of giant manta existed:
1) Manta birostris - Atlantic manta ray
2) Manta hamiltoni - Pacific manta ray
3) Manta alfredi - Prince Alfred's manta ray
Recent studies of genetic samples, however, show that they are all the same species - Manta birostris.
These graceful swimmers swim by moving their wing-like pectoral fins, which can grow up to 9 external link m wide, but average about 6.7 external link m. The largest weigh about 1,350 external link kg. Mantas are dark brown to black on the dorsal side with pale margins; they are mostly white on the ventral side.