Researchers have discovered two previously unknown species of bottom-dwelling fish in the Gulf of Mexico, living right in the area affected by the BP oil spill.

Researchers identified new species of pancake batfishes, a flat fish rarely seen because of the dark depths they favor. They are named for the clumsy way they walk along the sea bottom, like a bat crawling.

One of the fishes that we describe is completely restricted to the oil spill area, John Sparks of the American Museum of Natural History in New York, said in a statement released on Thursday.

If we are still finding new species of fishes in the Gulf, imagine how much diversity, especially microdiversity, is out there that we do not know about.

Writing in the Journal of Fish Biology, Sparks and his colleagues named the species as Halieutichthys intermedius and H. bispinosus. A third already known species called H. aculeatus also only lives in waters affected by the spill, they said.

Pancake batfishes have round, flat bodies with giant heads and mouths they can thrust forward. They use arm-like fins to drag themselves along the bottom and a modified dorsal fin excretes fluid to lure prey.

Sparks said the three species had been considered just one species, but his team found distinct differences.

These discoveries underscore the potential loss of undocumented biodiversity that a disaster of this scale may portend, he said.

BP aims to plug the well late this month or in August.

The well has pumped millions of gallons (liters) of oil into the Gulf, coating shorelines and animals and having as yet unknown effects on creatures living in deep waters.

It threatens to devastate the Gulf region's multibillion-dollar fishing and tourist industries.

(Reporting by Maggie Fox, editing by Vicki Allen)

Oil Spill