“We’ve only named about a million species of insects and there are almost certainly five to eight million undescribed,” said Dr George McGavin.
The filming was part of a new BBC/Discovery Channel/Terra Mater TV co-production called The Dark: Nature’s Nighttime World.
“[It’s] the most unbelievable thing I’ve ever seen,” biologist and presenter, Dr McGavin, told BBC Nature.
“It swims underwater and uses its front legs as a proper breaststroke and its hind legs kicking out. It was just amazing,” he said.
The team were alerted to the cave by Italian researchers from the association La Venta, who had noted the presence of an unusual looking catfish when they recently explored the caves for the first time.
Dr McGavin and the film crew went with them during their return trip to the cave and found a specimen with the hallmarks of an underground evolutionary history.
source : http://www.bbc.co.uk/nature/19102700