Deepest-dwelling land animal, “worm from hell,” is discovered in a gold mine

Scientists have found complex, multicellular creatures – worms – living a mile or more below the planet’s surface, deep in the Earth where it was thought previously that animals could not survive, BBC News reported.

The new species, nicknamed “worms from hell,” according to the Washington Post, is a nematode, or roundworm, that can tolerate temperatures higher than 100 degrees Fahrenheit and very low oxygen levels, and it feeds on subsurface bacteria, according to the New York Times. The worm is tiny, two hundredths of an inch at the longest.

The research could trigger scientific challenges and cause controversy because it places more complex life in conditions where scientists have generally thought that it couldn't exist, the Washington Post said.

Single-cell organisms have been known to live more than 9,000 feet below the surface of the Earth. But it was thought that the temperature, energy, oxygen and space constraints of that kind of environment were too extreme for multicellular organisms, according to the New York Times.

The discovery of Halicephalobus mephisto, named after Faust's Lord of the Underworld, in a shaft of the Beatrix gold mine in South Africa, is reported in the journal Nature.

The scientists had been searching for subsurface life for 15 years, focusing on the ultra-deep mines of South Africa, which penetrate more than 1.8 miles into the Earth. In the Beatrix gold mine, the two lead researchers, Gaetan Borgonie of the University of Ghent in Belgium and Tullis Onstott of Princeton University, found more than they were looking for: the tiny nematode, with nervous, digestive and reproductive systems. The researchers were able to get H. mephisto to reproduce, and the species is still "squirming around in the lab," Onstott said, according to msnbc.com.

The researchers say their findings should be taken into consideration in the search for life in other extreme conditions. Scientists seeking life beyond Earth are intrigued by the possibility that microbes could be living below the surface of Mars, in particular — a planet that is now cold, dry and bombarded by radiation but was once wetter, warmer and better-protected by an atmosphere, the Washington Post said. But with the new find, Borgonie said, “Life on Mars could be more complex than we imagined."

Michael Meyer, the lead scientist for Mars exploration at NASA, who was not involved in the study, said that researchers had assumed that any subsurface life on a planet like Mars would be unicellular, according to msnbc.com. But now, he said, "This kinds of opens it up to, well, even multicellular life could be possible."