Astronauts have identified a new species of crustaceans during the European Space Agency's (ESA) CAVES training program.

Astronauts from International Space Station partner nations are given training for a week underground to learn to work in multi-cultural teams in harsh conditions. During their week-long stay in caves in Sardinia, Italy, astronauts carried out scientific research work including geology, meteorology, surveying and sorting organisms living underground. 

They set baits to attract the organisms living in a nearby pond and in other places. Biological sampling program developer, Paolo Marcia, cooked up a special menu to tempt the underground life. "I created really stinky bait made of liver and rotten cheese," said Marcia.

Astronauts collected few samples of less commonly known species. On the last day of the training session, they captured a new species of crustaceans. Based on molecular analysis, researchers confirmed that the samples belonged to the suborder of terrestrial isopods that are commonly known as woodlice.

Experts were surprised to find woodlice living in water, as they are known to have evolved from aquatic life and adapted to live on land.

"This find is important because the few aquatic woodlice we know of were thought to be primitive forms from which terrestrial woodlice had evolved. Now it is clear that these animals have evolved to live in water again," isopod specialist Stefano Taiti said in a release from ESA.

"It is changing our point of view on evolutionary processes in regards to terrestrial isopods living in an aquatic environment," he said.

The findings show evidence that evolution is not a one-way process and species can evolve to live in previously known habitats, Taiti concluded.