Scientists discover fossils of ancient microscopic worms

Scientists have discovered fossils of 530 million-year-old microscopic worms, filling a huge gap in the known fossil record of kinorhynchs -- small invertebrate animals that are related to arthropods.

A team of researchers discovered fossils of kinorhynch worms -- commonly known as mud dragons -- in China's Nanjiang province, a Virginia Tech statement said.

"Kinos represent an animal group that is related to arthropods -- insects, shrimps, spiders, etc. -- which are the most diverse group of animals on the planet," said Shuhai Xiao, a professor of geobiology in the department of geosciences, part of the College of Science at Virginia Tech.

Shuhai referred to kinorhynchs as "kinos" for short.

"Although arthropod fossils date back to more than 530 million years ago, no kino fossils have ever been reported. This is a huge gap in the fossil record, with more than 540 million years of evolutionary history undocumented. Our discovery is the first report of kino fossils," he added.

Shuhai said the new fossil can tell more about how and why body segmentation evolved many times among not only arthropods, but several other groups of animals.

Scientists believe kinos and arthropods should have evolved more than 540 million years ago.

More so, the authors found that E. rarus has a number of similarities with living kinorhynchs, suggesting a close evolutionary relationship.

The discovery and resulting research is a collaborative effort with Xiao's geosciences department, the Virginia Tech College of Engineering, the Chinese Academy of Sciences and Chang'an University in China's Xi'an city.