A team of Virginia Tech researchers have discovered fossils of kinorhynch worms - commonly known as mud dragons - dating back more than 530 million years.
The historic find - made in South China - fills a huge gap in the known fossil record of kinorhynchs, small invertebrate animals that are related to arthropods, featuring exoskeletons and segmented bodies, but not jointed legs.
The first specimen was unearthed in rocks in Nanjiang, China, in 2013 and more fossils were found later that year and in 2014.