Providing potentially priceless information on the evolution of life, an unexpected treasure trove of tiny marine organisms from the mysterious mid-Ordovician period (some 462 million years ago) has been unveiled at Castle Bank, in Powys, Wales. Discovered by a team led by the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), the site comprises over 150 species, with many of miniaturised body size.
Originally discovered in 2020 and now described in detail in a study published in Nature Ecology & Evolution, the site contained over 150 species, almost all of them new. Many of the animals are very small, at only 1–3 mm long, but they preserve minute details. They range from arthropods like crustaceans and horseshoe crabs to various types of worms, sponges, starfish, and many, many more. In some animals, internal organs such as digestive systems and even nerves are preserved, together with the limbs of tiny arthropods and delicate filter-feeding tentacles. Such exquisite detail is known from the best Cambrian faunas, but not previously from the Ordovician.The range of fossils also includes several unusual discoveries, from unexpectedly late examples of Cambrian animals looking like opabiniids (weird proto-arthropods with a long proboscis) and wiwaxiids (slug-like mollusks armored with scales), to tantalising, unexpectedly early fossils that resemble modern goose barnacles, cephalocarid shrimps (which have no fossil record at all) and possibly even a marine relative of insects.
The Ordovician was a critical time in the history of life with an extraordinary diversification of animals that produced hard skeletons and abundant fossils. More familiar ecosystems like today’s coral reefs appeared by the end of the Ordovician.
Image: Reconstruction of the Castle Bank community. Credit: YANG Dinghua
More information: A Middle Ordovician Burgess Shale-type fauna from Castle Bank, Wales (UK), Nature Ecology & Evolution (2023). DOI: 10.1038/s41559-023-02038-4
Journal information: Nature Ecology & Evolution
