A tiny, fossilized crustacean that lived 425 million years ago has been discovered, remarkably intact, in a rock formation in Herefordshire, England. Paleontologists say it represents a new genus and species, belonging to a class of shrimplike marine creatures called ostracods.

Despite their age, the two specimens were well preserved. They included the shell and the soft parts of the animal, including its body, limbs, eyes, gills and alimentary system.

“It gives us a really special insight into the biology of these animals,” said David Siveter of the University of Leicester in England. He and colleagues from the University of Oxford, Imperial College and Yale discuss the findings in the journal Proceedings of the Royal Society B.

The researchers determined that the animal had large eyes and seven pairs of limbs, with the front two pairs adapted for swimming.