A new study has unexpectedly discovered that a common parasite of modern oysters actually started infecting bivalves hundreds of millions of years before the dinosaurs went extinct. The research, published in iScience, used high-resolution 3D scans to look inside 480-million-year-old shells from a Moroccan site known for its exceptionally well-preserved sea life. The scans revealed...

A newly described fossil reveals that leeches are at least 200 million years older than scientists previously thought, and that their earliest ancestors may have feasted not on blood, but on smaller marine creatures. “This is the only body fossil we’ve ever found of this entire group,” said Karma Nanglu, a paleontologist with the University...