
thumb|Rudist bivalve, Maurens Formation, Upper Cretaceous, southwestern France
thumb|Rudist bivalve, Maurens Formation, Upper Cretaceous, southwestern France
Rudists are a group of extinct box-, tube- or ring-shaped marine heterodont bivalves belonging to the order Hippuritida that arose during the Late Jurassic and became so diverse during the Cretaceous that they were major reef-building organisms in the Tethys Ocean, until their complete extinction at the close of the Cretaceous.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).