An ancient, insect-like sea creature with a fan-shaped tail and a shell wrapped around its body, it swam upside down and looked like a taco. But this taco could bite back.
Newly discovered fossils of the extinct arthropod Odaraia alata recently gave scientists their first glimpse of Odaraia's jaw-like structures, called mandibles. These small, paired appendages near the mouth bite, hold and tear food, and arthropods with these mouthparts are called mandibulates.
The first mandibulates evolved in oceans during the ...