👉 Eusuchian is a term used in geology that refers to the oldest known organism on Earth, which lived around 500 million years ago. The term "eusuchian" comes from the Greek word for "ear," as it was thought that these organisms had ears, but this has not been confirmed by modern science. They are also called "ear-like creatures" because they have a similar appearance to other echinoderms (animals with hard shells) and their unique