Aetosaur

Part of speech: noun

Definitions

1. A type of prehistoric reptile from the Archosauria class that thrived in the Late Triassic and displayed adaptations for both land and water habitats
2. An ancient reptile distinguished by its flat body and armor, it existed during the Mesozoic era and is closely related to crocodilians
3. A prehistoric reptile known for its heavy body armor and existing during the Triassic era

Etymology: Aetosaurs were armoured, plant-eating archosaurs of the Late Triassic, and the name was coined in 1877 by the German palaeontologist Ferdinand von Huene, although the word itself is built from Greek. It combines "aetos", meaning "eagle", with "sauros", meaning "lizard". Modern dinosaurs and birds are archosaurs too, so the group sits in the same broad lineage that later produced the eagle, which is a neat irony given that the animals were ground-dwelling and heavily plated rather than aerial hunters. The "eagle" in the name appears to have been chosen for its sense of a sharp-beaked, hook-tipped creature, but the exact motivation is not something the records make clear, so the name is best read as a descriptive scientific coinage rather than a reference to any particular feature. The "-saur" ending follows the same pattern as "dinosaur" and other reptile names from the nineteenth century, which drew on Greek roots to label newly discovered fossils.