Ornithosaur

Part of speech: noun

Definitions

1. Any of the extinct flying reptiles that lived during the Mesozoic era, with wings formed from a membrane stretched along a very long fourth finger
2. An ancient winged reptile belonging to the pterosaur group, which ruled the skies alongside the dinosaurs before dying out
3. A prehistoric flying reptile of the Mesozoic period, distinguished by its membranous wings supported by an elongated finger

Etymology: Ornithosaur is a term for the flying reptiles now usually called pterosaurs, and it was coined in 1870 by the English palaeontologist Harry Govier Seeley. Seeley was studying a specimen that showed a bird-like arrangement of bones, and he argued that the animal was closer to birds than to other reptiles, so he gave it a name built from the Greek "ornis", meaning bird, and "sauros", meaning lizard. The new label carried a claim: that these creatures were bird-lizards rather than simply flying reptiles. The claim did not survive. Later work showed that pterosaurs were not closely related to birds, and the name "pterosaur", from Greek "pteron" meaning wing, was already in use by then and became the standard term. Ornithosaur is now largely confined to older books and to the history of palaeontology, where it records an early theory about how these animals were related to living creatures.

Synonyms: pterosaur, pterodactyl