What does apatosaur mean?
An apatosaur is any member of Apatosaurus, a genus of enormous plant-eating sauropod dinosaurs that roamed western North America during the Late Jurassic period, roughly 150 million years ago. These animals were among the largest land creatures ever to exist, measuring up to about twenty-two or twenty-three metres long and weighing many tonnes, with small heads, peg-like teeth suited to stripping vegetation, long necks for browsing treetops, and whip-like tails. The common noun 'apatosaur' is used mainly in popular science books, museum exhibits, documentaries, and journalism; scientists writing formally refer instead to the genus name Apatosaurus. The word derives from the Greek roots 'apate', meaning deceit, and 'sauros', meaning lizard — a name given by Othniel Charles Marsh because one of its bones was initially mistaken for that of a different marine reptile. For general readers, 'apatosaur' serves as a convenient, evocative shorthand for one of the most iconic giants of the dinosaur age.
nounA very large herbivorous sauropod dinosaur of the genus Apatosaurus, of Late Jurassic North America, characterized by a massive body, a long neck and tail, and four columnar legs.
- Any large quadrupedal sauropod dinosaur of the genus Apatosaurus, native to Late Jurassic North America.
"The museum's reconstructed apatosaur skeleton towers over the entrance hall."
"An adult apatosaur could stretch more than twenty metres from nose to tail-tip."
"Footprints attributed to an apatosaur were preserved in the ancient lakebed mudstone."
Standard regular plural, formed by adding -s; used when referring to multiple individuals of the genus.
"Fossil evidence suggests apatosaurs may have traveled in herds."
The name literally means 'deceptive lizard' — because its tail bones were so easily confused with those of another prehistoric reptile that paleontologists doubted their own discovery.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of apatosaur
The word 'apatosaur' comes from the genus name Apatosaurus, coined by American paleontologist Othniel Charles Marsh in 1877 from the Greek elements 'apate' (deceit or fraud) and 'sauros' (lizard). Marsh chose 'deceptive lizard' because the chevron bones of the tail resembled those of mosasaurs, leading him initially to suspect the remains belonged to an aquatic reptile rather than a land-dwelling dinosaur. The English form 'apatosaur' simply drops the '-us' ending of the genus name to create a usable common noun, following the same convention that produced 'dinosaur' and other familiar terms.
Related word forms
How apatosaur is actually used
'Apatosaur' is the informal common-noun form of the genus name Apatosaurus and appears chiefly in popular science writing, museums, and journalism; formal taxonomic literature uses 'Apatosaurus'. The word is countable and typically used with articles or plurals.
Easily confused with apatosaur
Brontosaurus was long considered a junior synonym of Apatosaurus; after a 2015 study it was re-erected as a separate genus, so 'apatosaur' refers to Apatosaurus proper rather than to every long-necked giant once labeled Brontosaurus.