Apatosaurus ajax ah-PAT-oh-SOR-us
"Deceptive lizard"
You 1.8 m (5.9 ft) tall
Apatosaurus 22 m (72 ft) long
13 people holding hands
- Length
- 22 m (72 ft) — About 22 m long, ~25 tonnes — heavier and stockier than Diplodocus.
- Period
- Late Jurassic (155–150 Mya)
- Place
- North America · Western United States
- Food
- Herbivore — Low and mid-height plants — peg teeth for stripping leaves and ferns.
Apatosaurus was a thick-bodied cousin of Diplodocus, heavier and shorter overall but built on the same long-necked plan. For most of the 20th century it had the wrong head — early scientists mounted a Camarasaurus skull on Apatosaurus bones. The mistake wasn’t fully corrected in museums until the 1970s, after the right skull was identified.
What we know
- Same family as Diplodocus, but heavier and more thickly built.
- Famously had the wrong skull on display for almost 90 years.
- Massive vertebrae with deep hollows to save weight on the long neck.
- Found in the Morrison Formation across the American west.
What we guess
- Whether Apatosaurus and Brontosaurus are separate genera (the 2015 study says yes).
- Whether the thick neck was used in male-on-male combat, slamming necks together.
- Lifespan estimates range from 70 to 100 years based on bone histology.