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Apatosaurus is an interesting dinosaur, as here is one of the first big mistakes in dinosaur hunting. The name means ‘deceptive lizard’ and rightly so; it was also called ‘Brontosaurus’ (that name is no longer in use) in haste to name more dinosaurs. It later turned out that Brontosaurus was actually Apatosaurus. Now some scientists (notably Stephen J Gould in his book ‘Bully for Brontosaurus’) argue that they can be thought of as synonym for each other.

Apatosaurus is a rather large member of the sauropod group of dinosaurs. It is in the same family as diplodocus, Supersaurus, Suuwassea, and Barosaurus. They are all pretty big.

Dino Index

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Latin Name Apatosaurus
Everyday Name Apatosaurus
Length 23 meters
Height 9 meters
Weight 23 metric
Diet herbivore
Period Jurassic
Pronunciation Ah – pat – o – sor – us


What did they eat?

They ate plants, but scientists have some unclear ideas here. To begin with, these animals were so large they must have been eating continuously. Furthermore, the plants that they ate – conifers – were not highly nutritious. We know that they had help to digest these plants with gastroliths – fossilized stones that were in a gizzard (like birds) that help grind the plants into smaller pieces.

They also pose problems for breathing, since we if it had a reptilian system for air exchange it could not have given enough air to their blood to survive. Perhaps they had a system like birds… that would have worked, or they had another system that we are not familiar with.

Wrong Head

One of the early fossils found was found without a head nearby. The actual skull had been moved in the fossilization process and was not found near the body. This created a problem: what kind of head to mount in the museum? They actually decided to mount a Camarasaurus skull on the Apatosaurus,although it is not clear why, other than that scientists felt that a smaller skull could not ‘fit’ on this giant body. They reasoned that it would need a large mouth and strong teeth to eat enough to live, not realizing at the time that Apatosaurus had a gizzard like a bird that helped them digest food. Get the full story here.

Why Are They Called the ‘Deceptive Lizard’?

These dinosaurs have a chevron bone that is very similar to the mosasaur so it was considered ‘deceptive’. However, it seemed to live up to its name wonderfully; giving rise to the brontosaurus confusion, having the wrong head, posing questions about how it could possibly breath or eat enough to live.

On top of all this, scientists thought that they originally lived in the water so they could support their massive weight. This was strengthened by the discovery that their nostrils were on the top of their head (they could breathe underwater, it seemed…).

This was brought into question when someone noticed that all the fossils were found in dry places, and not near any large bodies of water.

Another misconception that occured was to think of them as dragging their tails. in fact, Apatosaurus tracks have been found and there were no tail tracks. This new model is portrayed in the popular dinosaur series ‘Walking with the Dinosaurs’.

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