Dino card No. 1316 of 2,027

Opisthocoelicaudia

Say it: oh-PISS-thoh-seh-lih-KAW-dee-uh

Name means: “posterior cavity tail”1

Ate: PlantsLong-necksLate Cretaceous

Opisthocoelicaudia was a big, long-necked plant eater that lived in the Late Cretaceous. It had a barrel-shaped body and four thick legs, like an elephant. Scientists found a nearly complete skeleton without the head and neck, so they know a lot about its body.1

Lived

72 to 66 million years ago4

Late Cretaceous

Fossils found in

Gobi Desert, Mongolia1 4

Food

Plants4 1

Length

11.4 to 13 m1

estimated from head to tail tip

Weight

8.4 tonnes to 25.4 tonnes1

Height

2.46 m1

hindlimb height, roughly hip height

Top speed

about 13 km/h (8 mph)

Running, estimate

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How tall was it?

hindlimb height, roughly hip height

How heavy was it?

as heavy as 4 elephants

as long as 3 cars parked in a rowas long as 72 bananas end to endas heavy as 17 carsas heavy as 5100 watermelonsabout as tall as a door

How big was Opisthocoelicaudia compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

How fast was it?

A person walking about 5 km/h (3 mph)

Opisthocoelicaudia about 13 km/h (8 mph)

A kid on a bike about 22 km/h (14 mph)

A galloping horse about 65 km/h (40 mph)

A cheetah about 100 km/h (62 mph)

cool stuff

Fun facts

Its tail vertebrae were shaped like ball-and-socket joints, which is unusual and gives it the name 'posterior cavity tail'.1

The skeleton had tooth marks from big meat-eating dinosaurs, which probably ate the carcass and carried away the head and neck.1

It could probably rear up on its hind legs to reach higher food, because its tail was strong and could act like a tripod.1 2

Its back vertebrae had split spines, creating a double row of bumps along its spine, a feature also seen in Diplodocus.1

It had six hip vertebrae, one more than most sauropods, which made its hips extra strong.1

The neck was about 5 meters (16 feet) long, which is medium for a sauropod.1

AI-made picture of Opisthocoelicaudia — An AI-made picture of how Opisthocoelicaudia might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.

you asked

Most asked questions about Opisthocoelicaudia

?How big was Opisthocoelicaudia?

It was a relatively small sauropod, measuring about 11.4 to 13 metres (37 to 43 feet) long. Its body mass has been estimated at between 8.4 and 25.4 tonnes in different studies.1

?What did Opisthocoelicaudia eat?

Like other sauropods, it was a herbivore that ate plants. It probably fed on a variety of vegetation in its floodplain and riverine environment.3

?When did Opisthocoelicaudia live?

It lived during the Late Cretaceous Period, specifically in the ?Upper Campanian or Lower Maastrichtian, about 72 to 66 million years ago.1 2

?Where was Opisthocoelicaudia found?

Its fossils were discovered in the Gobi Desert of Mongolia, in the Nemegt Formation. The type specimen was found at Altan Uul in Ömnögovi Province.1

?Could Opisthocoelicaudia rear up on its hind legs?

Yes, scientists think it could rear up on its hind legs to reach higher food. Its strong tail could act like a tripod to support its weight.1

?Is Opisthocoelicaudia a dinosaur?

Yes, it is a sauropod dinosaur. It belongs to the group Titanosauria and lived during the Late Cretaceous.1

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Myth buster

Myth: Some people think Opisthocoelicaudia was a kind of camarasaur, but scientists now know it was a titanosaur.

Truth: It was first classified as a camarasaurid, but later studies placed it in Titanosauria, a group of sauropods.1

For dino experts

Scientific name: Opisthocoelicaudia
Named by: Borsuk-Bialynicka 19774
Group: Long-necks
Family / clade: Saltasauridae4
Classification: Sauropodomorpha > Sauropoda > Titanosauria > Macronaria4
Age of the rocks: 72 to 66 million years (Maastrichtian)4
Rock formations: Nemegt4
Countries: Mongolia4
Fossil records: 1 in the Paleobiology Database4
Discovery: It was discovered in 1965 by a Polish-Mongolian expedition in the Gobi Desert. Polish paleontologist Maria Magdalena Borsuk-Białynicka named it in 1977.1 2
Still debated: Scientists debate whether Opisthocoelicaudia and Nemegtosaurus are actually the same species, because only the skull of Nemegtosaurus is known and Opisthocoelicaudia lacks a skull.1

Where the facts come from

Opisthocoelicaudia (en.wikipedia.org)
A NEW CAMARASAURID SAUROPOD OPISTHOCOELICAUDIA SKARZYNSKII GEN. N., SP. N. FROM THE UPPER CRETACEOUS OF MONGOLIA (palaeontologia.pan.pl)
Opisthocoelicaudia: a Late Cretaceous Mongolian titanosaur (en.alegsaonline.com)
Opisthocoelicaudia in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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