Dino card No. 0054 of 2,027

Alamosaurus

Say it: AL-ah-mo-SORE-us

Name means: “Alamo lizard”1

Ate: PlantsLong-necksLate Cretaceous

Alamosaurus was a giant, long-necked plant-eater that stomped through what is now North America near the very end of the Age of Dinosaurs. It was one of the last big sauropods to ever live, and it may have traveled in herds.5 1

Lived

84 to 66 million years ago5

Late Cretaceous

Fossils found in

New Mexico, Texas, and Utah in the USA, and Chihuahua in Mexico5 2

Food

Plants5 1

Length

21 m1

Weight

30 tonnes to 35 tonnes3

based on known adult specimens including TMM 41541-1

Height

5 m3

at the shoulder

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?

at the shoulder

How heavy was it?

as heavy as 6 elephants

as long as 5 cars parked in a rowas long as 120 bananas end to endas heavy as 7000 watermelonsas tall as 2.5 doors stacked up

How big was Alamosaurus compared to YOU?

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cool stuff

Fun facts

Alamosaurus is the only sauropod from the Late Cretaceous that has been found in North America, making it a very special dinosaur.1

Its fossils come from rocks that are between about 83.6 and 66 million years old, so it lived right up to the end of the dinosaur era.2

Scientists think Alamosaurus lived in groups, because its bones are sometimes found together in large numbers.2

It was a ground-dwelling herbivore, meaning it walked on land and ate plants, not like some other long-necks that might have lived in water.5

Alamosaurus laid eggs, just like other dinosaurs, even though it was huge.2

The name 'Alamosaurus' comes from the Ojo Alamo Formation in New Mexico, where the first fossils were found, not from the Alamo mission in Texas.5

AI-made picture of Alamosaurus — An AI-made picture of how Alamosaurus 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 Alamosaurus

?How big was Alamosaurus?

About 26 metres (85 ft) long, 5 metres (16 ft) tall at the shoulder, and weighed up to 30 to 35 tonnes (33 to 39 short tons). Some specimens suggest it could have been even larger, possibly the largest dinosaur found in North America.3 1

?What did Alamosaurus eat?

It was an herbivore, meaning it ate plants. It had a long neck to reach high or low vegetation.1 3

?When did Alamosaurus live?

It lived during the Late Cretaceous period, about 70 to 66 million years ago, right up to the end of the Age of Dinosaurs.1 3

?Where was Alamosaurus found?

Fossils have been found in the southwestern United States, including New Mexico, Texas, Utah, and Wyoming. The first fossils came from the Ojo Alamo Formation in New Mexico.3 4

?Is Alamosaurus a dinosaur?

Yes, it is a dinosaur. It belongs to the group called sauropods, which were large, long-necked, plant-eating dinosaurs.1 3

?Was Alamosaurus bigger than T. rex?

Yes, much bigger. Alamosaurus was about 26 metres (85 ft) long and weighed up to 35 tonnes, while T. rex was about 12 metres (40 ft) long and weighed around 8 tonnes.3

?Did Alamosaurus have any armor?

Yes, its body was partly covered with bony armor called osteoderms, which acted like a protective shield.3

?How did Alamosaurus get to North America?

Scientists think it may have migrated from South America or Asia, because no other sauropods lived in North America for about 30 million years before Alamosaurus appeared.3 4

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Myth buster

Myth: Some people think Alamosaurus lived in water because it was a sauropod, but that's not true.

Truth: Alamosaurus was a ground-dwelling dinosaur, and its bones show it was adapted for life on land.2

For dino experts

Scientific name: Alamosaurus
Named by: Gilmore 19225
Group: Long-necks
Family / clade: Saltasauridae5
Classification: Sauropodomorpha > Sauropoda > Titanosauria > Macronaria5
Age of the rocks: 84 to 66 million years (Campanian / Maastrichtian)5
Rock formations: Ojo Alamo, Javelina, North Horn5
Countries: USA, Mexico5
Fossil records: 38 in the Paleobiology Database5
Discovery: Alamosaurus was named by Charles W. Gilmore in 1922, based on fossils found in the Ojo Alamo Formation of New Mexico, USA.5 1
Still debated: Scientists still debate exactly how Alamosaurus is related to other titanosaurs, and whether some fossils from Mexico really belong to this genus.5

Where the facts come from

Alamosaurus | Natural History Museum (nhm.ac.uk)
PBDB Taxon (paleobiodb.org)
Alamosaurus - Wikipedia (en.wikipedia.org)
Alamosaurus - Big Bend National Park (U.S. National Park Service) (nps.gov)
Alamosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at [email protected] and we will fix it.

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