Dino card No. 0295 of 2,027

Brachauchenius

Say it: BRAK-oh-KEE-nee-us

Name means: “short neck”1

Ate: MeatPlesiosaursEarly Cretaceous to Late CretaceousNot technically a dinosaur

Brachauchenius was a huge marine reptile with a big head and a short neck, unlike many other plesiosaurs. It swam in the warm seas of the Late Cretaceous, using its flippers to chase fish and other prey. Even though it looked like a dinosaur, it was actually a plesiosaur, a swimming reptile.1

Fun fact: this sea reptile swam while dinosaurs walked on land. Everyone calls them dinos, but they were a different branch of reptiles.

Lived

126 to 90 million years ago3

Early Cretaceous to Late Cretaceous

Fossils found in

Fossils have been found in the United States (Kansas, Colorado, South Dakota, Texas, Utah, Alabama), Colombia, Morocco, and the United Kingdom.3 1

Food

Meat3

Length

5.3 to 11 m1 3

holotype estimated at 5.3 m; Carpenter 1996 gives ~11 m for a very large specimen

Weight

2.2 tonnes1

holotype estimate

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How heavy was it?

as heavy as 1.5 cars

as long as 2.5 cars parked in a rowas long as 61 bananas end to endas heavy as 73 big dogsas heavy as 440 watermelons

How big was Brachauchenius compared to YOU?

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cool stuff

Fun facts

Brachauchenius had a skull that was about 90 centimeters (35 inches) long, which is almost as long as a grown-up person's arm.1

Its name means 'short neck' because it had a much shorter neck than most other plesiosaurs, which usually had long, swan-like necks.1

The first fossil was found in 1884 in a quarry in Kansas, USA, and it was later named Brachauchenius lucasi in 1903.1

Brachauchenius lived during the Late Cretaceous, about 100 to 90 million years ago, when the middle of North America was covered by a shallow sea.1 3

Some fossils that were once thought to be Brachauchenius turned out to belong to other animals, like Megacephalosaurus, which had a similar skull.1

Brachauchenius had two pairs of large flippers and a short tail, which helped it swim through the water like a sea lion.1

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

?How big was Brachauchenius?

About 5.3 metres (17 feet) long and weighed around 2.2 tonnes (2.4 short tons). One large specimen may have been at least 7 metres (23 feet) long.1 2

?What did Brachauchenius eat?

It ate fish and other prey that it chased in the warm Cretaceous seas. Its large skull and strong jaws helped it catch food.1

?When did Brachauchenius live?

It lived during the Late Cretaceous, about 100 to 90 million years ago.1

?Where was Brachauchenius found?

Fossils have been found in Kansas, USA, and also in Morocco, North Africa. The first fossil was discovered in a quarry near Delphos, Kansas in 1884.1

?Is Brachauchenius a dinosaur?

No, it is not a dinosaur. It is a plesiosaur, a type of marine reptile that swam in the ocean.1

?Why did Brachauchenius have a short neck?

Its name means 'short neck' because it had a much shorter neck than most other plesiosaurs, which usually had long, swan-like necks. This helped it be a powerful swimmer.1

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Myth buster

Myth: Some people think Brachauchenius was a dinosaur because it lived in the sea and looked scary.

Truth: Brachauchenius was not a dinosaur. It was a plesiosaur, a type of marine reptile that lived at the same time as dinosaurs but was not closely related to them.1

For dino experts

Scientific name: Brachauchenius
Named by: Williston 19033
Group: Plesiosaurs
Family / clade: Pliosauridae3
Classification: Plesiosauria > Pliosauridae > Sauropterygia3
Age of the rocks: 126 to 90 million years (Barremian / Turonian)3
Rock formations: Greenhorn Limestone, Tropic Shale, Paja3
Countries: USA, Colombia, United Kingdom, Morocco3
Fossil records: 11 in the Paleobiology Database3
Discovery: The first Brachauchenius fossil was found in 1884 by a quarry owner in Kansas, USA. It was later named by Samuel Wendell Williston in 1903, who called it Brachauchenius lucasi after Frederic Lucas.1
Still debated: Scientists are still not sure exactly which rock layer the first Brachauchenius fossil came from, because the original notes were not clear.1

Where the facts come from

Brachauchenius (en.wikipedia.org)
Brachauchenius (oceansofkansas.com)
Brachauchenius 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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