Dino card No. 1601 of 2,027

Scalamagnus

Say it: skah-lah-MAG-nus

Name means: “large staircase, referring to the Grand Staircase-Escalante National Monument where it was found”1

Ate: MeatPlesiosaursLate CretaceousNot technically a dinosaur

Scalamagnus was a small, fast-swimming marine reptile that lived in the warm, shallow sea that once covered North America. It had a long snout full of sharp teeth and used its four flippers to zoom through the water after fish and squid.1 2

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

Lived

94 to 90 million years ago2

Late Cretaceous

Fossils found in

Utah, USA, in the Tropic Shale formation1 2

Food

Meat2 1

Length

3.2 m1

estimated from the holotype skeleton

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 3 dogs nose to tailas long as 18 bananas end to end

How big was Scalamagnus compared to YOU?

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

cool stuff

Fun facts

Scalamagnus was originally thought to be a species of Dolichorhynchops, but scientists later gave it its own name in 2023.1

One Scalamagnus skeleton was found with 289 stomach stones (gastroliths), which is very unusual for this group of plesiosaurs.1

The stomach stones weighed about 518 grams in total, and most were smaller than 2 grams.1

It lived about 93 to 91 million years ago, during the early Turonian stage of the Late Cretaceous.1

Scalamagnus was a polycotylid plesiosaur, a group known for having short necks and large heads, unlike the long-necked plesiosaurs.1

The name Scalamagnus honors the Grand Staircase-Escalante National Monument in Utah, where its fossils were dug up.1

AI-made picture of Scalamagnus — An AI-made picture of how Scalamagnus 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.

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For dino experts

Scientific name: Scalamagnus
Named by: Clark et al. 20242
Group: Plesiosaurs
Family / clade: Polycotylidae2
Classification: Plesiosauria > Sauropterygia2
Age of the rocks: 94 to 90 million years (Turonian)2
Rock formations: Tropic Shale2
Countries: USA2
Fossil records: 2 in the Paleobiology Database2
Discovery: The first fossils were found between 2003 and 2005 by the Museum of Northern Arizona in the Tropic Shale of Utah. It was named Scalamagnus tropicensis in 2023 by Robert Clark, Robin O'Keefe, and Sara Slack.1 2
Still debated: Scientists are not sure why Scalamagnus had so many stomach stones, since most other polycotylids did not have them.1

Where the facts come from

Scalamagnus (en.wikipedia.org)
Scalamagnus 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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