Dino card No. 1172 of 2,027

Mesoleptos

Say it: mez-oh-LEP-tos

Name means: “middle scale”1

Ate: MeatMosasaursLate CretaceousNot technically a dinosaur

Mesoleptos was a marine lizard that swam in warm seas during the time of the dinosaurs. It was a mosasaur, a relative of the giant sea monsters like Mosasaurus, but much smaller. Its fossils have been found in Europe and the Middle East.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

100 to 90 million years ago4

Late Cretaceous

Fossils found in

Croatia, Slovenia, and Palestine2

Food

Meat2

Length

1 m3

rough estimate

Top speed

about 12 km/h (7 mph)

Swimming, estimate

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 2 house cats nose to tailas long as 6 bananas end to end

How big was Mesoleptos 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)

Mesoleptos about 12 km/h (7 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

Mesoleptos lived during the Late Cretaceous period, about 100 to 90 million years ago.2

It was a type of mosasaur, which are marine reptiles that are not dinosaurs but are related to modern lizards and snakes.1

The first fossils of Mesoleptos were found in Slovenia, in rocks that were once a shallow sea.2

Mesoleptos had a long, slender body and probably swam like an eel, wiggling through the water.1

Scientists are not sure exactly what Mesoleptos ate, but they think it was a predator of small sea animals.2

AI-made picture of Mesoleptos — An AI-made picture of how Mesoleptos 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: Mesoleptos
Named by: Cornalia and Chiozza 18524
Group: Mosasaurs
Family / clade: Aigialosauridae4
Classification: Mosasauroidea4
Age of the rocks: 100 to 90 million years (Cenomanian / Turonian)4
Rock formations: Bet Meir or Amminadav, Starigrad Limestone4
Countries: Palestine, Slovenia, Croatia4
Fossil records: 3 in the Paleobiology Database4
Also known as: Mesoleptos (older names now counted as the same animal)4
Discovery: Mesoleptos was named by Italian scientists Cornalia and Chiozza in 1852, based on fossils from Slovenia.2 1
Still debated: Scientists are still debating whether Mesoleptos belongs to the family Aigialosauridae or is a more primitive mosasaur.2

Where the facts come from

Mesoleptos (en.wikipedia.org)
PBDB Taxon (paleobiodb.org)
PaleoCodex :: Mesoleptos (paleocodex.com)
Mesoleptos 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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