Dino card No. 0772 of 2,015

Halisaurus

Say it: HAL-ih-SORE-us

Name means: “sea lizard”1

Ate: MeatMosasaursLate CretaceousNot technically a dinosaur

Halisaurus was a small, sleek marine lizard that swam in the warm seas of the Late Cretaceous. It was not a dinosaur, but a mosasaur, a relative of today's monitor lizards. It used its long tail and flippers to chase fish and other prey.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

86 to 62 million years ago2

Late Cretaceous

Fossils found in

North America (USA: New Jersey, Maryland, Delaware, California, North Carolina, Georgia), Africa (Morocco, Angola, Egypt, Niger, Congo-Kinshasa), South America (Peru, Chile, Argentina), Middle East (Jordan)2 1

Food

Meat2

Length

3 to 4 m1

Artist's life restoration of Halisaurus — How Halisaurus may have looked, by DiBgd. CC BY-SA 4.0, via Wikimedia Commons. Scientists still argue about colours and details.

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

cool stuff

Fun facts

Halisaurus was named by famous fossil hunter Othniel Charles Marsh in 1869.1

It was a small mosasaur, only about 3 to 4 metres long, much smaller than giants like Tylosaurus.1

Its flippers were not as specialized as those of later mosasaurs, so it was probably a slower swimmer.1

Fossils of Halisaurus have been found on every continent except Australia and Antarctica.2

The species Halisaurus onchognathus is known only from remains that were destroyed during World War II, so scientists are not sure if it was a real species.1

Halisaurus lived from about 85 to 66 million years ago, during the Late Cretaceous.2

Myth buster

Myth: Halisaurus was a dinosaur.

Truth: Halisaurus was a mosasaur, a marine reptile closely related to modern monitor lizards, not a dinosaur.1

For dino experts

Scientific name: Halisaurus
Named by: Marsh 18692
Group: Mosasaurs
Family / clade: Mosasauridae2
Classification: Mosasauroidea2
Age of the rocks: 86 to 62 million years (Santonian to Danian)2
Rock formations: Navesink, Severn, Marshalltown2
Countries: USA, Morocco, Chile, Peru, Jordan, Angola2
Fossil records: 30 in the Paleobiology Database2
Discovery: Halisaurus was named by Othniel Charles Marsh in 1869 based on a partial skull and vertebrae found near Hornerstown, New Jersey.1
Still debated: Scientists are not sure how many species of Halisaurus really existed, because some fossils are very fragmentary.1

Where the facts come from

Halisaurus (en.wikipedia.org)
Halisaurus 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 hello@dinowiki.app and we will fix it.