Dino card No. 0012 of 2,027

Acamptonectes

Say it: ak-amp-ton-EK-teez

Name means: “stiff swimmer”1

Ate: MeatIchthyosaursEarly CretaceousNot technically a dinosaur

Acamptonectes was a fast-swimming marine reptile that lived in the Early Cretaceous seas. It had a stiff body and large eyes, perfect for hunting fish and squid in the deep ocean.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

133 to 126 million years ago3

Early Cretaceous

Fossils found in

England (Speeton Clay Formation) and Germany1 3

Food

Meat1 3

Length

3 m1

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 3 dogs nose to tailas long as 17 bananas end to end

How big was Acamptonectes compared to YOU?

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

cool stuff

Fun facts

Acamptonectes belongs to a group called ophthalmosaurids, which had very large eyes for seeing in dark, deep water.1 2

Its name means 'stiff swimmer' because its body was unusually rigid, helping it move fast through the water.1

Acamptonectes lived about 133 to 129 million years ago, during the Hauterivian stage of the Early Cretaceous.1

Scientists once thought most ichthyosaurs died out at the end of the Jurassic, but Acamptonectes shows they survived and thrived into the Cretaceous.2 1

The first Acamptonectes fossil was found in 1958 by geology students near Speeton, England, but it was not named until 2012.2 1

Its teeth had tiny ridges along the length, which helped it grip slippery prey like fish and squid.1

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

?Was Acamptonectes a dinosaur?

No, it was a marine reptile called an ichthyosaur, not a dinosaur.1

?How big was Acamptonectes?

It was about 3 metres (9.8 feet) long.1

?What did Acamptonectes eat?

It likely ate soft, fleshy prey like fish and squid, using its slender ridged teeth to impale them.1

?Why did Acamptonectes have a stiff body?

Its stiff body helped it swim fast like a tuna by making it more streamlined in the water.1

Ask Rex about Acamptonectes

Rex only answers questions about this page. 3 questions a day.

Rex is an AI and can make mistakes. He runs on servers in the EU and questions are never saved. Never type your name or other personal things.

Myth buster

Myth: Many people think all ichthyosaurs went extinct at the end of the Jurassic.

Truth: Acamptonectes and other ophthalmosaurids lived well into the Cretaceous, showing no mass extinction at that time.2 1

For dino experts

Scientific name: Acamptonectes
Named by: Fischer et al. 20123
Group: Ichthyosaurs
Family / clade: Ophthalmosauridae3
Classification: Ichthyosauria > Ichthyosauromorpha3
Age of the rocks: 133 to 126 million years (Hauterivian)3
Rock formations: Speeton Clay3
Countries: United Kingdom, Germany3
Fossil records: 3 in the Paleobiology Database3
Discovery: Acamptonectes was named in 2012 by a team of scientists including V. Fischer, M. W. Maisch, and D. Naish. The first specimen was collected in 1958 by geology students in Speeton, England, but it took decades to study and describe.2 3
Still debated: Scientists are still debating whether Acamptonectes had a different diet or lifestyle from other Cretaceous ichthyosaurs because of its unusual shallow snout and tooth shape.1

Where the facts come from

Acamptonectes (en.wikipedia.org)
New Ophthalmosaurid Ichthyosaurs from the European Lower Cretaceous Demonstrate Extensive Ichthyosaur Survival across the Jurassic, Cretaceous Boundary (pmc.ncbi.nlm.nih.gov)
Acamptonectes 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.

Rex is hungry! Dino Wiki is a dad's project for his dino-loving son, free with no ads. Grown-ups can feed Rex a snack to help keep it online.Feed Rex