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Leptocleidus

Say it: lep-toh-KLY-dus

Name means: “slender clavicle”1

Ate: MeatPlesiosaursEarly CretaceousNot technically a dinosaur

Leptocleidus was a small plesiosaur that swam in shallow seas and rivers during the Early Cretaceous. It had a long neck, a short body, and four flippers to paddle through the water. Unlike many other plesiosaurs, it lived in lagoons and even brackish or fresh water.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

143 to 100 million years ago4

Early Cretaceous

Fossils found in

England (Sussex, Isle of Wight), South Africa (Cape Province), and Western Australia (Kalbarri)1

Food

Meat4 1

Length

up to 3 m1

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 Leptocleidus compared to YOU?

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cool stuff

Fun facts

Leptocleidus had about 21 teeth on each side of its upper jaw and around 35 teeth on each side of its lower jaw.1

Its skull was triangle-shaped with a crest running from the tip of the nose to the nasal region.1

Unlike many plesiosaurs, Leptocleidus lived in shallow lagoons and may have entered brackish or fresh water, like river mouths.1

Scientists think Leptocleidus moved into fresh water to escape larger plesiosaurs and pliosaurs.1

The name Leptocleidus comes from Greek words meaning 'slender clavicle', referring to its thin collarbone.1

Leptocleidus had large clavicles and interclavicle bones but small shoulder blades, similar to the early Jurassic Rhomaleosaurus.1

A specimen from the Isle of Wight, once thought to be Leptocleidus, was later named a separate genus, Vectocleidus, in 2012.1

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

?How big was Leptocleidus?

Leptocleidus was small for a plesiosaur, measuring up to 3 metres (9.8 feet) long. One species, Leptocleidus superstes, was even smaller at about 1.5 metres (5 feet).1 3

?Was Leptocleidus a dinosaur?

No, Leptocleidus was not a dinosaur. It was a plesiosaur, a type of extinct marine reptile that lived in the sea.1 3

?What did Leptocleidus eat?

Scientists are not sure exactly what Leptocleidus ate, but its many sharp teeth suggest it ate fish or other small sea creatures. It likely hunted in shallow waters.1 3

?Where did Leptocleidus live?

Leptocleidus lived in shallow lagoons and sometimes entered brackish or fresh water, like river mouths. Its fossils have been found in England, South Africa, and Australia.1 3

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For dino experts

Scientific name: Leptocleidus
Named by: Andrews 19224
Group: Plesiosaurs
Family / clade: Leptocleididae4
Classification: Plesiosauria > Sauropterygia4
Age of the rocks: 143 to 100 million years (Berriasian / Albian)4
Rock formations: Murderong Shale, Bulldog Shale, Weald Clay4
Countries: Australia, United Kingdom, South Africa4
Fossil records: 7 in the Paleobiology Database4
Also known as: Peyerus (older names now counted as the same animal)4
Discovery: Leptocleidus was named by Charles William Andrews in 1922 based on a partial skeleton and skull from the Weald Clay of Berwick, Sussex, England.4 1
Still debated: Scientists debate whether Leptocleidus belongs within the group Rhomaleosauridae or in its own separate clade called Leptocleididae.2

Where the facts come from

Leptocleidus (en.wikipedia.org)
Reassessment of the Lower Cretaceous (Barremian) pliosauroid Leptocleidus superstes Andrews, 1922 and other plesiosaur remains from the nonmarine Wealden succession of southern England | Zoological Journal of the Linnean Society | Oxford Academic (academic.oup.com)
Leptocleidus Facts for Kids (kids.kiddle.co)
Leptocleidus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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