Dino card No. 1486 of 2,027

Protognathosaurus

Say it: PROH-toh-nath-oh-SORE-us

Name means: “early jaw lizard”1

Ate: PlantsLong-necksMiddle Jurassic to Late Jurassic

Protognathosaurus was a long-necked, plant-eating dinosaur that lived in what is now China during the Middle Jurassic. It is known only from a piece of its lower jaw, so scientists are still learning about it. Most researchers think it was a medium-sized sauropod.1 3

Lived

171 to 155 million years ago3

Middle Jurassic to Late Jurassic

Fossils found in

Dashanpu Dinosaur Quarry, Sichuan, China3 1

Food

Plants3 1 2

Length

10 to 100 m2

estimate from PBDB adult length category 10 to less than 100 metres (very uncertain)

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 22 cars parked in a rowas long as 560 bananas end to end

How big was Protognathosaurus compared to YOU?

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cool stuff

Fun facts

Protognathosaurus is known only from a single fossil: the front part of a left lower jaw, called a dentary.1

This dinosaur had 18 to 20 teeth in its lower jaw, and some of them were sharp replacement teeth still growing in.1 2

Its teeth had a sharp point and small serrations (like a steak knife) on the front and back edges.2

The name Protognathosaurus was first used in 1991 by George Olshevsky, because the original name Protognathus was already taken by a beetle.1

Most scientists consider Protognathosaurus a nomen dubium, meaning the fossil is too incomplete to be sure it is a distinct species.1

The jaw bone is thick and heavy, with a deep groove called the Meckelian canal, which is a feature of some early sauropods.2

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

?How big was Protognathosaurus?

Scientists don't know exactly, because only a jaw bone has been found. It was probably a medium-sized sauropod, maybe 10 to 20 metres long.1 3

?What did Protognathosaurus eat?

It was a herbivore, meaning it ate plants. Its sharp, serrated teeth helped it chew tough leaves.1 3

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For dino experts

Scientific name: Protognathosaurus
Named by: Olshevsky 19913
Group: Long-necks
Family / clade: Cetiosauridae3
Classification: Sauropodomorpha > Sauropoda3
Age of the rocks: 171 to 155 million years (Bajocian / Oxfordian)3
Rock formations: Shaximiao3
Countries: China3
Fossil records: 1 in the Paleobiology Database3
Discovery: The fossil was found in the Dashanpu Dinosaur Quarry in Sichuan, China. It was named Protognathus oxyodon by Zhang Yihun in 1988, but that name was already used for a beetle, so George Olshevsky renamed it Protognathosaurus oxyodon in 1991.1
Still debated: Scientists are not sure if Protognathosaurus is a valid dinosaur or just a doubtful name, because only a piece of jaw has been found.1

Where the facts come from

Protognathosaurus (en.wikipedia.org)
PBDB Taxon (paleobiodb.org)
Protognathosaurus 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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