Protognathus
Protognathosaurus was a big, long-necked plant eater that lived in China during the Middle Jurassic. It is known from just a piece of its lower jaw, so scientists are still figuring out exactly what it looked like.1
When did it live?
How fast was it?
Fun facts
Protognathosaurus is known only from a single piece of lower jaw, called a dentary, which had about 18 tooth positions.1
Its name was first Protognathus, but that name was already used for a beetle, so in 1991 it was changed to Protognathosaurus.1
The jaw shows sharp replacement teeth still growing in, which is why the species name oxyodon means 'sharp tooth'.1
It lived about 168 to 161 million years ago, during the Middle Jurassic.1
The fossil was found in the Lower Shaximiao Formation, which is made of sandstone and mudstone from an ancient lake.2
Scientists think it was a medium-sized primitive sauropod, with a thick and heavy lower jaw.2
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Myth buster
Myth: Some people think Protognathosaurus is a fake or made-up dinosaur because it is so incomplete.
Truth: It is a real dinosaur, but many scientists consider it a nomen dubium, meaning the name is doubtful because the fossil is too fragmentary to be sure.1
For dino experts
- Scientific name
- Protognathus
- Named by
- Zhang 19883
- Group
- Long-necks
- Family / clade
- Cetiosauridae3
- Classification
- Sauropodomorpha > Sauropoda3
- Age of the rocks
- 171 to 155 million years (Bajocian / Oxfordian)3
- Fossil records
- 1 in the Paleobiology Database3
- Discovery
- In 1988, Zhang Yihun named and described the type species Protognathus oxyodon from a jaw found in China. In 1991, George Olshevsky renamed it Protognathosaurus because the old name was already taken.1
- Still debated
- Scientists debate whether Protognathosaurus is a valid genus or just a nomen dubium, because the only fossil is a piece of jaw.1
Where the facts come from
- Protognathosaurus (en.wikipedia.org)
- PBDB Taxon (paleobiodb.org)
- Protognathus 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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