Nepedia
Back to Discover
Advanced Reader
🧬

Parasaurolophus

life science Maturity 5-7 Next article →

Parasaurolophus is a famous genus of hadrosaurid dinosaurs. These animals are often called "duck-billed" dinosaurs. They lived during the Late Cretaceous period. This was approximately 76.5 to 73 million years ago.

Parasaurolophus walkeri
Parasaurolophus walkeri

They lived in western North America. Some evidence suggests they may have lived in Asia too. These dinosaurs were large herbivores. This means they ate only plants. They were quite big and heavy.

Parasaurolophus Scale
Parasaurolophus Scale

They could move in two ways. They could walk on four legs or run on two legs.

The most striking feature of Parasaurolophus was its cranial crest. This crest is a large growth on the back of the head. It is made of the premaxilla and nasal bones. The crest was hollow inside.

Parasaurolophus Cranial Crest
Parasaurolophus Cranial Crest

Inside the crest, distinct tubes ran from the nostrils. These tubes went to the end of the crest. Then, they reversed direction and traveled back into the skull. Scientists have several ideas about why these crests existed. One idea is acoustic resonance. This means they might have used the crests to make loud sounds for communication. Other theories suggest they helped with hearing or thermoregulation. Thermoregulation is the process of controlling body temperature.

There are three universally recognized species within this genus. The first is Parasaurolophus walkeri, which is the type species.

Parasaurolophus holotype skulls
Parasaurolophus holotype skulls

It has a relatively simple internal crest structure. The second species is Parasaurolophus tubicen. This is the largest of the three species. It lived in New Mexico. Its crest was long and straight. It also had a very complex interior of tubes.

Parasaurolophus walkeri
Parasaurolophus walkeri

The third species is Parasaurolophus cyrtocristatus. This is the smallest species. It had a short, rounded crest with a circular profile. Some scientists thought it might be a female of the other species. However, most studies now disagree due to differences in crest structure and age.

History shows how much we have learned about these animals. William Parks first described the genus in 1922. He used a skull and partial skeleton found in Alberta, Canada. He named the species P. walkeri after Sir Byron Edmund Walker.

Parasaurolophus holotype skulls
Parasaurolophus holotype skulls

In 1921, Charles H. Sternberg found a partial skull in New Mexico. This specimen was later described as P. tubicen by Carl Wiman in 1931. The name tubicen comes from the Latin word for "trumpeter." In 1961, John Ostrom described P. cyrtocristatus. Modern technology has also helped. Robert Sullivan and Thomas Williamson used computed tomography in 1999 to study the anatomy of the genus.

Parasaurolophus had a very specialized way of eating. They used a beak to crop plant material.

ParasaurCMNBeak
ParasaurCMNBeak

They had a cheek-like organ to hold the food in their jaws. Their teeth were arranged in dental batteries. These batteries contained hundreds of teeth. The teeth were constantly being replaced as they wore down. This allowed them to grind tough plants like leaves, twigs, and pine needles. They were likely browsers. This means they fed on vegetation at different heights. They could reach plants up to about 1 meter off the ground.

We can also learn about their growth from fossils. A juvenile specimen named "Joe" was found in the Kaiparowits Formation.

Parasaurolophus juvenile skeleton
Parasaurolophus juvenile skeleton

Joe was only about one year old when he died. This specimen is the youngest Parasaurolophus ever found. It was about 25% of the size of an adult. This helps scientists understand how they grew. It shows that their crests began to grow much earlier than in related dinosaurs like Corythosaurus. The skeleton of a large P. walkeri could reach over 10 meters in length. Some estimates suggest they weighed more than 2,000 kilograms.

Finally, we can see how Parasaurolophus fits into the wider world of dinosaurs. They belong to the hadrosaurid family. This family includes many diverse ornithopods. These dinosaurs are known for having many strange head decorations. Parasaurolophus is part of a specific group called the lambeosaurines.

Parasaurolophus walkeri
Parasaurolophus walkeri

Their closest known relative is Charonosaurus from China. Some scientists believe these two might form a group called Parasaurolophini. This connection shows how these dinosaurs might have spread across different landmasses during the Cretaceous period.

668 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (17)
File:Parasaurolophus walkeri.jpg
Parasaurolophus walkeri.jpg
File:Parasaurolophus holotype skulls.png
Parasaurolophus holotype skulls.png
File:Parasaurolophus_juvenile_DMNH_EPV_132300_skull.jpg
Parasaurolophus_juvenile_DMNH_EPV_132300_skull.jpg
File:Parasaurolophus Scale.svg
Parasaurolophus Scale.svg
File:ParasaurCMNBeak.jpg
ParasaurCMNBeak.jpg
File:Parasaurolophus walkeri.png
Parasaurolophus walkeri.png
File:Parasaurolophuspic steveoc.jpg
Parasaurolophuspic steveoc.jpg
File:Parasaurolophus juvenile skeleton.png
Parasaurolophus juvenile skeleton.png
File:Parasaurolophus reconstructed skeleton.png
Parasaurolophus reconstructed skeleton.png
File:Parasaurolophus Cranial Crest.svg
Parasaurolophus Cranial Crest.svg
File:Parasaurolophus skulls.jpg
Parasaurolophus skulls.jpg
File:The dinosaur book - the ruling reptiles and their relatives (1945) (20964204511).jpg
The dinosaur book - the ruling reptiles...

+ 5 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.