Dilophosaurus facts for kids
Quick facts for kids Dilophosaurus |
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| Reconstructed cast of the holotype specimen (UCMP 37302) in position of burial, Royal Ontario Museum | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Neotheropoda |
| Genus: | †Dilophosaurus Welles, 1970 |
| Species: |
†D. wetherilli
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| Binomial name | |
| †Dilophosaurus wetherilli (Welles, 1954)
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| Synonyms | |
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Dilophosaurus (pronounced dy-LOH-fə-SOR-əs) was a type of meat-eating dinosaur called a theropod. It lived in what is now North America during the Early Jurassic period, about 186 million years ago. Its name means "two-crested lizard," referring to the two unique bony crests on its head.
Scientists first found three Dilophosaurus skeletons in northern Arizona in 1940. The best ones were collected in 1942. At first, it was thought to be a species of Megalosaurus. Later, in 1970, paleontologist Samuel P. Welles realized it had crests and gave it the new name Dilophosaurus wetherilli. The species name honors John Wetherill, an explorer. Other fossils, including a baby Dilophosaurus, have been found since then. Even fossil footprints are thought to belong to this dinosaur.
Dilophosaurus was one of the first large predatory dinosaurs. It was also the biggest land animal in North America at that time. It grew to about 7 meters (23 feet) long and weighed around 400 kilograms (880 pounds). This dinosaur was slender and built for speed. Its skull was large but delicate. It had a narrow snout with a small gap in its upper jaw. The two crests on its head were thin and arched. They were likely covered in keratin, which is the same material as your fingernails.
Its teeth were long, curved, and thin, perfect for slicing meat. The teeth in its lower jaw were smaller than those in its upper jaw. Dilophosaurus had a long, light neck with hollow bones. Its arms were strong, and its hands had four fingers. The first finger had a large, strong claw. The other two main fingers had smaller claws. Its legs were powerful, with strong feet and large claws on its toes.
Scientists believe Dilophosaurus was an active hunter. It probably hunted large animals, but might also have eaten smaller creatures and fish. The crests on its head were too fragile for fighting. They were likely used for showing off, perhaps to recognize other Dilophosaurus or to attract a mate. This dinosaur grew quickly when it was young. Some fossils show that Dilophosaurus had healed injuries, meaning it survived tough times. It lived alongside other dinosaurs like Scutellosaurus and Sarahsaurus. Dilophosaurus is even the state dinosaur of Connecticut, thanks to fossil footprints found there.
Many people know Dilophosaurus from the Jurassic Park movie. However, the movie version was smaller and had fictional abilities like spitting venom and a neck frill. The real Dilophosaurus did not have these features.
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Discovering Dilophosaurus
In 1940, a Navajo man named Jesse Williams found some fossil bones in northern Arizona. Two years later, in 1942, a team from the University of California Museum of Paleontology (UCMP) came to investigate. They found three dinosaur skeletons in purple rock. The area was near Tuba City on the Navajo Indian Reservation.
The first skeleton was almost complete, missing only parts of its skull and pelvis. The second had parts of its skull, jaws, and limb bones. The third was mostly gone due to erosion. It took two years to clean and prepare the best skeleton for display. Scientists had to rebuild parts of the skull and pelvis.
In 1954, paleontologist Samuel P. Welles described this dinosaur. He named it Megalosaurus wetherilli. The name honored John Wetherill, who helped explorers. At that time, many different theropods were grouped under Megalosaurus.
In 1964, Welles returned to Arizona. He found another, larger skeleton of the same dinosaur. This new fossil clearly showed two crests on its skull. This discovery was a big surprise! Welles realized the earlier specimens also had crushed crests. He also understood that the first two skeletons were younger, while the 1964 find was an adult.
A New Name for the Crested Dinosaur
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Because of its unique crests, Welles decided this dinosaur needed its own genus. In 1970, he named it Dilophosaurus. This name comes from Greek words meaning "two-crested lizard." Dilophosaurus was the first well-known large theropod from the Early Jurassic period. It remains one of the best-preserved dinosaurs from that time.
More Dilophosaurus fossils have been found since then. In 2001, scientists found parts of at least three new specimens. These included bones from a very young Dilophosaurus, one of the earliest known baby theropods in North America.
In 2020, paleontologists Adam D. Marsh and Timothy B. Rowe studied all known Dilophosaurus specimens. They helped clarify which parts were original fossils and which were reconstructions. This helped scientists understand the dinosaur's body better.
Other Dinosaurs Once Called Dilophosaurus
In 1993, a dinosaur from China was named Dilophosaurus sinensis. It also had two crests. However, scientists later found that this dinosaur was actually a different genus. It was renamed Sinosaurus. This shows how scientists sometimes change their minds as they learn more.
What Did Dilophosaurus Look Like?
Dilophosaurus was a medium-sized theropod, but it was very large for its time. It was the biggest land animal in North America during the Early Jurassic. It was slender and built lightly, similar in size to a brown bear. The largest known Dilophosaurus was about 7 meters (23 feet) long and weighed around 400 kilograms (880 pounds).
Some scientists have even suggested that Dilophosaurus might have had feathers. This idea comes from fossil footprints that show feather-like impressions around the belly and feet. However, other scientists think these might just be marks from the dinosaur moving in the mud.
Its Unique Skull and Crests
The skull of Dilophosaurus was large but delicate. Its snout was narrow. The front part of its upper jaw had a small gap, or "kink," behind the nostrils. This gap created a space in its tooth row.
The most striking feature was its pair of high, thin, arched crests on top of its head. These crests were made of bone. They were likely covered in keratin, which could have made them look even bigger. Scientists think these crests looked like the double crests of a cassowary bird. We don't know if the crests looked different between individual dinosaurs. CT scans show that the bones around its brain and in its crests had air sacs. These air sacs made the bones lighter and stronger.
Its eye sockets were oval-shaped. The lower jaw was slender at the front but much deeper at the back. It had a small opening on the side called the mandibular fenestra. The chin curved upwards.
Dilophosaurus had four teeth in the very front of its upper jaw, 12 in the rest of its upper jaw, and 17 in its lower jaw. The teeth were long, curved, and thin, perfect for slicing. They were flattened from side to side. The largest teeth were in the upper jaw. Most teeth had small serrations (like tiny saw blades) on their front and back edges. These serrations helped it cut through meat. The teeth were loosely held in their sockets. New teeth were always growing to replace old ones.
Body and Limbs
Dilophosaurus had a long neck with 10 neck bones (cervical vertebrae). Its neck bones were very light and hollow, with air sacs inside. This made its neck flexible. It had 14 back bones and 45 tail bones. The tail bones became smaller towards the end of the tail.
Its shoulder blades were wide. The arms were powerful, with strong muscles. The upper arm bone (humerus) was long and slender. Its hands had four fingers. The first finger was short but strong, with a large, curved, sharp claw. The next two fingers were longer and thinner, with smaller claws. The fourth finger was very small and likely had no use.
The hip bones were large. The hind legs were powerful. The thigh bone (femur) was massive and curved. It had strong feet with three well-developed toes that bore large claws. These foot claws were less curved than its hand claws. The first toe was smaller and stayed off the ground.
How Dilophosaurus Lived
What Did It Eat?
Scientists once thought Dilophosaurus had a weak bite because of the gap in its upper jaw. They believed it might have been a scavenger, eating animals that were already dead. However, other scientists argued that it was a strong predator. They thought its large neck and skull, along with its sharp teeth, were perfect for hunting big prey.
A study in 2005 suggested that the front of its jaw was used to catch and hold smaller prey. It might have delivered slashing bites to wound animals. Then, it would move the prey further back in its jaws to kill it with slicing teeth.
Some scientists also think Dilophosaurus might have eaten fish. Its jaw shape, with expanded ends and interlocking teeth, is similar to fish-eating crocodiles. Its nostrils were also set back on its jaws, which could help prevent water from splashing in while fishing. Its long arms and claws would also be useful for catching fish.
In 2018, scientists found possible tooth marks on the bones of another dinosaur, Sarahsaurus. These marks might have been left by a Dilophosaurus eating the carcass. This suggests Dilophosaurus could handle large prey, either by hunting or scavenging.
Newer studies in 2021 suggest Dilophosaurus had strong jaws, able to puncture bone. Its hollow bones, filled with air sacs, helped it breathe efficiently, like birds. This means it was likely a very active and agile hunter. Scientists now believe Dilophosaurus was an apex predator, meaning it was at the top of its food chain.
How Did It Move?
Dilophosaurus was an active dinosaur that walked on two legs, much like a large ostrich. Its powerful forelimbs were not used for walking. Instead, they were used for grasping and slashing. Scientists believe its hands could meet in front of its body and reach up its neck.
Studies of its arm movements show that its elbows could bend to a right angle. However, its wrists had limited movement. Its palms always faced inwards, towards each other. This is an ancient feature shared by many dinosaurs and birds. Its fingers could extend far back, which might have prevented them from dislocating when struggling with prey.
Because its arms were relatively short and had limited movement, its mouth likely made first contact with prey. It could use its arms to hold smaller animals close to its chest. Its long head and neck allowed its snout to reach further than its hands.
Fossil footprints, like those called Dilophosauripus, show how Dilophosaurus moved. These footprints were found in mud, showing flexible toes. Some scientists think that finding three skeletons close together, along with criss-crossing tracks, might mean Dilophosaurus traveled in groups. However, this is hard to prove.
A rare fossil trace shows a Dilophosaurus in a crouching position. It rested on its feet, metatarsals (part of the foot), and a padded area around its hip. This resting pose is very similar to how modern birds crouch. This trace also confirmed that early theropods held their palms facing inwards.
What Were the Crests For?
The exact purpose of the Dilophosaurus crests is still a mystery. Scientists have several ideas. They were too thin and delicate for fighting.
- Showing Off: Many scientists believe the crests were used for visual display. This could be to recognize other members of its own species. It might also have been to attract a mate, similar to how some birds use colorful feathers.
- Temperature Control: Some suggested the crests might have helped regulate body temperature, like a radiator. However, there's no clear evidence for this.
- Enlarged by Keratin: The crests were likely covered in keratin, which could have made them appear much larger and more impressive than the bone alone.
It is unknown if the air sacs inside the crests helped with these functions.
How Did It Grow?
Scientists initially thought the smaller Dilophosaurus fossils were young animals, and the larger one was an adult. Later, some wondered if differences in size might be due to differences between males and females. However, studies in 2005 found no strong evidence for this. Instead, the differences were likely due to individual variation and how the dinosaurs grew.
Studies of Dilophosaurus bones show that they grew very quickly. This dinosaur might have gained 30 to 35 kilograms (66 to 77 pounds) each year when it was young. This rapid growth helped it become a large predator quickly.
New teeth grew deep inside the jaw, replacing old ones. There were usually two or three replacement teeth ready at different stages of growth.
Signs of Past Sickness and Injuries
Scientists have found many signs of past injuries and bone problems in Dilophosaurus fossils. The original holotype specimen had several healed injuries. For example, one of its neck bones had a groove, possibly from an injury. Its left arm bones were smaller than its right, but its forearms were the opposite. This might have been a developmental issue.
In 2016, scientists found that the holotype had the most varied number of injuries on its shoulder and forelimb of any theropod dinosaur known. It had eight affected bones. These included a fractured shoulder blade and forearm bone, and bone problems in its ulna and thumb. On its right side, it had a twisted upper arm bone, three bony growths on its forearm, and a deformed third finger. This finger was permanently bent and could not flex. These deformities might have been caused by a disease called osteodysplasia, which is known in birds that suffered from poor nutrition.
These many injuries might have come from a single event, like crashing into a tree or rock during a fight. Since all the injuries had healed, the Dilophosaurus survived for a long time afterward, perhaps months or even years. Its ability to catch prey would have been affected during healing. It likely had to eat smaller prey or rely on one healthy arm.
These findings show that Dilophosaurus was a very tough animal. Scientists also noted that such injuries in dinosaur fossils are often overlooked.
Where Dilophosaurus Lived
Dilophosaurus fossils are found in the Kayenta Formation in North America. This rock layer dates to the Early Jurassic period, about 196–186 million years ago. The Kayenta Formation was a land of rivers and sand dunes. It was a seasonally dry environment, like a river oasis surrounded by sand.
Many other animals lived alongside Dilophosaurus. These included other dinosaurs like Megapnosaurus and Sarahsaurus, and the armored Scutellosaurus. There were also early crocodiles, pterosaurs (flying reptiles), and early mammals.
Dilophosaurus in Culture
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The Navajo people have traditional beliefs about fossils. They see them as the remains of ancient monsters. While Navajo people have helped scientists find fossils, some traditions suggest that disturbing these remains can be disrespectful.
In 2017, Dilophosaurus became the state dinosaur of Connecticut. This was because fossil footprints, thought to be made by a similar dinosaur, were found there in 1966. These tracks are called Eubrontes giganteus and are Connecticut's state fossil. The area where they were found is now Dinosaur State Park.
In 1998, a boy suggested Dilophosaurus as the state dinosaur of Arizona. However, lawmakers chose Sonorasaurus instead. This was partly because the Dilophosaurus fossils had been taken from the Navajo Reservation without permission.
Dilophosaurus in Jurassic Park
Dilophosaurus became famous after appearing in the 1990 novel Jurassic Park and its 1993 movie adaptation. The movie version of Dilophosaurus was quite different from the real dinosaur.
- Spitting Venom: In the story, Dilophosaurus could spit venom to blind its prey. This was a fictional ability created by the author.
- Neck Frill: The movie dinosaur also had a frill around its neck that expanded when it attacked. This feature was inspired by the frill-necked lizard. The real Dilophosaurus did not have a frill.
- Size: The movie version was shown as much smaller, about 1.2 meters (4 feet) tall. The real Dilophosaurus was about 3 meters (10 feet) tall at the hip.
The movie's creators admitted that the Dilophosaurus was the most fictionalized dinosaur in the film. Paleontologists have pointed out these differences. However, Samuel P. Welles, who named Dilophosaurus, was still "thrilled" to see his dinosaur become an "internationally known actor."
Images for kids
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Diagrams of fossil tracks from the Late Triassic-Early Jurassic, including Eubrontes (A), Dilophosauripus (E), and Kayentapus (F).
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Tracks attributed to Dilophosaurus in Glen Canyon National Recreation Area, Arizona.
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Cast of Coelophysis, a dinosaur often grouped with Dilophosaurus.
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Reconstructed skeleton of the crested Cryolophosaurus, sometimes considered a close relative of Dilophosaurus.
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Known skull bones of Dracovenator, which may have been a close relative of Dilophosaurus.
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Cast of a resting trace from Massachusetts, argued to have been made by a theropod like Dilophosaurus and to include feather impressions around the belly (arrow).
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Eubrontes resting trace of a theropod similar to Dilophosaurus.
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Map of the St. George Dinosaur Discovery Site with an Eubrontes trackway in red.
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Eubrontes tracks in Dinosaur State Park, Connecticut.
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More Eubrontes tracks in Dinosaur State Park, Connecticut.
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See also
In Spanish: Dilophosaurus wetherilli para niños
