The first Abelisaurus fossil was found in Argentina in 1985 by Roberto Abel. This dinosaur was a fierce carnivore, but it evolved separately from the tyrannosaurs.
- The Abelisaurus had very powerful jaw muscles that could probably snap down quickly on prey.
- Scientists discovered a 3-foot long skull, but they still don’t know how large the largest Abelisaurus might be.
- The Abelisaurus belonged to the Theropoda group and lived during the Late Cretaceous Period.
See images of the Abelisaurus.
Imagine a dinosaur that was part stegosaur, part ankylosaur, and part porcupine. That’s the Agustinia dinosaur, named after Agustin Martinelli.
- Agustinia was discovered in Argentina in 1999.
- This plant eater is believed to have been 50 feet long and weighed 10 to 20 tons. It was a sauropod living during the Early Cretaceous Period, probably 115 to 110 million years ago.
- This dinosaur’s body was covered with bony lumps called osteoderms, which acted as armor. Along its back ran two rows of spikes, some as long as 29 inches. The spikes covered the dinosaur’s neck and tail too.
- Scientists have only found parts of the skeletons, rather than a whole fossil. They still have many things to learn about Agustinia.
Learn more about Augustinia.
Discovered in the US and Canada in 2007, the Albertoceratops was a theropod similar to a triceratops.
- Albertoceratops was well defended with two horns at the back of its head and two horns over its eyes. These horns would have protected its neck from predators like the tyrannosaurs.
- This dinosaur also had a bony frill around its neck.
- Albertoceratops lived on plants and was 16 feet long.
- It lived during the Late Cretaceous Period and belonged to the Theropoda group.
Find out more about Albertoceratops.
Albertosaurus was like a miniature version of its cousin, Tyrannosaurus rex. This predator hunted duckbills and horned dinosaurs.
- Albertosaurus was smaller than T-Rex. It had sharp teeth and an extra row of replacement teeth.
- This dinosaur had powerful back legs, but tiny arms and two-fingered hands.
- It was discovered in the USA and Canada in 1905.
- Albertosaurus belonged to the Theropoda group and lived during the Late Cretaceous Period.
Learn more about Albertosaurus.
Named after Don Gregorio Alvarez, the Alvarezsaurus was discovered in Argentina in 1991. Scientists have never found a complete skeleton, so we still have a lot to learn about this rare creature.
- The Alvarezsaurus is related to the ornithomimids, or ostrich-like dinosaurs, of North America.
- It was probably about 6 feet long, with long legs, feathered arms, and a feathered tail.
- It could run quickly, outpacing most of its predators, and likely ate lizards and other small animals.
- It lived during the Late Cretaceous Period.
See images of what scientists believe the Alvarezsaurus might have looked like.
We still have a lot to learn about this rare dinosaur, found in India in 1986. We know that it was probably an omnivore—an animal that eats both plants and meat—because it has both straight and curved teeth.
- Alwalkeria was named after Alick Walker.
- Scientists believe this dinosaur was small, growing only about 3 feet long.
- Its body resembled that of an allosaurus. It had powerful hind legs and short arms with clawed hands.
- It likely ate mostly insects, grubs, or reptiles, but consumed berries, seeds and plants when necessary.
- The Alwalkeria lived in the Late Triassic period and belonged to the sauropodamorpha group.
Watch a video about the Alwalkeria.
One of the smaller “long-neck” dinosaurs, the Amargasaurus was only 32 feet long. It also had two rows of spines on its neck and back. These spines might have been used for defense or to regulate the dinosaur’s temperature.
- Amargasaurus was discovered in Argentina in 1991.
- This dinosaur lived during the Early Cretaceous Period and was a plant-eating Sauropodamorpha.
Learn more about the Amargasaurus.
First found in the U.S. in 1818, the Anchisaurus’s name means similar lizard. This small, plant-eating dinosaur was only 8 feet long and probably weighed around 77 pounds.
- This dinosaur walked on its hind legs and had two small arms. It probably walked slowly, making it vulnerable to predators.
- When first discovered in Connecticut in 1818, scientists believed they’d found human remains. It wasn’t until 1885 that they realized the bones were those of a dinosaur.
- The Anchisaurus had slender feet, which was different from other sauropods. It lived during the Early Jurassic period.
Read about the Anchisaurus.
One of the few dinosaurs found in Antarctica, the Antarctopelta’s name means Antarctic shield. It lived during the Late Cretaceous Period and ate plants.
- Antarctopelta belonged to the Anklyosauria group.
- It had body armor made of bone and it was covered with many spikes.
- It appeared much later than other ankylosaurs.
See images of what Antarctopelta might have looked like.
This huge dinosaur might have been the largest animal on earth ever. It grew to 149 feet long and weighed more than 70 tons. At 70 feet tall, it could peer in a fifth story window.
- Argentinosaurus was discovered in Argentina in 1993.
- This huge sauropod ate plants.
- Only a few bones have been found and scientists are still learning about this giant.
Watch a video about the Argentinosaurus.
Found in Dinosaur Cove in Victoria, Australia, Atlascopcosaurus was named for the company that helped excavate the sea cliffs where it was discovered.
- Atlascopcosaurus was a small dinosaur—probably 10 feet long or less. This plant eater could probably run and hide from predators efficiently.
- Atlascopcosaurus might have lived in herds.
- It lived during the Early Cretaceous Period and its name means Atlas Corporation lizard.
Learn more about the excavation that brought us Atlascopcosaurus.
Part bird, part dinosaur, the Avimimus had long legs, a long neck, a beak, and feathers. Scientists believe it probably couldn’t fly although it was lightweight.
- This dinosaur lived during the Late Cretaceous Period (70 million years ago) and belonged to the Theropoda group. Its name means bird mimic.
- Avimimus probably ate both meat and plants, but had no teeth. It did have a beak and resembled a bird in other ways too. It had a long neck and a relatively small head. We don’t know if it had feathers, but it probably couldn’t fly.
- It was first found in Mongolia in 1981 and lived in a dry climate. It was first discovered by Russian scientists and later by Chinese scientists. Only three incomplete fossils have been found.
Read more about the rare Avimimus.
In 2000, a fossil was found in the U.S. of a young bird-like dinosaur. The fossil was almost complete, but scientists have never found others. Scientists know that this dinosaur had arms that could fold against its body like a bird. They also know that it had a relatively large brain and that it belonged to a group of feathered dinosaurs. Beyond that, they’re not sure. Some scientists think this dinosaur might not be a new discovery at all, but a different dinosaur.
- Bambiraptor means Bambi thief
- This dinosaur lived during the Late Cretaceous period.
- It was a meat eater, probably living on insects and small lizards and mammals.
- It was about 5 feet long.
See images of what the Bambiraptor might have looked like.
The Barosaurus was first discovered in the U.S. in 1890, but is one of the rarest of dinos. It’s similar to a Diplodocus but much longer. It had a small head and teeth and probably ate soft plants.
- Barosaurus means heavy lizard.
- The Barosaurus lived during the Late Jurassic period.
- It was 80 feet long.
- The Barosaurus is the rarest of the sauropods. Only two fossils are on exhibit in the world. One fossil contained a rare imprint of the animal’s skin, covered in scales.
Read more about this rare dinosaur.
Imagine a mix between a grizzly bear and a crocodile and you have a baryonyx. This dinosaur had a head shaped like a crocodile with a long snout, finely serrated teeth and a thin jaw. It moved on its back legs, using its front legs to swipe and catch fish like a bear might do. Its claws grew up to 14 inches long!
- The baryonyx’s jaws and teeth weren’t powerful enough to tear through large animals. It probably ate mostly fish. Fish bones have been found among the remains of this dinosaur and we know that England was covered with swamps and lakes at the time.
- Scientists believe it lived near the ocean. It was first discovered in England in 1986. It has also been found in what is now Spain and Portugal.
- Baryonyx’s name means heavy claw.
- It grew 30 feet long.
- It lived during the Early Cretaceous period, between 130 and 125 million years ago.
Read more about the Baryonyx.
This dinosaur was first discovered in Beipiao, China, which is where it gets its name. This birdlike dinosaur had a long neck and a small head. Although its teeth seem made for eating plants, scientists believe it was a meat eater. It had feathers and a bone structure similar to birds, but it could not fly.
- Beipiaosaurus was first discovered in 1999.
- It lived during the Late Cretaceous period, between 127 and 121 million years ago.
- It was a small dinosaur, probably around 7 feet in length.
Read more about the Beipiaosaurus.
Bonita means pretty in Spanish, but this dinosaur was named from the La Bonita quarry in Argentina where it was found in 2004. This large plant eater had many small teeth like the tines on a rake, as well as a hard cutting edge behind the teeth.
- Bonitasaura lived during the Late Cretaceous period.
- It grew 30 feet long and ate plants.
Read more about Bonitasaura.
This tiny dinosaur was only 11 pounds, about the size of a large Yorkie, and it grew 17 inches to 5 feet tall. It had a long snout and thin, small teeth for eating birds, frogs, insects, and small mammals. It could probably run quickly.
- Byronosaurus lived 80 to 75 million years ago in what is now Mongolia.
- It had large eye sockets, which might mean it was nocturnal. This makes sense since it lived in a desert terrain. Coming out at night would have been a smart strategy.
- Like modern birds, the Byronosaurus laid eggs in a cluster. The babies had very large eyes and small snouts.
Learn more about Byronosaurus.