Cretaceous

65 mya r

Were all dinosaurs the same?

No, they were not. There were lumbering animals as big as buses. There were long-necked giants as tall as trees. There were massive predators that none could challenge And darting around their feet were nimble chicken-sized dinosaurs. Some dinosaurs were numerous; others were rare. Some were plated, frilled, or horned; others were merely weird looking. Chindesaurus, shown here, was a carnivorous dinosaur that lived during the late Triassic Period. All the different dinosaurs belonged to one of two types.

Thick neck

Thick neck

Chindesaurus

Short arms for grasping prey

Chindesaurus

Short arms for grasping prey

Chindesaurus

What are the two main types of dinosaur?

The first dinosaurs evolved into two different types or orders, based on the shape of the hip bones. Ornithischians were bird-hipped and saurischians were lizard-hipped. The two orders gave rise to different families made up of genera. More than 540 different genera have been described so far.

IThe hips of ornithischians were characterized by a pair of bones (the pubis and ischium) that lay alongside each other and pointed backward.

Pubis

Ischium Ornithischian

Triassic Earth

Clawed feet

Clawed feet

Which was the most common dinosaur?

| A Experts can only estimate the answer to this question based on the numbers of fossil finds. So many skulls of Protoceratops have been found in the Gobi Desert that the dinosaur is sometimes called the "sheep of the Gobi." In North America, the remains of entire herds of duck-billed or hadrosaur dinosaurs have been unearthed.

Ischium Ornithischian

2 In saurischians, the pubis was larger and pointed downward and slightly forward, while the ischium extended backward.

Triassic Earth

Where did dinosaurs live?

Dinosaurs lived in every part of

Neck frill

Saurischian

the globe. However, when they first appeared, the world's land was a giant continent, known as Pangaea, which formed a C-shape around the Tethys Sea. Later, the landmass broke up into smaller continents. Dinosaur fossils have been found as far south as Antarctica, which was not covered with snow at that time.

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  • richard
    What were the types of dinosaur that they exist in the triassic period?
    9 years ago

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