Page 29 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)

24 DINOSAURS REPTILES AND DINOSAURS 25

A Fierce Era Therizinosaurus THERIZINOSAURUS

Some scientists believe that this Therizinosaurus cheloniformis
he Cretaceous Period saw both the splendor and the end of the “Age of Reptiles.” It was the mysterious dinosaur was Size 39.5 feet (12 m)
herbivorous. However, it has been
longest period of the Mesozoic Era, and for 80 million years, specific types of animal life classified as a theropod that lived Diet Herbivorous (?)
T developed in each region. South America was home to the largest herbivore known, during the Late Cretaceous in the Habitat Subtropical Forests
region of the Gobi Desert in
Argentinosaurus huinculensis, which lived at the same time as the fearsome theropods. Some Mongolia. It was first identified in Epoch Late Cretaceous
species of this period later survived the mass extinction—especially marine invertebrates, such as 1954, and its name means “scythe Range Central Asia
lizard.” It was between 26 and 39.5
crustaceans, gastropod mollusks, and advanced ray-finned fish. Small feet (8-12 m) long and weighed about
mammals such as Zalambdalestes also survived. 5 tons (4.5 metric tons). It was AN ENIGMATIC DINOSAUR
believed to have possessed a lifestyle HEAD This dinosaur, one of the most perplexing of
similar to modern gorillas or the The head, atop a long all, has been identified by fossils of its claws
extinct giant ground sloths. neck, was small, and and a few other fragments that have been
it had a beak-shaped found. It is believed to share a common
The Struggle to Survive mouth. ancestor with the oviraptors. According to one
theory, it was an easy prey for predators such
Dinosaurs remained dominant during the giganotosaurs in South America were the largest threats as Tarbosaurus despite the size of its claws,
Cretaceous Period. Although the large sauropods to the peaceful herbivores. New, distinctive species, such which it probably did not use for defense.
still existed, new groups emerged, intensifying the as the duck-billed hadrosaurs and the armored
competition for resources. Enormous carnivores of the Triceratops, also appeared.
tyrannosaur family in North America and the
inches
40(1 m)
The size of one of the
claws on its front limbs
SUCHOMIMUS
means “crocodile imitator.”

Caudipteryx
was a feathered dinosaur that lived in China
in the early Cretaceous. It could grow up to
40 inches (1 m) in length and 27.5 inches (70
cm) in height. It was an advanced theropod,
but it looked like a large bird, because its ARMS
arms were covered with feathers and it had Its arms could measure up to 7.9 feet
an elaborate, fanlike tail. It had claws and a (2.4 m) long and were tipped with three
beak with sharp upper teeth. It could reach digits that ended in powerful claws.
great speeds when fleeing large predators.

CLAWS
CAUDIPTERYX Its most notable
means “tail feather.” characteristic was the
large claws on its front
Third Digit limbs, each of which could
measure up to 40 inches (1
Second Digit
Suchomimus Main Claw m) long. The claw on its first digit
was the longest of the three. It is
CORYTHOSAURUS
Similar to a crocodile, this dinosaur was a means “helmet lizard.” believed that it used its claws to pull
dangerous theropod that lived in northern large branches to its mouth.
Africa during the middle of the
Cretaceous Period. It could measure up COMPARISON OF SIZES
to 42.5 feet (13 m) long and 16.5 Corythosaurus
feet (5 m) tall. It had a long snout
with almost 100 teeth. was an ornithischian dinosaur of the hadrosaur family
with a showy crest. It could reach up to 33 feet (10 LEGS
m) long. It ate bushes and fruit in forests, and it lived Its lower limbs
in herds. The color of its crest may have been a had four small
distinctive feature if herds of different species claws.
intermingled. Its upper jaw had hundreds of small
teeth that were replaced often.
Suchomimus Caudipteryx Corythosaurus Therizinosaurus