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Those Pesky Therizinosaurs!
Big-clawed dinosaurs called therizinosaurs puzzle paleontologists. These Cretaceous dinosaurs have left few fossils behind. Those fossils that have been found are incomplete and random: a lower jaw from one specimen, a hip from another... The first Therizinosaurus fossils found had arm bones with gigantic claws. So scientists thought it was a turtle-like creature not even related to dinosaurs! Since Alxasaurus is the most complete therizinosaur found so far, this species helps answer questions about the anatomy and evolution of all therizinosaurs.
Scientific Name: Alxasaurus elesitaiensis
Pronunciation: AHL-shah-SAW-rus eh-leh-SIT-ay-en-sis
Meaning: "Alxa Desert lizard"
Locality found: Alxa Desert, Inner Mongolia, China
Age: Early Cretaceous, 105 million years ago
Length: 4 meters (13 feet) long
Weight: 340 kilograms (750 pounds)
Characteristics: Like many herbivorous dinosaurs, Alxasaurus had a toothless beak and cheek teeth. Its diet, however, is not known.
In terms of its diet, Alxasaurus was:
a plant-eater or "herbivore"
a meat-eater or "carnivore"
no one knows
Correct!
It has some plant-eater features, like a beak and cheek teeth, but is closely related to meat-eaters. Alxasaurus is a mysterious dinosaur.
Therizinosaurs had feathers.
Fact
OR
Fiction
?
Fact
Beipiaosaurus from the Early Cretaceous period of China is an early therizinosaur. It is also the largest dinosaur found with traces of feathers.
Therizinosaurus had 2.5-meter-long (8-foot-long) arms with 69-centimeter (27-inch) claw bones.
Fact
OR
Fiction
?
Fact
In life, its actual claws were even bigger! That's because the nails aren't usually fossilized.