Allosaurus

Allosaurus fragilis

The dominant predator of the Late Jurassic Morrison ecosystems, Allosaurus fragilis was a large theropod that reached roughly 9.7 meters in length, about 3.5 meters tall at the hip, and around 2,300 kilograms. Its skull carried distinctive horn-like ridges above the eyes, and its serrated, blade-edged teeth and powerful build suited it to tackling prey much larger than itself. Some fossil assemblages have been interpreted as pack hunting of sauropods, though cooperative behavior in the genus remains debated. Othniel Charles Marsh named it in 1877 from remains at Garden Park, Colorado, and it has since become one of the best-documented carnivores of the Jurassic, known from abundant material across western North America roughly 161 to 145 million years ago.

Allosaurus was the apex predator of the Late Jurassic, the lion of its age. It had a large skull with horn-like ridges above its eyes. Evidence suggests it may have hunted sauropods in packs.

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Physical Description

Measurement	Value	Human Scale
Longueur	9.7 m	roughly the length of a large SUV
Height	3.5 m	—
Poids	2.3 t	comparable to 2.3 small cars

Diet & Feeding

Carnivore

Allosaurus was a meat-eating predator. Carnivorous dinosaurs were active hunters or scavengers, equipped with sharp teeth and claws for catching and consuming prey. They occupied the top of the food chain in their ecosystems.

Time Period

Jurassic Late Mesozoic Era

Allosaurus lived during the Jurassic Late period of the Mesozoic Era, approximately 161,5 to 145,0 million years ago.

One of the most iconic periods for dinosaurs. Giant sauropods like Brachiosaurus and Diplodocus roamed alongside predators like Allosaurus. Archaeopteryx, the earliest known bird, appeared. The Morrison Formation preserves an extraordinary fossil record from this time.

Discovery & Naming

Nommé par	Othniel Charles Marsh
Année de découverte	1877
Lieu de découverte	Garden Park, Colorado, USA

Classification

Dinosauria → Saurischia → Theropoda → Allosaurus

Beast feet

Bipedal, mostly carnivorous dinosaurs that include the largest land predators ever to live. Theropods gave rise to modern birds. Ranges from tiny Compsognathus to massive Tyrannosaurus rex.