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Alectrosaurus

Carnivore·Late Cretaceous·Iren Dabasu Formation, Inner Mongolia, China·Bipedal

Alectrosaurus is a genus of tyrannosauroid theropod dinosaur that lived in Asia during the Late Cretaceous period, approximately 96 million years ago. This medium-sized, bipedal carnivore was characterized by its elongated hindlimbs, suggesting it was a fast runner and a pursuit predator, filling a niche distinct from its larger, more robust relatives like Tyrannosaurus.

Key Facts

  • Alectrosaurus lived in Asia during the Late Cretaceous period.
  • It was a medium-sized, bipedal carnivore estimated to be 5 to 6 meters long.
  • Its elongated hindlimbs suggest it was a fast runner and a pursuit predator.
  • Fossils were discovered in the Iren Dabasu Formation in what is now China.
  • The genus name "Alectrosaurus" translates to "alone lizard" or "mateless lizard".
Alectrosaurus
Scientific Name
Alectrosaurus
Physical Characteristics

Medium-sized, moderately-built theropod., Elongated hindlimbs, suggesting speed., Femur and tibia subequal in length., Estimated length of 5 to 6 meters., Estimated weight of 454 to 907 kg.

Habitat
Floodplain environments with braided fluvial systems
Estimated Length M
5.5
Estimated Weight Kg
680
Dinosaur Group
Tyrannosauroid
Temporal Range
Late Cretaceous, approximately 96 million years ago (Cenomanian stage)
Named By
Charles Gilmore
Year Named
1933
Related Species

Tyrannosaurus, Albertosaurus, Gorgosaurus, Khankhuuluu Mongoliensis

Etymology
The generic name Alectrosaurus means "alone lizard" or "mateless lizard," derived from the Greek words 'alektos' (alone or unmarried) and 'sauros' (lizard). The specific name, olseni, honors George Olsen, the discoverer of the first specimens.
Fossil Record Quality
Fragmentary
Geographic Distribution

Asia

About Alectrosaurus

Alectrosaurus is a genus of tyrannosauroid theropod dinosaur that roamed the Earth in Asia during the Late Cretaceous period, approximately 96 million years ago. Its fossils have been unearthed in the Iren Dabasu Formation, a geological site now located in the Inner Mongolia Autonomous Region of China.

Physical Description and Lifestyle

Alectrosaurus was a medium-sized, moderately built, ground-dwelling carnivore that moved on two legs. It is estimated to have reached lengths of 5 to 6 meters (16 to 20 feet) and weighed between 454 to 907 kilograms (1,001 to 2,000 pounds). A distinctive feature of Alectrosaurus was its elongated hindlimbs, which differed from the more robust limbs of later tyrannosaurids. These proportions suggest that Alectrosaurus was a fast runner, likely filling the ecological niche of a pursuit predator, a role that appears to have been lost in more advanced tyrannosaurs.

Discovery and Naming

The first fossils of Alectrosaurus were discovered in 1923 by assistant paleontologist George Olsen during the Third Asiatic Expedition of the American Museum of Natural History, led by Walter W. Granger. The initial finds included a nearly complete right hindlimb and other bone fragments. The genus and species, Alectrosaurus olseni, were formally described and named by American paleontologist Charles Gilmore in 1933. The genus name, derived from Greek, translates to "alone lizard" or "mateless lizard," while the species name honors George Olsen.

Paleoenvironment

During the Late Cretaceous, the area where Alectrosaurus lived was characterized by a large floodplain with braided river environments and extensive vegetation. This ecosystem supported numerous herbivorous dinosaurs, including other theropods, a sauropod, and hadrosauroids. Alectrosaurus likely preyed upon these herbivores, playing a role in the food web of its time.

Source: Wikipedia ↗

Frequently Asked Questions

What does the name Alectrosaurus mean?

The name Alectrosaurus is derived from Greek words meaning "alone lizard" or "mateless lizard." This name reflects the Greek words 'alektos' (alone or unmarried) and 'sauros' (lizard).

When and where did Alectrosaurus live?

Alectrosaurus lived in Asia during the Late Cretaceous period, approximately 96 million years ago. Its fossils have been found in the Iren Dabasu Formation, located in what is now the Inner Mongolia Autonomous Region of China.

What did Alectrosaurus eat?

Alectrosaurus was a carnivore. Evidence suggests it likely preyed on herbivorous dinosaurs found in its paleoenvironment, such as Bactrosaurus and Gilmoreosaurus.

How large was Alectrosaurus?

Alectrosaurus was a medium-sized theropod, estimated to be between 5 to 6 meters (16 to 20 feet) in length. Its weight ranged from 454 to 907 kg (1,001 to 2,000 lb).

What made Alectrosaurus unique?

Alectrosaurus was distinguished by its elongated hindlimbs, which suggest it was a fast-running dinosaur. This anatomy likely allowed it to function as a pursuit predator, a role different from the more robust tyrannosaurids.