Prehistoric Animal of the Week: Allosaurus

This week we're in the Morrison Formation of the Late Jurassic again to take a look at the lion of the Jurassic. Let's give a Jersey Boys welcome by pumping our fists for Allosaurus.

Allosaurus fragilis
Allosaurus, truly a "Different Lizard", was named by Marsh during the Bone Wars in the 1877. Allosaurus had a length of around 28 feet (8.5 meters) in length though larger specimens have been measured in at almost up to 39 feet (12 meters) in length. Allosaurus inhabited the western United States during the Late Jurassic from 155 to 150 million years ago. Allosaurus finds can be found in the Morrison formation commonly and also the Cleveland-Lloyd Dinosaur Quarry. Related finds can be found in Europe, indicating a possible related species from Portugal known as A. europaeus.

Allosaurus fragilis life restoration: Christopher DiPiazza

From the remains of Allosaurus, we can tell that Allosaurs may have hunted in packs, taking down larger prey like Barosaurus, Diplodocus, and even Apatosaurus. Other prey included early ornithopods, like Camptosaurus, and stegosaurids, such as Stegosaurus. Competition from other predators would have come in the form of Ceratosaurus. It's been suggested that Saurophaganax is a species of Allosaurus known as A. maximus, but the matter itself is heavily disputed. Many species have given for Allosaurus and therefore it makes the taxonomic history of this animal of heavy interest. There's even been suggestions of an Allosaurus from Australia as well. One thing is certain, Allosaurus is a very popular theropod.

Allosaurus skeletal mount at the American Museum of Natural History in New York.

References

Paul, G.S. "Princeton Field Guide to Dinosaurs". Princeton University Press. p. 94-96.

Join us next week as we venture off and take another look at a new animal. That does it for this week everybody, stay here at JBHD as we aim to educate you all about the prehistoric!