🦕 Jurassic June #1: Allosaurus fragilis 🦕
Let's roll the clock back to the Jurassic, which lasted from roughly 201-145 million years ago. The ground trembles under the footsteps of giants that tower above the treeline. Large conifers and cycads cover the forests, and sprawling ferns line the forest floor. This is when birds first took flight. Back when the oceans were dominated by large reptiles beyond your wildest imaginations. This was a world far different from our own, ruled by dinosaurs large and small.
Welcome to Jurassic June! And what better way to start than one of the most iconic carnivores of this period, the majestic and fierce Allosaurus fragilis!
Allosaurus fragilis is the most common carnivorous theropod (group that includes T-rex, birds, etc.) dinosaur found in the Morrison formation, a rock layer from the Late Jurassic found in the Western United States. Described by one Othniel C. Marsh in 1887, the name Allosaurus is Greek for 'different lizard', a reference to its lightweight vertebrae which Marsh believed to be unique.
What I find even cooler, and funnier - is that the original fossil was discovered during something known as the Bone Wars, a long heated rivalry between two American paleontologists, the finder of the fossil Othniel Charles Marsh and Edward Drinker Cope. (I do wonder how much coping was involved)
A lot of iconic fossils were found because of a rivalry between two grown paleontologists, how awesome is that? This is all the reason I need for a Pokemon style paleontology game.
Allosaurus fragilis grew up to 8.5 metres in length (30ft), but it was not the largest predator of its time - we'll have a look at that in a later entry. As per the Natural History Museum of Utah, the skull of Allosaurus was structured in a way that allowed for it to have more teeth in contact with its prey.
Allosaurus fragilis had a full set of around 40-70 sharp and serrated teeth that were around 7.6 cm (3 inches) in length. They often lost teeth while hunting and regrew them throughout their lifetime. While not a speedster, the Allosaurus likely ran faster than some of the other large carnivores that existed alongside it.
Allosaurus fragilis had short horns in front of its eyes, most likely a mating display or a way to recognise other allosaurs. As for feathers, we don't know for sure as no direct evidence has been found. They also had strong arms that possibly helped with taking down prey.
There's a lot more to this dinosaur than I've told you about here, like the fact that some paleontologists argue it was a scavenger, a topic of hot debate. The arguments for this idea seem to be absence of a strong bite force, strong vision and the high availability of dead sauropods to feast on.
From what I can gather, the general consensus is that it was a highly opportunistic feeder - akin to modern lions, having the ability to hunt but preferring to save energy if possible. A last little fun fact to end off, the Allosaurus fragilis is one of the most deeply studied dinosaurs in Paleopathology - the scientific study of diseases and injuries in prehistoric species.
As always, additional information and corrections are welcome and highly encouraged. The prehistoric world is fascinating and I love learning about it and I hope you get some sense of the fascination I feel about dinosaurs by reading this! Follow for more posts like this one!
🔗Sources/Additional information:
Allosaurus fragilis - Dinosaur National Monument (U.S. National Park Service)
Natural History Museum of Utah - Allosaurus Fragilis
Fossilera - Allosaurus, the apex predator of the Jurassic
Allosaurus was predominantly a scavenger
New insights into the lifestyle of Allosaurus (Dinosauria: Theropoda) based on another specimen with multiple patholology
Jurassic Period Illustration - Spencer Sutto
Allosaurus fragillis skull,JPG - WIkipedia Commons
Final allosaurus image - Drawing an Allosaurus, Step by Step Smithsonian Magazine
