Rare Allosaurus Dinosaur Rib Fossil Bone with Metal Stand, Morrison Formation, Upper Jurassic, Harding County USA

Description

Authentic Allosaurus Dinosaur Rib Fossil – Morrison Formation, South Dakota

This impressive Allosaurus rib bone fossil comes from the famous Morrison Formation in Harding County, South Dakota, USA, dating to the Upper Jurassic Period (approximately 150–155 million years ago). Mounted on a custom metal display stand, this genuine vertebrate fossil represents one of the most iconic carnivorous dinosaurs of the Mesozoic Era. The piece is an exceptional and scientifically valuable specimen — ideal for collectors, educational display, or museum-grade exhibition.

Geological and Palaeontological Context

The Morrison Formation is one of North America’s most celebrated fossil-bearing formations, extending across Colorado, Wyoming, Utah, New Mexico, and South Dakota. Deposited during the Late Jurassic, it records a dynamic landscape of floodplains, river channels, and shallow lakes, forming a perfect environment for preserving dinosaur remains.

The sediments, composed mainly of sandstones, mudstones, and silty clays, were laid down in a semi-arid floodplain system with seasonal rainfall. These deposits have yielded a remarkable assemblage of dinosaurs, including Allosaurus, Diplodocus, Stegosaurus, and Apatosaurus, offering an extraordinary window into Jurassic ecosystems.

This rib fossil shows the classic preservation typical of Morrison material — well-mineralised bone with excellent surface texture and detail. Its elongated, gently curved shape reflects the characteristic thoracic rib morphology of theropod dinosaurs, used to support the powerful chest cavity and facilitate deep breathing necessary for a large, active predator.

Allosaurus – Apex Predator of the Jurassic

Allosaurus, belonging to the family Allosauridae within the Theropoda order, was a formidable bipedal carnivore that dominated the Jurassic landscape of western North America. Growing up to 9 metres in length, Allosaurus had a massive skull equipped with serrated teeth, powerful hind limbs, and strong forelimbs armed with sharp claws for seizing prey.

This rib fossil is a rare piece of the skeleton of this fearsome predator. The rib bones of Allosaurus were long, robust, and slightly flattened, forming part of a deep chest that protected vital organs. The texture and curvature of this specimen are consistent with the anatomy of this genus, known for its combination of agility and strength. Its discovery within the Morrison Formation further confirms its authenticity and geological context, as Allosaurus is the most frequently encountered large theropod in these layers.

Display, Provenance, and Authenticity

The specimen is securely mounted on a metal display stand, allowing clear viewing of its natural curvature and bone structure. It presents beautifully as both a natural history exhibit and a collector’s centrepiece. The scale cube (1 cm) visible in the photo gives an accurate representation of size, and the photograph shows the exact specimen you will receive.

All of our fossils are 100% genuine specimens, carefully curated and authenticated by professional preparators. Each fossil is supplied with a Certificate of Authenticity, guaranteeing its provenance and scientific classification.

This Allosaurus rib fossil from the Morrison Formation embodies the power and history of the Late Jurassic world — a striking and tangible connection to one of Earth’s greatest prehistoric predators.