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Name means: Fused Reptile


Species: magniventris

Range: Late Cretaceous (Maastrichtian, 68-65 MYA) of Montana, Wyoming, and Alberta, Canada

Size estimate: 22 ft length, 6 tons

Discovery: Barnum Brown, 1908

Classification: dinosauria, ornithischia, thyreophora, ankylosauria, ankylosauridae


The largest and the last of the armored dinosaurs, Ankylosaurus is also the first known to science. Barnum Brown named the animal based on a complete skull, several backbones, a shoulder blade, and many armor plates. Scientists didn’t discover its bony tail club until a few years later. Ankylosaurus has so much armor that even its eyelids have bony plating. Its tail club consists of enlarged armor plating attached to a “handle” of fused tail bones. This design makes the club a more effective weapon against predators like Tyrannosaurus or Dakotaraptor.


For all its formidable armor, its jaws held teeth shaped like tiny saw blades. These teeth probably shredded fibrous plant material, though scientists don’t yet know its exact diet. The “big belly” part of its name refers to the stout shape of its skeleton. Its construction made room for a large gut full of bacteria that could digest tough plants.


Ankylosaurus lived alongside such famous dinosaurs as Triceratops, Pachycephalosaurus, Ornithomimus, and Tyrannosaurus.

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