Gastonia

Gastonia is one of the best understood early armoured dinosaurs, unearthed from the Yellow Cat Member of the Cedar Mountain Formation in Utah. Roaming North America during the Early Cretaceous, this heavily built plant-eater measured around five metres in length and weighed between one and two tonnes. Instead of a heavy tail club, Gastonia relied on an intricate array of defensive bone plates, triangular flank spines, and massive shoulder spikes. These lateral spikes projected outwards, forming a formidable barrier against large predators such as Utahraptor, which inhabited the very same ecosystems. The skull was heavily reinforced with thick dermal ossifications, and a continuous bony shield protected its sacrum and hips. Discovered in substantial bonebeds containing multiple individuals, Gastonia provides palaeontologists with valuable clues regarding the growth and herd behaviour of early ankylosaurians.

It possessed immense, blade-like shoulder spikes that fitted together like shears when the animal flexed its body.

Where and when

Gastonia lived in the Early Cretaceous, from 126 to 121 million years ago (Barremian age). Its remains come from United States, in the Cedar Mountain Formation.

The numbers

Length 4.8 m (estimates run from 4.5 to 5 m). Mass about 1.4 t. Hip height about 1.2 m. That is 2.8 human-lengths, or 0.43 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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