Therizinosaurus

Therizinosaurus was an enormous, highly unusual theropod that lived during the Late Cretaceous in what is now the Gobi Desert of Mongolia. When its first fossils were discovered, palaeontologists mistakenly interpreted its massive curved claws as the ribbed plates of an extinct giant sea turtle. Later discoveries of related therizinosaurs revealed that it was actually a towering, pot-bellied herbivorous dinosaur that walked primarily on two legs. Reaching an estimated length of ten metres and weighing several tonnes, it used its massive forelimbs and scythe-like claws to hook foliage down to its beak. Therizinosaurus likely bore a thick coat of primitive feathers, based on smaller relatives. While its skull remains undiscovered, it was almost certainly a plant eater with a small head perched atop a long neck.

It possessed manual claws measuring up to one metre long, the longest known of any animal.

Where and when

Therizinosaurus lived in the Late Cretaceous, from 70 to 66 million years ago (Maastrichtian age). Its remains come from Mongolia, in the Nemegt Formation.

The numbers

Length 9.5 m (estimates run from 9 to 10 m). Mass about 3.9 t. Hip height about 3.2 m. That is 5.6 human-lengths, or 0.85 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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