Period: Late Cretaceous

Order, Suborder, Family: Saurischia, Segnosauria, Segnosauridae

Location: Asia (Mongolia)

Length: Unknown

In 1948, several giant claw bones were found by a Soviet-Mongolian scientific team in the Nemegt Basin of the Gobi Desert of Mongolia. Because the shape of the claws is similar to the claws of some turtles and because the claws were found with large, flat bones, workers first thought they belonged to a giant turtle. So the specimen was named Therizinosaurus cheloniformis ("turtle-like scythe reptile") by the famous Soviet paleontologist E. A. Maleyev.

Other finds of similar claws, including one with a partial arm, proved that the claws belonged to a dinosaur. The large, flat bones were not part of a turtle, but parts of sauropod ribs. The most interesting feature of these claws is their size. One bony portion of the claw is 28 inches long. In life, the claw would have been covered by hornlike material, making it even longer. It may be from a very large segnosaur.

Unfortunately, the remains of Therizinosaurus are too few, are not from parts of the skeleton that give much information (such as the skull or hips), and are in too many pieces to give scientists an understanding of its form and lifestyle. So it is not known what it looked like and what family it belongs to, but many paleontologists place it in Segnosauridae.

Scientists hope to find more fossils that will tell them more about the animal. Another large claw has been found in Niger, Africa, but it is not known if it is related to Therizinosaurus.