Timeline of therizinosaur research
The timeline of therizinosaur research is a chronological listing of events in the history of paleontology focused on therizinosaurs. They were unusually long-necked, pot-bellied, and large-clawed herbivorous theropods most closely related to birds. The early history of therizinosaur research occurred in three phases. The first phase was the discovery of scanty and puzzling fossils in Asia by the Central Asiatic Expeditions of the 1920s and Soviet-backed research in the 1950s. This phase resulted in the discovery of the Therizinosaurus cheloniformis type specimen. Soviet paleontologist Evgeny Maleev interpreted these unusual remains as belonging to some kind of gigantic turtle.
Reconstructed skeleton of the therizinosaurs Falcarius utahensis and Nothronychus graffami
Holotype claw cast of Therizinosaurus
Referred arms to Therizinosaurus by Barsbold
Erlikosaurus holotype skull and feet
Segnosaurus is a genus of therizinosaurid dinosaur that lived in what is now southeastern Mongolia during the Late Cretaceous, about 102–86 million years ago. Multiple incomplete but well-preserved specimens were discovered in the Gobi Desert in the 1970s, and in 1979 the genus and species Segnosaurus galbinensis were named. The generic name Segnosaurus means "slow lizard" and the specific name galbinensis refers to the Galbin region. The known material of this dinosaur includes the lower jaw, neck and tail vertebrae, the pelvis, shoulder girdle, and limb bones. Parts of the specimens have gone missing or become damaged since they were collected.
Right half of the holotype mandible in outer and inner view, with component bones marked by different colors; the dentary bone (green) bore the teeth.
Life restoration
Skull and foot bones of Erlikosaurus, which together with Segnosaurus (both from Mongolia) became the basis of the new infraorder Segnosauria; this group is now a junior synonym of Therizinosauria.
Therizinosaurus, the first known therizinosaur, was originally known only from forelimb bones from Mongolia (cast shown here, in Aathal Dinosaur Museum), which created confusion about its affinities with other theropods.