Therizinosaur facts for kids
Quick facts for kids TherizinosaursTemporal range: Cretaceous, 130–65.5 mya, possible Lower Jurassic record
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Maniraptoria
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Therizinosaurs (or segnosaurs) are a clade of theropod dinosaurs which appear to be herbivorous.
Therizinosaur fossils have been found in Cretaceous deposits in Mongolia, the People's Republic of China and Western North America. Various features of the forelimbs, skull and pelvis show they are theropods and maniraptorans, close relatives to birds.
History
Early finds were incomplete, and showed strange anatomy with features typical of theropods, prosauropods and ornithischians. This led some scientists to think that segnosaurs were a late-surviving suborder of primitive dinosaurs.
It was not until the mid-1990s, that their true identity as herbivorous descendants of the carnivorous theropods became generally accepted. Alxasaurus was discovered, and had more typical theropod features; and Therizinosaurus was recognized as a member of the segnosaur group.
The connection between the therizinosaurids and other theropods was made clear when primitive members of the group, such as Beipiaosaurus (1999) and Falcarius (2005) were discovered. The scientists who described Falcarius noted that it seemed to represent an intermediate stage between carnivorous and herbivorous theropods, a sort of "missing link" between predatory maniraptorans and plant-eating therizinosaurs.
Although they are now classified as theropods, therizinosaurs had skulls similar to those of sauropods and the shape of their teeth and jaws do make it likely that they were herbivores.
Images for kids
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Forelimbs of Therizinosaurus, specimen IGM 100/15 displayed at Nagoya City Science Museum
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Reconstructed pelvis and metatarsus of the holotype of Segnosaurus, which together with Erlikosaurus became the basis of the new infraorder Segnosauria; this group is now a synonym of Therizinosauria
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Reconstructed skeleton of Alxasaurus from China, the completeness of which confirmed therizinosaurs as theropods in 1993
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Partial forelimb of the basal therizinosaur Beipiaosaurus with impressions of feather structures, Paleozoological Museum of China
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Life restoration of Beipiaosaurus inexpectus
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Hips from different genera
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Skeletons of various genera (not to scale)
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Life restoration of an embryonic therizinosaur based on fossils from the Nanchao Formation
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Outdated restoration of a prosauropod-like, quadrupedal Erlikosaurus. Therizinosaurs were often depicted this way until they were definitively identified as theropods
See also
In Spanish: Therizinosauria para niños
