Nothronychus
| Nothronychus Temporal range: Late Cretaceous (Turonian)
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| Reconstructed skeletons of N. mckinleyi (right) and N. graffami (left) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Therizinosauroidea |
| Family: | †Therizinosauridae |
| Genus: | †Nothronychus Kirkland & Wolfe, 2001 |
| Type species | |
| †Nothronychus mckinleyi Kirkland & Wolfe, 2001
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| Other species | |
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Nothronychus (meaning "slothful claw") is a genus of therizinosaurid theropod dinosaurs that lived in North America during the Late Cretaceous period. The type species, Nothronychus mckinleyi, was described by James Kirkland and Douglas G. Wolfe in 2001. It was recovered near New Mexico's border with Arizona, in an area known as the Zuni Basin, from rocks assigned to the Moreno Hill Formation, dating to the Turonian stage of the Late Cretaceous. A second specimen, described in 2009 as a second species, Nothronychus graffami, was found in the Tropic Shale of Utah, dating to between one million and 500,000 years older than N. mckinleyi.
Like other therizinosaurids, Nothronychus was likely a bulky herbivore with wide, sloth-like hips (resembling those of the unrelated ornithischians), feet with forward-facing four toes, elongated necks, and prominent arms with sharp claws. Both species were similar in dimensions, but N. graffami was slightly more robust than N. mckinleyi.