Skip to Content

Nothronychus

Nothronychus is a genus of herbivorous theropod dinosaurs that lived in North America during the Late Cretaceous period, around 94-89 million years ago. The type species, Nothronychus mckinleyi, was first described in 2001 by James Kirkland and Douglas G. Wolfe. This peculiar dinosaur had a long neck, a large claw, and a fuzzy coat of hair-like scales.

Nothronychus was an omnivorous dinosaur that may have even evolved from a carnivore to a herbivore. Its diet consisted of plants, fruits, and small animals. The discovery of Nothronychus raises questions about the diet of other maniraptoran dinosaurs, the ancestors of birds, and suggests that they may have also been herbivorous or omnivorous.

The fossils of Nothronychus have been found in various locations in the United States, including New Mexico and Utah. The study of Nothronychus and other therizinosaurid dinosaurs provides valuable insights into the evolution and diversity of dinosaurs during the Late Cretaceous period.

Taxonomy and Classification

Family and Genus

Nothronychus is a genus of therizinosaurid theropod dinosaurs that lived in North America during the Late Cretaceous period. It belongs to the family Therizinosauridae, which is a group of herbivorous dinosaurs that have been known to possess long necks, small heads, and large claws. The name Nothronychus means “slothful claw,” which refers to the large, curved claws that are present on the hands of this dinosaur.

Species Description

There are two known species of Nothronychus: Nothronychus mckinleyi and Nothronychus graffami. Nothronychus mckinleyi was the first species to be discovered and described by James Kirkland and Douglas G. Wolfe in 2001. It is known from the Moreno Hill Formation in west-central New Mexico, and is believed to have lived during the middle Turonian stage of the Late Cretaceous period. Nothronychus graffami was discovered later in south-central Utah and lived around 93 million years ago.

Nothronychus is classified as a theropod dinosaur, which is a group of bipedal, carnivorous dinosaurs that includes the well-known Tyrannosaurus rex. However, unlike other theropods, Nothronychus was an herbivore. It is believed to have fed on leaves, fruits, and other plant material using its sharp beak-like mouth and large, curved claws to grasp and pull down vegetation.

Overall, Nothronychus is an interesting dinosaur that provides insights into the evolution of theropods and the emergence of herbivory in dinosaurs.

Discovery and History

Nothronychus is a therizinosaur, a group of herbivorous theropod dinosaurs known for their long necks, small heads, and bird-like beaks. The first fossil evidence later attributed to Nothronychus was discovered by a team of paleontologists working in the Zuni Basin of New Mexico at the Haystack Butte site, Moreno Hill Formation. The fossils, consisting of a partial skull and postcranium, were found in 1998 and were described as a new species in 2001.

Fossil Record

Nothronychus fossils have been found in the Late Cretaceous rocks of North America. The two known species are Nothronychus mckinleyi and Nothronychus graffami. The former species is known from the middle Turonian Moreno Hill Formation in west-central New Mexico, while the latter species is known from the early Turonian Tropic Shale in south-central Utah.

Naming and Etymology

The name Nothronychus means “slothful claw” in reference to the animal’s large, curved claws, which were probably used for grasping vegetation. The specific epithet mckinleyi honors the McKinley family, who own the land where the fossils were found. The specific epithet graffami honors paleontologist and artist Michael W. Graffam, who contributed to the study of therizinosaur anatomy.

In conclusion, Nothronychus is a fascinating dinosaur with a unique appearance and diet. Its discovery and history provide insight into the evolution of herbivorous theropods and the Late Cretaceous ecosystems of North America.

Physical Characteristics

Anatomy

Nothronychus was a strange dinosaur with a unique anatomy. It had a bulky body, wide hips, and four-toed feet, all facing forward, similar to ornithischians. Its elongated neck and prominent arms had sharp claws, which were about 4 inches long. Nothronychus had a small head, a toothless beak, leaf-shaped cheek teeth, and a short tail. Although no feather imprints or fossils have been found, relatives of Nothronychus did have feathers.

Size and Weight

Nothronychus was a large dinosaur that could grow up to 15 feet long. Both species were similar in dimensions, but N. graffami was slightly more robust than N. mckinleyi. Nothronychus weighed around 1,500 to 2,000 pounds, making it one of the heaviest therizinosaurids.

Paleobiology

Diet and Feeding Habits

Nothronychus was an omnivorous dinosaur that lived during the Late Cretaceous period, around 94-89 million years ago. It is believed to have evolved from a carnivorous ancestor and transitioned to a herbivorous diet. This is supported by the presence of broad, leaf-shaped teeth that were adapted for grinding tough plant material.

In addition to plant material, Nothronychus may have also consumed small animals, such as insects and lizards. This is suggested by the presence of sharp, recurved teeth that were well-suited for catching and holding prey.

Locomotion

Nothronychus was a large, bipedal dinosaur with long legs that were adapted for walking and running. It is believed to have been a relatively fast runner, with a top speed of around 25-30 miles per hour.

Despite its large size, Nothronychus was also capable of climbing trees. This is suggested by the presence of curved, retractable claws on its hands that were well-suited for grasping onto branches.

Overall, Nothronychus was a highly specialized dinosaur that was adapted for a unique set of behaviors and ecological niches. Its unusual combination of traits make it a fascinating subject of study for paleontologists and dinosaur enthusiasts alike.

Habitat and Distribution

Nothronychus was a theropod dinosaur that lived during the Late Cretaceous period. It was primarily found in North America, with fossils discovered in Utah and New Mexico. Nothronychus lived in a variety of environments, including forests and floodplains. It was likely an omnivore, feeding on both plants and small animals.

The environment in which Nothronychus lived was characterized by a warm and humid climate. The region was also home to many other dinosaurs, including tyrannosaurs, ceratopsians, and hadrosaurs. Nothronychus was relatively large in size, measuring over 15 feet long, and had long arms with sharp claws that were likely used for defense or foraging.

Nothronychus fossils have been found in a variety of rock formations, including the Moreno Hill Formation in New Mexico and the Tropic Shale in Utah. These formations date back to the Turonian stage of the Late Cretaceous period, around 90-92 million years ago. The fossils provide important insights into the evolution and behavior of theropod dinosaurs and their place in the Late Cretaceous ecosystem.

Cultural Impact

In Popular Media

Nothronychus is not as popular as other dinosaurs like Tyrannosaurus, Triceratops, or Stegosaurus. However, it has still made appearances in popular media. It has been featured in the video game “Jurassic World Evolution” and the documentary “Dinosaurs Decoded”. In the video game, players can create their own Nothronychus and place it in their dinosaur park. In the documentary, scientists discuss the discovery of Nothronychus and its significance in the study of dinosaur evolution.

Scientific Significance

Nothronychus was the first definitive therizinosaur discovered in North America and currently represents the most specialized North American therizinosaurian genus. Its discovery provided important insights into the evolution of therizinosaurs, a group of herbivorous theropods that were previously known only from Asia. The discovery of Nothronychus also raised questions about the diet of therizinosaurs, as its teeth were not well-suited for slicing through tough vegetation. It is believed that Nothronychus may have used its large claws to pull down branches and strip leaves from trees, making it one of the few known herbivorous theropods.

Overall, Nothronychus may not be as well-known as other dinosaurs, but its discovery has provided valuable information about the evolution of therizinosaurs and the diversity of herbivorous theropods.