Agilisaurus
Herbivore·Middle Jurassic·Sichuan, China·Facultative Biped
Agilisaurus is a genus of ornithischian dinosaur that lived during the Middle Jurassic Period in what is now eastern Asia. The sole named species, A. louderbacki, is known from a remarkably complete skeleton discovered in Sichuan, China. This small herbivore was characterized by its agile build, leaf-shaped teeth, and potentially diurnal activity.
Key Facts
- ›Agilisaurus lived during the Middle Jurassic Period, approximately 168 to 161 million years ago.
- ›It was a small herbivore, measuring about 1.2–1.7 meters in length and weighing around 40 kg.
- ›The dinosaur possessed leaf-shaped teeth with wavy enamel, adapted for processing abrasive plant material.
- ›Its tibia was slightly longer than its femur, suggesting it was a fast bipedal runner, though it may have quadrupedally browsed.
- ›Fossils were discovered in the Lower Shaximiao Formation in Sichuan, China.
- ›Agilisaurus is considered one of the most basal members of the Euornithopoda group.
About 1.2–1.7 m In Length, 60 cm In Hip Height, 40 kg In Weight, Leaf-Shaped Teeth With Wavy Enamel, Long Legs and A Lightweight Skeleton, Tibia Slightly Longer Than Femur, Beak-Like Structure On Jaws
Hexinlusaurus Multidens
Asia
About Agilisaurus
Agilisaurus is a genus of ornithischian dinosaur that roamed the Earth during the Middle Jurassic Period. The sole known species, Agilisaurus louderbacki, is named after Dr. George Louderback, an American geologist who was the first to identify dinosaur fossils in China's Sichuan Province in 1915. The holotype specimen, a single, remarkably complete skeleton, was discovered in 1984 during the construction of the Zigong Dinosaur Museum, where it is now housed.
Discovery and Naming
The genus and species were formally named by Chinese paleontologist Peng Guangzhou in 1990 and described in more detail in 1992. The name Agilisaurus itself is derived from the Latin word 'agilis,' meaning 'agile,' and the Greek 'sauros,' meaning 'lizard,' a nod to the dinosaur's agile appearance due to its lightweight skeleton and long legs. The species epithet, louderbacki, honors Dr. George D. Louderback for his early work in Sichuan Province.
Physical Characteristics and Paleobiology
Agilisaurus was a small herbivore, estimated to be between 1.2 and 1.7 meters (3.9 to 5.6 feet) in length, with a hip height of about 60 cm (2.0 ft) and a weight of around 40 kg (88 lb). Its teeth were leaf-shaped and featured a unique wavy enamel structure, previously thought to be exclusive to later hadrosaurs, which aided in processing abrasive plant matter. The dinosaur's tibia was slightly longer than its femur, suggesting it was a fast bipedal runner that likely used its long tail for balance. While primarily bipedal, it might have adopted quadrupedal locomotion when browsing for food. Comparisons with modern animals suggest Agilisaurus may have been diurnal, active during the day, unlike some larger herbivores.
Classification
Despite the completeness of its fossil remains, the exact placement of Agilisaurus within the ornithischian family tree has been debated. It was initially placed in the now-invalid family Fabrosauridae. More recent cladistic analyses suggest it is one of the most basal members of the Euornithopoda group, which comprises more derived ornithopods. However, some studies have placed it in other positions, including as an ornithischian basal to both ornithopods and marginocephalians.
Fossil Context
The single known skeleton of Agilisaurus louderbacki was found in the Lower Shaximiao Formation, also known as the "Xiashaximiao" Formation. This geological unit preserves sediments from the Bathonian through Callovian stages of the Middle Jurassic, dating the dinosaur's existence to approximately 168 to 161 million years ago. The quarry outside Zigong, where Agilisaurus was found, has yielded fossils of other notable dinosaurs such as Xuanhanosaurus, Shunosaurus, and Huayangosaurus.
Source: Wikipedia ↗
Frequently Asked Questions
What does the name Agilisaurus mean?
The name Agilisaurus is derived from the Latin word 'agilis,' meaning 'agile,' and the Greek word 'sauros,' meaning 'lizard.' This name reflects the dinosaur's agile build, suggested by its lightweight skeleton and long legs.
When did Agilisaurus live?
Agilisaurus lived during the Middle Jurassic Period. The fossils are found in the Lower Shaximiao Formation, which dates from approximately 168 to 161 million years ago.
Where were Agilisaurus fossils found?
The fossils of Agilisaurus, specifically the holotype specimen of A. louderbacki, were discovered in Sichuan, China. They originate from the Lower Shaximiao Formation, near the site of the Zigong Dinosaur Museum.
What did Agilisaurus eat?
Agilisaurus was a herbivore. It possessed leaf-shaped teeth with wavy enamel, which were well-adapted for consuming abrasive plant material. Like other ornithischians, it had a beak-like structure on its jaws for cropping vegetation.
How large was Agilisaurus?
Agilisaurus was a relatively small dinosaur, estimated to be about 1.2 to 1.7 meters (3.9 to 5.6 feet) in length. It stood about 60 cm (2.0 ft) high at the hip and weighed approximately 40 kg (88 lb).
Was Agilisaurus a biped or quadruped?
Evidence suggests Agilisaurus was primarily a bipedal runner, indicated by its tibia being slightly longer than its femur, which would have allowed for speed. However, it may have also moved on all fours when browsing for food.
Related Dinosaur species
Abrosaurus
Abrosaurus was a genus of macronarian sauropod dinosaur that lived during the Middle Jurassic Period in what is now Asia. It is known for its relatively small size for a sauropod and its distinctive boxy skull with a prominent nasal arch. The only named species, Abrosaurus dongpoi, was discovered in China.
Baiyinosaurus
Baiyinosaurus is an extinct genus of stegosaurian dinosaur that lived during the Middle Jurassic period. Its fossils, discovered in Gansu Province, China, represent a partial skeleton including cranial and vertebral bones. Baiyinosaurus exhibits transitional features, displaying characteristics of both basal thyreophorans and more derived stegosaurs, making it a significant find for understanding the evolution of armored dinosaurs.
Bashanosaurus
Bashanosaurus is an extinct genus of stegosaurian dinosaur that lived during the Middle Jurassic period in what is now China. Known from incomplete skeletons, it is considered one of the earliest and most basal members of the Stegosauria, exhibiting a mix of ancestral and derived traits. Its discovery in the Shaximiao Formation provides important insights into the early evolution and diversification of plated dinosaurs.