About Chilesaurus
| Scientific Name (Genus) | Chilesaurus |
| Meaning of Name | Chilean lizard |
| Classification | Dinosauria (formerly considered a theropod, but some theories suggest it is a basal ornithischian, still under debate) |
| Total Length | Approx. 1.6m (juvenile) - up to approx. 3.2m (adult) |
| Diet | Herbivorous |
| Period | Late Jurassic (approx. 148.7 - 147 million years ago) |
| Discovered in | Aysén Region, Patagonia, Chile, South America |
| Sub-classification / Species Name | Chilesaurus diegosuarezi |
| Year of Paper Publication | 2015 |
| Genus Name Publication |
An enigmatic plant-eating theropod from the Late Jurassic period of Chile.
Nature 522. by Novas, F. E.; Salgado, L.; Suárez, M.; Agnolín, F. L.; Ezcurra, M. N. D.; Chimento, N. S. R.; de la Cruz, R.; Isasi, M. P. et al. 2015. |
A Great Discovery by a 7-Year-Old Boy
The first fossil of Chilesaurus was discovered in 2004 in the Patagonia region of Chile, South America. The discoverer was surprisingly a boy named Diego Suárez, who was 7 years old at the time. Accompanying his geologist parents on a survey, he stumbled upon the bones of an unknown dinosaur while searching for pretty stones for decoration.
This discovery led to further excavations, and a large number of well-preserved fossils ranging from juveniles to adults were found from a single location. In 2015, it was officially described as a new species of dinosaur, and the specific name "diegosuarezi" was given in honor of the boy who was the first discoverer.
Chilesaurus - Perfect Adaptation to a Herbivorous Diet
Having lost the sharp teeth of carnivorous dinosaurs, it possesses leaf-like teeth for eating plants.
Chilesaurus had a small head relative to its body, and lacked teeth at the tip of its mouth. Instead, it had a bird-like beak, which is thought to have been used to pluck plants. In the back of the mouth, leaf-shaped teeth suitable for grinding plants were lined up. The jagged, sharp teeth for tearing meat seen in carnivorous dinosaurs were completely lost.
In addition, the shape of the pelvis was also special. The bone called the "pubis" points backward, a feature seen in "ornithischians" such as Stegosaurus and Triceratops. This is thought to be because it needed a wide space to accommodate a huge intestine in order to ferment indigestible plants over a long period.
The Bizarre Appearance Called the "Platypus Dinosaur"
The complete skeleton of Chilesaurus is in a "chimera" state, looking as if parts from various dinosaurs were thrown together.
The pelvis resembles that of "ornithischians" as mentioned above, but the thick, short front limbs have only two functional fingers like Tyrannosaurus, which is a characteristic of "theropods (carnivorous dinosaurs)". Furthermore, the wide foot structure that firmly supports its weight is very similar to early "sauropodomorphs (long-necked dinosaurs)", meaning it was completely unsuited for fast running.
Platypus Dinosaur: Because of its extremely bizarre appearance that combines the features of all three major dinosaur groups, it is compared to the platypus, a mammal with a bird-like beak, and is nicknamed the "platypus dinosaur" or "Frankenstein dinosaur" among researchers.
A Great Debate Shaking the Dinosaur Evolutionary Tree
Because of these bizarre features, exactly where Chilesaurus fits into the dinosaur family tree is still a subject of fierce debate.
Initially, it was considered under the old theory as an "extremely specialized theropod that coincidentally evolved a form similar to other dinosaur groups as a result of specializing in a herbivorous diet". However, a 2017 study proposed that Chilesaurus is the "most primitive ornithischian", retaining the shape of early evolution that had long been considered a missing link. This sent shockwaves through paleontologists worldwide as strong evidence supporting a new dinosaur family tree that groups theropods and ornithischians together into one large group called "Ornithoscelida".
The Surprising Origin of "Bird Wings" Told by Fossils
The fossils of Chilesaurus are incredibly well-preserved, and some were discovered in a "resting posture" with their forelimbs folded tightly against their bodies.
This mechanism of folding the front legs compactly is exactly like the structure current birds use to fold their wings. This suggests the possibility that the complex muscle and tendon mechanism controlling bird wings did not evolve for flying, but was originally created so that dinosaurs walking on land could store their long forelimbs tightly against their bodies to keep them out of the way.
Chilesaurus is considered not only to shake up the common sense of dinosaur classification, but also to be a time capsule for unraveling the mysteries of bird evolution.