The Ostrich-like dinosaur Limusaurus inextricabilis that lived in what is now China 160 million years ago has a unique trait. It is born with teeth but eventually become toothless as it gets older.

The creature was a two-legged dinosaur characterized by short arms and long, slender legs. The largest ones measured about 6 feet long or under 2 meters. Scientists believe they have down-like feathers that covered some parts of its body.

Most animals are born without any tooth and only developed them as they get older. Things are a little different with this bipedal dinosaur. They are born with chompers but eventually become toothless.

In a new study, scientists revealed that by the time these dinosaurs reach 3 years old, they already lost all of their pointy teeth and become toothless beasts for the rest of their lives.

Scientists reported that the fossils of 19 individuals belonging to this prehistoric species that range in age between less than a year old to 10 years of age revealed that the juveniles had small, sharp teeth but adults had toothless beak.

Loss Of Teeth Meant Change In Diet

The changes in the prehistoric creature's dental structure also changed their mealtime options. As a baby, these dinosaurs were likely omnivore or carnivores perhaps feeding on plants, insects and small vertebrates but they transitioned to becoming herbivores once they lost their pointy teeth.

Researchers found other evidences of the dramatic dietary change. The adults were found to have stones known as gastroliths that some herbivorous dinosaurs swallowed to help them grind up the plant materials in their stomach. The baby Limusaurus individuals lacked these. The researchers said the drastic changes may help shed light on why birds have toothless beak.

"This is important in showing that growth and development in dinosaurs was more complex than previously suspected, and it provides a model for a stage that birds may have gone through in evolving their beak," said George Washington University paleontologist James Clark.

Ontogenetic Edentulism

The tooth loss is what is known as ontogenetic edentulism. Some modern-day animals such as the egg-laying platypus still have it. Scientists think that the changes may have curbed food competition between juveniles and adults.

"Omnivory ensures a greater survival rate of immature individuals, and an ontogenetic dietary niche shift can reduce the competition for food between juvenile and adult individuals within a population," Clark and colleagues wrote in their study, which published in the journal Current Biology.

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