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A 7-Year-Old Boy Discovered T-Rex's Vegetarian Cousin

How Chilesaurus ditched steak for salad, and thrived because of it.
Concept art of what the dinosaur may have looked like. Image: Gabriel Lío

​When the duck-billed platypus was first discovered in 1798, its famously mismatched features led to a widespread rumor that the animal was a hoax.

Now, paleontologists have found the dinosaurian equivalent of the platypus—a turkey-sized vegetarian named Chilesaurus diegosuarezi, which roamed the southern region of Chilean Patagonia some 145 million years ago. This entirely new lineage of dinosaur is described in a study published Monday in Nature.


The remains of these dinosaurs were first found by a seven-year-old boy named Diego Suárez, after whom the species is named (talk about the ultimate childhood dream).

The fossils Suárez found represented several individuals, and they were so unusual that paleontologists initially assumed they must have originated from many different species. With its slender, arched neck and its small, beaked head, the animal looked disconcertingly like a cross between a long-necked sauropod and a krogan from the Mass Effect games.

Diego Suárez, the 7-year-old discoverer of the fossils. Image: Fernando Novas

On top of that, the species was determined to be part of the theropod clan, which is famous for producing all-star biped carnivores like T-Rex and Velociraptor. But Chilesaurus stood out as a rare theropod herbivore, distinguishing the animal as an early iconoclast in the family.

"Although plant-eating theropods have been recorded in North America and Asia, this is the first time a theropod with this characteristic has been found in a southern landmass," said paleontologist Fernando Novas, the lead author of the study, in a statement.

In addition, Novas pointed out that the exceptional condition of these fossils is a boon to reconstructing Chile's Jurassic ecology. "Chilesaurus is the first complete dinosaur from the Jurassic Period found in Chile and represents one of the most complete and anatomically correct documented theropod dinosaurs from the southern hemisphere," he said.


The discovery of these Chilesaurus individuals not only pushes back the timeline for when the theropod family tree first evolved herbivorous branches, it also provides paleontologists with one of the best examples of "mosaic convergent evolution" in the fossil record.

This process occurs when environmental pressures select anatomical features resembling unrelated species that occupy the same niche. In the case of Chilesaurs, it manifested as dental and vertebral features similar to long-necked sauropods, but integrated into the biped theropod body plan.

"Chilesaurus provides a good example of how evolution works in deep time and it is one of the most interesting cases of convergent evolution documented in the history of life," said study co-author Martín Ezcurra in a statement. "Chilesaurus shows how much data is still completely unknown about the early diversification of major dinosaur groups."

However odd the new dinosaur's juxtaposed features may seem, its unusual strategy ultimately paid off. According to Novas, the trove of Chilesaurus fossils discovered at Chile's Toqui Formation demonstrate that these evolutionary mashups were, by far, the most abundant dinosaurs in southwest Patagonia 145 million years ago.

It turns out that much like the platypus, Chilesaurus was sculpted into a bizarre bundle of convergent features by the pressures of its environment. By breaking with the meat-eating conventions of their family, Chilesaurs stumbled upon an entirely new niche to exploit, becoming yet another fascinating example of how, to quote Jurassic Park's Ian Malcolm, "life, uh, finds a way."