New fossils from Patagonia might rewrite the historical past of duck-billed dinosaurs


Fossils from the southern tip of Chile are including a wrinkle to researchers’ working out of ways duck-billed dinosaurs conquered the Cretaceous global.

Duck-billed dinos referred to as hadrosaurids had been extremely a hit and lived on maximum continents through the top of the Cretaceous, about 66 million years in the past. Now, a find out about displays that an older duck-billed lineage seems to have thrived some 72 million years in the past in subantarctic South The usa, probably hundreds of thousands of years prior to hadrosaurids reached the continent, researchers document June 16 in Science Advances.

“It’s but any other bankruptcy within the dispersion of those dinosaurs that we didn’t learn about,” says Jhonatan Alarcón-Muñoz, a paleontologist on the College of Chile in Santiago. 

A couple of decade in the past, paleobiologist Marcelo Leppe of the Chilean Antarctic Institute in Punta Arenas used to be on the lookout for plant fossils within the Río de las Chinas Valley in Chile’s Magallanes area when he noticed fossilized bones. After bringing the discovering to the eye of Alexander Vargas, a paleontologist on the College of Chile, researchers extracted the bones for find out about. 

Alarcón-Muñoz, Vargas, Leppe and their colleagues decided the bones belong to a brand new form of duck-billed dinosaur — herbivorous giants that had flattened, waterfowl-like snouts. The stays integrated many physique portions, with items of hip, limbs, ribs, vertebrae and cranium recovered. 

The researchers named the animal Gonkoken nanoi, “gon” and “koken” being the phrases for “very similar to” and “wild duck or swan” within the language of the Indigenous Aónikenk other folks from the a part of southern Patagonia the place the bones had been discovered. 

In all, the researchers suspect they discovered 4 distinct Gonkoken folks. No stays of different animals had been discovered with them, suggesting the dinosaurs had been most probably transferring in a herd, Vargas says (SN: 7/9/14). 

Gonkoken isn’t like different identified South American duck-billed dinosaurs, or like all from the outdated southern supercontinent of Gondwana, which integrated what got here to be South The usa. Till now, all identified duck-billed dinosaurs from Gondwana had been hadrosaurids, which had their heyday within the overdue Cretaceous and had such environment friendly, stacked, plant-pulverizing tooth that they chewed their solution to just about world dominance, outcompeting different herbivorous dinosaur teams. Gonkoken seems to be a part of an older, much less specialised lineage that diverged from different duck-billed dinosaurs round 91 million years in the past, prior to the primary hadrosaurids advanced, the researchers say. 

Gonkoken’s ducklike snout had a more practical building than that of hadrosaurids, Alarcón-Muñoz says, and it had fewer rows of tooth in its chewing floor. Gonkoken used to be additionally rather small — about 4 meters lengthy — whilst some hadrosaurids had been true titans, attaining about 15 meters in period. 

A 3D image of a skeleton reconstruction of a Gonkoken nanoi.
The three-D skeletal reconstruction of Gonkoken nanoi is created from scanning the unique, unearthed bones of the animal, along side bones reconstructed from different duck-billed dinosaur species.Francisco Hueichaleo

Seeing a non-hadrosaurid duck-billed dinosaur in South The usa like Gonkoken is “quite surprising,” says David Evans, a vertebrate paleontologist on the College of Toronto who wasn’t concerned within the analysis. The invention “makes us reconsider their biogeographic historical past within the Americas in attention-grabbing tactics.”

As an example, slightly than a unmarried colonization of the continent, the crew thinks that duck-billed dinos arrived in South The usa from North The usa in two separate waves. “We suspect our roughly duck-billed dinosaur arrived previous into South The usa and reached additional south than the hadrosaurids,” says Alarcón-Muñoz, describing Gonkoken as a relict. “In maximum different puts of the sector, this type of dinosaur had already long gone extinct through this time.”

The findings may additionally imply that hadrosaurids weren’t somewhat as standard as up to now idea. Fragmentary stays in southern Patagonia and Antarctica that had been idea to belong to hadrosaurids might in truth be Gonkoken or its shut family. 

Many different outcrops alongside the Río de las Chinas are studded with dinosaur bones. The researchers wish to read about those to look in the event that they belong to Gonkoken as smartly.  Discovering extra cranium bones of Gonkoken, Evans says, may well be key for working out precisely the way it used to be associated with different duck-billed dinosaurs. 

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