New species of armless abelisaurus dinosaur discovered in Argentina

Abelisaurid ancestor?

The puzzle, including the upper and rear parts of the skull, was found in the Los Blanquitos formation near Amblayo in northern Argentina in rocks dating back 75 to 65 million years. This means that this animal lived just before the mass extinction at the end of the Cretaceous which saw the extinction of most dinosaurs.

A unique feature of this dinosaur are rows of small holes in the front of its skull called foramina. The researchers suggested that these holes could have allowed the animal to cool down, as blood was pumped through the thin skin at the front of the head to release heat.

Like many abelisaurids, the skull has a “remarkably small” braincase, but even then the new species has a skull about 70% smaller than any of its relatives. This reduced size may indicate that it is a juvenile, but there is conflicting evidence on this.

A similar lack of clarity extends to its other features, including thin skull parts and, unlike other abelisaurids, a lack of horns. It has been suggested that this could mean that the new species is near the bottom of the abelisaur family tree or closely related to the ancestors of the rest of the group.

Although some details are still unclear, there are enough unique features of the dinosaur to convince researchers that it is a new genus and species, which they named Guemesia ochoai. It is named after General Martin Miguel de Güemes, a hero of the Argentine War of Independence, and Javier Ochoa, a museum technician who discovered the specimen.

While many questions still surround the newly described abelisaurid, this adds to a growing body of evidence suggesting that northwestern Argentina had a unique set of creatures different from those found elsewhere in the world at that time. .

These include podocnemidoid turtles such as Stupendemys geographicusa die largest aquatic reptile have ever lived.

Scientists now hope to discover more specimens of Guemesia ochoai and his relatives to learn more about life in ancient Argentina. They particularly focus on the period just before and after the mass extinction at the end of the Cretaceous to understand how this massive event shaped life on Earth.

In addition to Guemesia ochoaithe team has already discovered several other interesting species, from fish to mammals, which they are currently describing.

Anjali explains that there is still a lot to learn from fossils in northern Argentina.

“Understanding huge global events like a mass extinction requires global datasets, but there are many parts of the world that have not been studied in detail and tons of fossils remain to be discovered,” she says.

“We left some exciting fossils in the ground on our last trip, not knowing that it would be years before we could return to our field sites. Now, we hope it won’t be long before we can finish digging them up and discover many more species of this unique fauna.

About Carlos V. Mitchell

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