The largest megaraptor discovered in Argentina

In March 2020, just a few days before the lockdowns in response to the Covid-19 pandemic were instituted in Argentina, a team of paleontologists led by the National Council for Scientific and Technical Research (CONICET) made an amazing discovery. In Estancia la Anita in the Province of Santa Cruz (an area located 1,677 miles from Buenos Aires), the experts found the bones of the largest megaraptor known to date. Measuring almost ten meters in length and weighing over five tons, Maip macrothorax was a fierce predatory dinosaur, roaming the territory of today’s Argentina about 70 million years ago, in the late Cretaceous Period.

This new species’ name was chosen by study lead author Alexis Aranciaga Rolando, a paleontologist at CONICET. According to Rolando, the name Maip “comes from an evil being from Tehuelche mythology who lived in the mountains and killed using the cold. Precisely, Maip’s finding took place in south El Calafate, from where the lavish Cordillera de los Andes can be seen, a place with very cold temperatures. Besides, for the Tehuelches, Maip represented the shadow that death leaves in its wake, while we imagine that during the Cretaceous, this great predator with its enormous size would have caused something similar.”

This dinosaur’s spine was made up of huge vertebrae, connected by a system of muscles, tendons, and ligaments allowing the massive creature to stand upright on its hind legs while walking or running. It had a long tail and legs, as well as enormous claws measuring 13.7 inches in length, which it probably used as its main weapons.

“The bones of Maip helped us to better understand the anatomy of megaraptors. They belong to a family whose skeleton was not like that of a tyrannosaurus, large but heavy, but rather light animals. In other words, their bones were not solid, but rather had a large number of internal voids that made them much lighter, something like a hollow brick compared to a solid one,” explained Rolando. 

According to the scientists, the area where Maip lived 70 million years ago – before the Andes mountain range had risen – was a warm ecosystem, with a variety of puddles, lakes, and streams that provided an optimal habitat for animals such as frogs, fish, turtles, small birds, and mammals. “From all those organisms that lived back then we were collecting fossil remains, and now, with Maip, we have added a super predator, which allows us to complete the food pyramid,” said study senior author Fernando Novas, a paleontologist at the Bernardino Rivadavia Museum of Natural Science in Buenos Aires.

Although the discovery of this dinosaur’s skeleton helps us shed more light on the features and behaviors of megaraptors not long before the catastrophic event from 66 million years ago that led to the extinction of the dinosaurs, many questions still remain unanswered.

“Megaraptors are quite enigmatic predators, and although Maip helped us to tie up several loose ends, especially their kinship relationships with other carnivorous dinosaurs, aspects of their hunting behavior still remain to be elucidated, for example what their favorite prey would have been, among other things,” concluded Rolando.   

The study is published in the journal Nature Scientific Reports.

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By Andrei Ionescu, Earth.com Staff Writer