By Ellen Rykers

SAN FRANCISCO—The tip of bone sticking out of the dusty Patagonian earth was a tantalising hint: dinosaur fossil. Paleontologist Diego Pol and his team began to dig—unaware that they were about to unearth the largest dinosaur bone ever found.

This giant bone was just one of a series of sensational South American discoveries showcased by a panel of scientists on 28 October at the World Conference of Science Journalists 2017. Fellow Argentinian paleontologists Sebastián Apesteguía and Soledad Gouiric-Cavalli joined Pol to discuss their prehistoric findings for “Land of the Giants: South American Dinosaurs and Antarctic Secrets”.

Pol and his colleagues uncovered a monster-sized femur, 2.4 meters long and weighing 7 metric tons, that belonged to a long-necked, herbivorous behemoth dubbed Patagotitan mayorum. In total, the discovery site yielded more than 150 bones from six of these dinosaurs that roamed the continent during the Cretaceous, around 100 million years ago. This assemblage allowed researchers to estimate just how big they were.

“It was as long as a Boeing 737 and weighed about 70 tons. That’s equivalent to 10 African elephants,” said Pol, head of science at the Museum of Paleontology Egidio Feruglio in Trelew, Argentina.

Reaching such mighty proportions is no easy feat. Only a few times in Earth’s history have animals exceeded 10 tons, due to the substantial biomechanical and energetic requirements. At 70 tons, Patagotitan mayorum is the largest known terrestrial animal in Earth’s history.

South America is a “hotspot for dinosaur diversity and gigantism.”

Jumbo fossils like Patagotitan mayorum, combined with an understanding of ancient ecosystems, give researchers a window into how gigantism evolved.

But it wasn’t the only prehistoric giant to inhabit South America, described by Pol as a “hotspot for dinosaur diversity and gigantism.”

Apesteguía discussed finding huge fossilized footprints, belonging to the carnivorous theropod Giganotosaurus. These fearsome predators resembled the iconic Tyrannosaurus rex—but bigger. According to Apesteguía, they had a huge 2-meter-long skull, and their nose-to-tail body length exceeded T. rex’s by 3 meters.

Bad luck trailed the research team, including a flipped truck and an Indiana Jones–style heist.

Aside from ancient giants, there were also more compact prehistoric peculiarities in South America. Last year, Apesteguía published an account of the weird Gualicho dinosaur: a bipedal carnivore with two fingers on each hand and ridiculously tiny arms—the same size of those of a human child.

The dinosaur was named after a local demon spirit, Gualichu, because of the bad luck that trailed the research team, including a flipped truck and an Indiana Jones–style heist. “We suspended the field trip, and expected to return for the specimen the following year. But the dinosaur was stolen!” said Apesteguía, chief of paleontology at the Natural History Foundation Félix de Azara in Buenos Aires. After lengthy negotiations, Apesteguía’s team was eventually able to access the purloined specimen.

Apesteguía’s smaller-sized findings include “the most primitive snakes in the world” sporting tiny limbs, and a mammal with a pointy snout and fang resembling the squirrel-like character Scrat from the animated film Ice Age.

Discoveries of ancient fish

Not all the featured creatures were so wacky and unfamiliar to modern humans. Gouiric-Cavalli, palaeontologist at the National University of La Plata in Buenos Aires, shared her discoveries of ancient fish. Today, she said, fish are one of the most successful animal groups on Earth. But fish also traversed the oceans as far back as 400 million years ago, and represent an important step in the evolution of tetrapods.

Gouiric-Cavalli described arriving at the museum to find a disorganized pile of Jurassic rocks. Out of this geological chaos, she uncovered a fossil fish “beautifully preserved” in three dimensions—an occurrence she said was “quite unusual.” This specimen (Jonoichthys challwa), related to modern needlefish, and other endemic specimens investigated by Gouiric-Cavalli are reshaping theories about the origins and migration routes of prehistoric fish.

Journalist Federico Kukso led the lively session, highlighting the exotic discoveries by the three paleontologists. These Argentinian scientific ambassadors—both researchers and fossils—can fly under the radar of journalists outside Latin America. After this session, that is sure to evolve.

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Ellen Rykers is a freelance science journalist based in New Zealand. When not putting pen to paper, she’s studying toward a master’s degree in Science Communication at the University of Otago and traveling the world in her hiking boots. Follow her on Twitter @ellerykr