This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In 2014, members of a local museum found fragments of an ancient fossil dating to the end of the Pliocene or early Pleistocene epoch in a seaside cliff on the Argentine pampas. They belonged to a large predator, but the only group they fit, saber-toothed marsupial relatives, had supposedly gone extinct earlier, leaving the identity of the fossil a mystery.
That was until Eric del Campo, a paleontologist at the Argentine Museum of Natural Sciences in Buenos Aires and lead author of the study, and his colleagues took a closer look. The study, published in the Alcheringa: An Australasian Journal of Palaeontology, suggests the ancient bones may belong to a new species of saber-toothed predator called Pampaluctor calibar that survived long after the group it belonged to was thought to have disappeared. "Historically, it was believed that some native South American animals (both carnivores and herbivores) had lost to the more 'modern' northern ones when North and South America fully connected…" del Campo explained.
"The finding of Pampaluctor shows that native South American animals lived longer than previously assumed and interacted with the first 'northern newcomers.'" Sparassodonts were mostly meat-eating metatherians, the group that also includes modern-day marsupials, that lived in South America until they supposedly vanished by the mid- to late Pliocene. More than 50 species are known, ranging from small critters just under 3 kg (6.6 pounds) to giants weighing over 100 kg (220 pounds), rivaling even modern male jaguars. One group, the thylacosmilids, was among the most striking, known for their large, knifelike teeth much like those of saber-toothed cats, the researchers wrote.
When Pampaluctor was first discovered, no one knew what it was, but years later del Campo, a bachelor's degree student at the time, began to suspect it might belong to the supposedly extinct thylacosmilids. "Thylacosmilids were amazing animals with bizarre features, so having the opportunity to describe one is definitely a highlight," del Campo said. The partial skeleton included strong neck bones, a shoulder blade, various leg bones and two tail bones.
Researchers compared the bones to those of living and extinct species. While they resembled other thylacosmilids, they never quite matched, suggesting the researchers were looking at the remains of a new species. Based on its thigh bone, the animal would have been massive, weighing about 100 kg (220 pounds), possibly making it one of the largest known mammalian predators ever to have lived in South America, the authors wrote.
Meanwhile, its thick neck bones and heavily muscled front legs suggest it preferred to pin down its prey rather than chase it. "I would describe Pampaluctor as a strong ambush hunter, not particularly graceful, relying instead on overpowering prey with brute force rather than giving chase," del Campo said. Since no skull was recovered, the authors wanted the name to reflect the animal's powerful build, not its teeth.
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