Likewise, until now, the earliest known members of the dinosaur/bird branch were small, lithe, two-legged runners. But Teleocrater suggests that these animals were very specialized, and the group’s first representatives were slower, and moved on four legs.

From left to right: Christian Sidor, Sterling Nesbitt, Michelle Stocker, and Kenneth Angielczyk excavating Teleocrater. (Courtesy of Roger Smith)

This kind of information “will allow us to get at the really interesting questions, such as what features evolved in pterosaurs and dinosaurs that allowed them become successful,” says Irmis. “When did these features evolve, and did it have anything to do with the environments they lived in after the end-Permian mass extinction?” He’s talking about the greatest catastrophe in Earth’s history—the prolonged event that took place just before the Triassic period, which wiped out the vast majority of life on the planet.

The split between the croc lineage and dinosaur lineage happened shortly after, and the story has long been that the former dominated first. They were more widespread, richer in species, and more diverse in their body shapes. Indeed, the Triassic has been described as the “age of crocodilians.” The dinosaurs and pterosaurs had evolved, but they stuck to the sidelines, only taking center stage when another extinction event marked the end of the Triassic. But Nesbitt’s team thinks otherwise.

Their new discovery allowed them to reevaluate several other enigmatic Triassic weirdos, known from partial and piecemeal fossil remains. On their own, their bones provided few clues. But each is similar enough to a piece of Teleocrater that Nesbitt could confidently unite them into a single family—the aphanosaurs. They were clearly very widespread. Teleocrater lived in what is now Tanzania, Yarasuchus in India, Dongusuchus in Russia, and Spondylosoma in Brazil. “These things were probably everywhere,” says Nesbitt.

Other scientists have found similar patterns for several early dinosaur-adjacent groups, like the silesaurs and lagerpetids. “All these side-branches—these dinosaur relatives—were doing all the same things that dinosaurs eventually did. Again and again, they radiated and spread out across the world. The more we look in the Triassic sediments, the more we find them.”

This clearly shows that during the supposed “age of crocodilians,” the early members of the dinosaur bird lineage were also physically diverse, widespread, and successful. “It’s not that the dinosaurs suddenly took over,” says Stocker. “They and the croc lineage are both living together in the Triassic, and represent the same range of forms.”

Just last month, I wrote about another big paper that also relied on Triassic fossils. It showed that the first big fork in the dinosaur family tree, which has been the stuff of textbooks and museum exhibits for 130 years, might be wrong. As Lindsay Zanno, from the North Carolina Museum of Natural Sciences, told me, “If confirmed by independent studies, the changes will shake dinosaur paleontology to its core.”