Two crocodile cousins died together on a riverbank 210 million years ago. One was already known to science. The other had been waiting in stone at Yale's Peabody Museum of Natural History until a team of paleontologists finally recognized it as something new.
The newly named species, Eosphorosuchus lacrimosa, was identified from fossils excavated at Ghost Ranch in northern New Mexico, one of the richest Late Triassic fossil sites in North America. The finding, published in the journal Proceedings of the Royal Society B: Biological Sciences, sheds new light on just how varied the early crocodile lineage had become before dinosaurs came to dominate the planet.
The two animals were roughly the same size, about as large as a jackal, and appear to have died at the same moment, likely from a sudden mudslide or flash flood. Their bones were preserved side by side within large blocks of rock, thanks to what researchers describe as fortunate geochemical conditions that held them in place across hundreds of millions of years. That kind of simultaneous preservation is rare, and it gave scientists unusual confidence that the two animals shared both a time and a place in life, not just in the museum.
The known species, Hesperosuchus agilis, had a long snout, large hind legs, and thinner forelimbs. It was a fast-moving land predator that hunted near water. Eosphorosuchus lacrimosa was built differently. It had a shorter snout, a more reinforced skull, and expanded jaw muscles suited for seizing and crushing larger prey. Despite their physical differences, the two appear to have occupied the same habitat, living side by side in what would have been a humid, fern-covered floodplain.
Bhart-Anjan Bhullar, associate professor of Earth and planetary sciences at Yale and senior author of the study, said the discovery speaks to a broader pattern of rapid diversification among early crocodile relatives during the Late Triassic. "During this period, there were two reptile dynasties vying for dominance: the line that would produce crocodiles and alligators on one side, and that which would produce birds, which of course are dinosaurs, on the other," he said. "The dinosaurs at this time were slim, delicate animals that walked on two slender legs almost like herons, and the crocodiles were fast-running, four-legged predators, low-slung and more heavily built."
Ghost Ranch has yielded dozens of fossil specimens over the years, including fish, lizard relatives, and the carnivorous dinosaur Coelophysis bauri. The site's exceptional preservation has made it a key location for understanding what life looked like in North America during the Late Triassic, roughly 210 to 220 million years ago, just as the first dinosaurs were beginning to appear.
Bhullar noted that reconstructing species diversity from such a distant past is rarely straightforward. Fossil evidence is fragmentary by nature, and paleontologists must often work with incomplete skeletons that may have been disturbed, scattered, or misidentified over time. Finding two individuals preserved together in articulated form removes some of that uncertainty. In this case, it also revealed that a specimen long held in one of the country's most prominent natural history collections had never been fully described.
The Peabody Museum at Yale holds one of the largest vertebrate paleontology collections in the United States, and researchers say cases like this are a reminder that significant discoveries can still emerge from existing collections rather than new field excavations. Eosphorosuchus lacrimosa had been sitting in storage, encased in rock, for decades before the current team took a closer look.
