Two early relatives of modern crocodiles stood near each other among low ferns on a humid riverbank in northern New Mexico roughly 210 million years ago, according to researchers at Yale University. Each animal was roughly the size of a jackal, yet their physical remains indicate they hunted in distinctly different ways before dying together in a flash flood or mudslide and being preserved in rock blocks now housed at the Peabody Museum of Natural History at Yale.
Discovery of Eosphorosuchus lacrimosa at Ghost Ranch
Yale paleontologists identified the short-snouted animal in a newly published study as a previously unknown species named Eosphorosuchus lacrimosa. The fossil was originally excavated in 1948 from the Ghost Ranch Bone Bed in New Mexico, a site scientists have studied for about a century to examine near-crocodiles, lizard relatives, fish, and dinosaurs like Coelophysis bauri. Although available in museum collections for roughly 75 years, the two-meter-long blocks containing the specimens had not been fully analyzed until recently, according to Bhart-Anjan Bhullar, associate professor of Earth and planetary sciences in Yale’s Faculty of Arts and Sciences and senior author of the study published in Proceedings of the Royal Society B.
Did you know?
The Yale Peabody Museum holds sections of rock from the Ghost Ranch Bone Bed that together are roughly the size of a car, preserving a precise time-slice of the late Triassic Period.
CT Scans Uncover Hidden Anatomical Differences
To differentiate the specimens, Miranda Margulis-Ohnuma, a Ph.D. student in Earth and planetary sciences at Yale and first author of the study, analyzed computed tomography (CT) scans performed at the Yale Chemical and Biophysical Imaging Center by former Peabody Museum senior preparator Marilyn Fox. Digital disassembly of the fossil bone by bone revealed that while Hesperosuchus agilis featured a long, narrow snout and slender front limbs suited for running along rivers, Eosphorosuchus lacrimosa possessed a shorter snout, a heavily reinforced skull, and enlarged jaw muscles designed for snapping down on larger prey, according to the research team. Co-authors of the study include Alexander Ruebenstahl of Yale GSAS and Dalton Meyer, a recent Yale Ph.D. graduate now lecturing at Roanoke College.
Ecological Dynamics During the Late Triassic
During the late Triassic period, spanning 252 to 201 million years ago, early crocodile relatives and the lineage producing dinosaurs were expanding into new ecological roles. Bhullar noted that dinosaurs were slim, bipedal animals resembling herons, whereas early crocs operated as fast-running, four-legged predators comparable to jackals, big foxes, or dogs. The physical divergence between Hesperosuchus and Eosphorosuchus likely reduced direct competition by enabling the coexisting predators to target different types of prey in a shared habitat.
Frequently Asked Questions
What was Eosphorosuchus lacrimosa?
Eosphorosuchus lacrimosa was an extinct proto-crocodile identified by Yale University researchers that lived as a fast-running land predator near rivers and lakes approximately 210 million years ago.
Where were the fossils found?
The fossils were excavated in 1948 from the Ghost Ranch Bone Bed in northern New Mexico and are currently housed at the Yale Peabody Museum of Natural History.
How did researchers identify the new species?
Yale paleontologists used CT scans performed at the Yale Chemical and Biophysical Imaging Center to digitally disassemble the fossilized skull and identify unique anatomical features that differed from known Hesperosuchus specimens.
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