December 8, 2023

Researchers have discovered a previously unknown species of a crocodile-like reptile that lived around 250 million years ago.

The new species belongs to an extinct group of animals known as Proterosuchidae, according to a study published in the journal Royal Society Open Science.

These ancient creatures superficially resembled crocodiles and likely lived similar lives. They were slender and had long snouts like crocs, though they lacked the armored scutes that are characteristic of these animals.

Proterosuchids were medium-sized reptiles, with the largest specimens measuring more than 10 feet long.

These animals lived approximately 255 to 245 million years ago and represent early members of a group called the Archosauriformes. This latter group includes crocodiles, dinosaurs (including birds) and several other completely extinct reptile groups.

“Proterosuchids were predatory, quadruped animals characterized by robust limbs that projected to the sides of the body, like a modern lizard,” Martin Ezcurra, paleontologist with the Bernardino Rivadavia Museum of Natural Science in Buenos Aires, Argentina, and lead author of the study, told Newsweek.

“They probably had semi-aquatic habits and an unusual feature of the proterosuchid anatomy is an oversized and downturned tip of the snout that possess multiple teeth. They lived in current day South America, Africa, India, Australia, eastern Europe and Asia,” he said.

A prehistoric reptile species, Samsarasuchus pamelae
An artist’s reconstruction of the newly described species, Samsarasuchus pamelae. The prehistoric creature belongs to an extinct group of animals known as Proterosuchidae, which were reptiles that superficially resembled crocodiles.
Gabriel Lio/Ezcurra et al., Royal Society Open Science 2023

Proterosuchids flourished on the supercontinent Pangaea following the devastating Permian-Triassic mass extinction event.

This extinction wiped out the majority of life on Earth and is considered by scientists to be the worst in our planet’s history. It occurred at the transition between the end of the Permian period (around 299-252 million years ago) and the beginning of the Triassic period (around 252-201 million years ago).

The event is thought to have resulted from an intense period of volcanic activity that spewed out vast quantities of greenhouse gases, ash and other debris. This led to significant global warming as well as other environmental effects such as ocean acidification.

While the extinction event caused devastation for life on Earth, many new groups of terrestrial animals—especially reptiles—flourished and diversified following the catastrophe over the course of the Triassic as biodiversity recovered.

In the latest study, an International team of researchers describe a newly identified species of proterosuchid, which they have named Samsarasuchus pamelae.

They were able to describe the new species after a reexamination of historical specimens and the collection of several new fossils from the Panchet Formation in eastern India—a geological assemblage containing rocks that date to the early Triassic. Several isolated proterosuchid bones have been reported from this formation previously.

Other proterosuchid species have been documented from the late Permian period in Russia and the early Triassic in South Africa and China.

Samsarasuchus pamelae is represented by most of the vertebrae of the neck and trunk, although researchers also identified several cranial, pelvic, limb and tailbone fossils that may also belong to the new species.

The researchers estimate that the animal measured around 5 feet in length and had a height of around 1.5 feet.

Samsarasuchus and other proterosuchids were predatory reptiles and probably fed upon other smaller vertebrates,” Ezcurra said. “However, it is possible that they also fed upon an animal of similar size called Lystrosaurus, which are distant forerunners of mammals.”

“It is probable that proterosuchids spent, at least, part of the day in shallow waters. It is not clear if proterosuchids were active hunters or not, but it is a possibility that they ambushed animals that got close to the coast of rivers.”

Samsarasuchus lived in a river delta where vegetation was scarce, according to Ezcurra. This environment was dominated by very few species that were survivors of the mass extinction event.

The latest findings provide new insights into the diversity of proterosuchids following the devastating mass extinction event, according to the study.

“The discovery of Samsarasuchus sheds light on the early evolution of the group of reptiles that subsequently gave rise to dinosaurs, crocodiles and pterosaurs,” Ezcurra said.

“It has allowed us to recognize robustly and using modern methodological techniques how and when the first diversification of these reptiles occurred after the end-Permian mass extinction. Thus, the new information allow us to understand better the aftermath of this dramatic biodiversity loss and how terrestrial ecosystems recovered,” Ezcurra said.