Peruvian scientists unveil 10-million-year-old juvenile crocodile fossil found in Ocucaje desert

Peruvian paleontologists have unveiled the fossil of a juvenile marine crocodile dating back 10 to 12 million years, discovered in perfect condition in the Ocucaje Desert, a region recognized for its rich Miocene period fossils. The fossil was presented during the III Symposium - I International Congress of Paleontology of Peru, held this week in Lima.

The remarkable find consists of an almost complete articulated skeleton of the genus Piscogavialis, measuring approximately three meters in length. The skeleton includes the skull, jaws, limbs, and ribs, highlighting the exceptional state of preservation.

Clarín, El Universo, La República, and Science Alert reported on the finding, among other outlets. 

Paleontologist Mario Gamarra, a vertebrate specialist at the Geological, Mining and Metallurgical Institute of Peru (Ingemmet), led the reconstruction of the fossil. “This is the first time we found a juvenile of this species, that is to say, it had not reached its maximum size yet. It died before that,” Gamarra said during a news conference. He added, “We are only missing part of the left arm and a part of the tail,” while displaying the remains on a table.

The Ocucaje Desert, located approximately 350 kilometers south of Lima in the Ica region, is internationally renowned for its extraordinary abundance of fossils. The area has been the scene of outstanding discoveries for more than two decades, with the first indications of Miocene fossils found about thirty years ago. The desert has yielded remains of ancient whales, dolphins, sharks, and other species from the Miocene period, making it a treasure trove for paleontologists.

Gamarra emphasized the significance of this juvenile find in understanding the species' development and ancient marine ecosystems. “They had an elongated snout and their diet was completely piscivorous; they fed on fish and not so much on meat,” he explained. He noted that the closest current relative to this crocodile is likely the Indian gharial, which has an extremely long and thin snout.

The fossil's discovery was challenging due to its location in hard sandstone terrain. Gamarra described the preparation process: “The fossil came as a large block of rock and I took charge, with specialized tools, to work on it to leave it as it is now.” The extraction and subsequent preparation required nearly 80 hours of meticulous work.

The gharial crocodile fossil provides significant insight into the ancient marine ecosystems of the Peruvian coast, which was once part of an ancient ocean. Such discoveries help in understanding the evolution of marine fauna and reveal the adaptations and transformations that occurred over millions of years in marine crocodiles and their natural environments.

According to Ingemmet's statement, adult specimens of Piscogavialis could reach lengths of up to nine meters. “This is the possible Piscogavialis, a juvenile crocodile that inhabited the Peruvian coasts approximately 10 to 12 million years ago; as you can see, the skeleton is almost articulated and practically complete,” Gamarra said.

The collaboration between Ingemmet and Colegio La Unión was pivotal in the discovery and extraction of the fossil. Specialists from the Regional Geology Directorate of Ingemmet and students from the school assisted in the process.

The fossil will be exhibited to the public starting in December at Ingemmet's facilities located in the San Borja district of Lima. Gamarra indicated that they plan to continue studying the region to find more data about the life of this crocodile and its possible neighbors in the ancient sea.

This article was written in collaboration with generative AI company Alchemiq