‘Remarkable’ petroglyphs found next to 145-million-year-old dinosaur footprints in Brazil

Paleontology and archeology have collided in northeastern Brazil after a ‘remarkable’ site containing dinosaur footprints and ancient petroglyphs was uncovered.

The Serrote do Letreiro site, in the municipality of Sousa, in the state of Paraíba, is home to three large rock outcrops, where the fossilized footprints of theropod, sauropod and iguanodont dinosaurs from the Early Cretaceous (145 to 100.5 million years ago) are discovers. Not only that, but the area is also home to petroglyphs – a type of rock art made by pecking directly into the rock surface – created by people in the pre-colonial period.

In a new study, researchers describe this “invaluable” intersection of paleontological and archaeological elements as never seen so close together.

Dinosaur tracks and petroglyphs have been found in association before – for example in Australia, Poland and Utah – but “in none of these cases do the petroglyphs show such a close relationship to the footprints as in Serrote do Letreiro,” the researchers write in their research.

“There is no question that the engravers recognized the footprints and deliberately executed the petroglyphs around them, creating a symbolic connection between human graphic expression and the fossil record.”

Petroglyphs and dinosaur tracks in Brazil

Petroglyphs and dinosaur tracks on Outcrop 1. Theropod footprints are in white and the engravings are in orange.

Image credit: Troiano et al., Scientific Reports, 2024 (CC BY 4.0)

The first records of dinosaur footprints from the region date back to the early 20th century, and the paleontological aspects of the site have been investigated several times in the years since. However, the petroglyphs have received much less attention, as they have never been extensively analyzed or considered in combination with the footprints.

To remedy this, the team surveyed the site and identified three large outcrops where both dinosaur footprints and petroglyphs were observed. An additional 22 symbols were discovered in the first digest, along with the highest concentration of theropod – the clade for which T. rex belongs to – tracks.

Footprints of Theropods

Theropod footprints (AF) in close association with petroglyphs (D and F).

Image credit: Troiano et al., Scientific Reports, 2024 (CC BY 4.0)

The second contained only two petroglyphs, although there appears to have once been a much larger number that have since become illegible. At the third and final outcrop, 30 carvings were identified, as well as extensive pecking marks and tracks left largely by sauropod dinosaurs.

The petroglyphs, the researchers found, are mostly circular with radial lines and other motifs. Although their meaning is not clear, they can be interpreted as geometric shapes and bear a striking resemblance to petroglyphs found elsewhere in Paraíba and Rio Grande do Norte. Some notable designs stand out, including rectangular grid carvings and others that resemble stars and snakes.

Petroglyphs

Petroglyphs from Outcrop 3.

Image credit: Troiano et al., Scientific Reports, 2024 (CC BY 4.0)

The variation in style suggests that multiple individuals were behind the petroglyphs. We may not know who they were, but we do know that they took great care in carving out the dinosaur footprints.

“In none of the cases was it found that creating a petroglyph resulted in damage to the existing footprints, indicating thoughtfulness on the part of the creators,” the team explains.

Serrote do Letreiro’s “excellent combination” of paleontology and archeology, according to the researchers, indicates that people in precolonial Brazil engaged with the fossil record, actively incorporated it into their graphic expression and used it to establish their cultural identity.

As such, the study authors advocate for its preservation and demand “immediate mitigation measures to prevent further damage” so that we can continue to appreciate this unique place for years to come.

The research has been published in Scientific Reports.

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