Paleontologists have uncovered the oldest known dinosaur footprints from Chile and the western margin of the ancient supercontinent Gondwana, shedding new light on dinosaur life in the Southern Hemisphere during the Late Jurassic period, around 160 million years ago.
The discovery was made in the Majala Formation in the Quebrada Huatacondo area of northern Chile, where researchers identified five distinct track-bearing levels. The study, led by Dr. Marko Yurac from the Unidad de Patrimonio Paleontológico and his colleagues, highlights a significant gap in the global dinosaur track record between Laurasia and Gondwana.
According to the researchers, the Late Jurassic fossil record in Europe and North America is comparatively rich, with numerous dinosaur track sites documented across countries such as Italy, Spain, France, Germany and Portugal, as well as extensive sites in North America.
In contrast, dinosaur tracks in Gondwana are far rarer and more fragmented, with only a handful of notable locations, including the High Atlas Mountains in Morocco and limited records from Australia and parts of South America.
In South America, most known Late Jurassic tracksites are concentrated along the continent's eastern margin, particularly in Brazil, Guyana and Uruguay, with some findings in Colombia. Until now, Chile was the only country along the western margin of South America to yield dinosaur tracks from this period.
The newly identified footprints were left by both theropod and sauropod dinosaurs during a time when northern Chile experienced alternating cycles of flooding and drought.
While the region was generally dry, seasonal water accumulation created short-lived wetlands that attracted dinosaurs of various sizes. As the animals walked across damp mud near these water sources, their footprints were preserved when subsequent flooding gently covered them with sediment.
The Majala Formation tracks reveal a wide range of theropod sizes, including giant footprints measuring over 50cm in length, large tracks measuring between 43.5cm and 46.5cm, and medium-sized prints of about 25cm to 27cm.
One surface contains more than 25 footprints from minute to small theropods, with lengths ranging from just 8cm to 13cm. Researchers noted that these are the smallest theropod footprints ever recorded in Chile, and possibly across the entire western margin of Gondwana.
Another surface at the site contains only sauropod tracks, although their poor state of preservation prevented precise measurements. Still, digital analysis suggests the presence of at least nine aligned footprints that may represent a trackway left by a large, long-necked dinosaur.
The researchers said the findings, published in the Swiss Journal of Palaeontology, provide crucial evidence for understanding dinosaur behaviour and the ancient environment of northern Chile during the Late Jurassic.
The footprints indicate that dinosaurs periodically occupied semi-arid floodplains and ephemeral wetlands, offering rare insight into how these animals adapted to changing climatic conditions.
