Oldest birdlike footprints created by bipedal reptiles, analysis suggests
A new analysis of three-toed fossil footprints that date back more than 210 million years has revealed that they were likely created by bipedal reptiles with feet like a bird’s.
The footprints, found at several sites in southern Africa, were recently identified as the oldest birdlike tracks ever found, preceding the earliest known skeletal fossils of avians by about 60 million years, according to a study published in the journal PLOS ONE.
Dr. Miengah Abrahams, a lecturer in geological sciences at the University of Cape Town in South Africa and lead author of the study, stated that the footprints were likely made by dinosaurs, specifically a diverse group of bipedal meat-eaters with three-toed feet known as Theropods.
However, some of the newly examined dinosaur tracks differed from typical Theropod prints, with outliers displaying shorter extension of the central digit, a much wider splay, and significantly narrower toes, making them look more like the footprints of birds, Abrahams explained.
Despite the resemblance to birdlike footprints, it remains unclear whether the animals that made the tracks are related to birds or if they belong to reptiles that independently evolved birdlike feet.
The footprints, which were assigned the scientific name Trisauropodiscus by French paleontologist Paul Ellenberger, provide a missing clue about avian evolution and represent a significant find in the understanding of morphological diversification in the archosauria, an ancient reptile group that includes dinosaurs, pterosaurs, and crocodilians, according to Dr. Julia Clarke, a professor of vertebrate paleontology at the University of Texas at Austin.
The investigation into the footprints began in 2016, with the team creating 3D digital models of the footprints and reviewing a total of 163 tracks, which were divided into two morphotypes based on their shapes.
The Morphotype II tracks were found to closely resemble those of an avian from the Cretaceous Period and hint at the ancient origins of birdlike feet.
Overall, the study contributes to our collective ongoing understanding of the evolution of dinosaurs and birds, providing valuable insight into the early stages of avian evolution.
The researchers’ findings shed light on a previously unknown member of the archosaur group and the emergence of birdlike feet, adding to the growing body of knowledge about prehistoric life on Earth.
Reference: Abrahams et al.; 2023; PLOS ONE