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According to scientists, creatures resembling birds in their foot structure existed over 200 million years ago on Earth.
Analysis of ancient footprints, which experts were calling Trisauropodiscus, suggest these creatures were likely to have been three-toed.
The origin of the track marks is unknown, however, specialists suggest they could have been made by either a dinosaur or a reptile.
The results, which were published in the journal Plos One, suggest that bird-like feet developed much earlier than previously believed. This could provide insight into the origins of birds, possibly by as much as 60 million years.
The writers stated that there are 10,000 living species of birds, making them one of the most varied animal groups on our planet. However, their initial evolutionary past remains unclear.
A group of specialists from the University of Cape Town examined four sets of footprints discovered in Lesotho, located in southern Africa. They also investigated an 80-meter-long tracksite located in the village of Maphutseng.
The group discovered two different features within the footprint sets. The first was comparable to footprints of non-avian dinosaurs, while the second was similar in size and proportion to footprints made by modern birds.
The scientists suggest that these imprints may have been created by dinosaurs, although they acknowledge that they could also have been made by other reptiles that developed bird-like feet.
According to experts, the footprints are more than 210 million years old, making them 60 million years older than the earliest recorded fossils of actual birds.
The writers stated that there have been multiple discoveries of Trisauropodiscus tracks in various locations in southern Africa, with the oldest dating back to around 215 million years ago.
The shape of the tracks resembles those of modern and recent bird fossils, but it is possible that a dinosaur with bird-like feet created Trisauropodiscus.