In a study published on November 29, 2023, in the open-access journal PLOS ONE, researchers Miengah Abrahams and Emese M. Bordy from the University of Cape Town, South Africa, reveal that ancient creatures were strolling around with bird-like feet over 210 million years ago.
Distinctive three-toed footprints known as Trisauropodiscus have been discovered at numerous fossil sites in southern Africa. The debate over the identity of the animals responsible for these tracks and the number of distinct Trisauropodiscus species has persisted for years.
The researchers conducted a thorough reassessment of the fossil record of Trisauropodiscus footprints, analyzing physical traces and published materials from four sites in Lesotho dating back to the Late Triassic and Early Jurassic Periods. The study also includes a detailed field-based description of footprints from an extensive tracksite in Maphutseng.
The findings reveal two distinct morphologies among Trisauropodiscus footprints. The first morphology resembles certain non-bird dinosaur tracks, while the second closely matches the size and proportions of bird footprints.
Although these footprints do not precisely match known fossil animals from the region and time, the oldest ones, surpassing 210 million years, predate the earliest body fossils of true birds by 60 million years.
While it is plausible that early dinosaurs or members of a near-bird lineage created these tracks, the researchers acknowledge the potential involvement of other reptiles, cousins of dinosaurs, that independently evolved bird-like feet. Regardless of the trackmakers' identity, these footprints establish the existence of bird-like feet as early as the Late Triassic Period.
The authors highlight, “Trisauropodiscus tracks are known from numerous southern African sites dating back to approximately 215 million years ago. The shape of the tracks is consistent with modern and more recent fossil bird tracks, but it is likely a dinosaur with a bird-like foot produced Trisauropodiscus.”
Source: Public Library of Science