Ancient Animals Walked On Bird-Like Feet Over 210 Million Years Ago, Study Says

A study said that ancient animals were found to have walked on bird-like feet some 210 million years ago.

Researchers said that footprint morphology reflects the anatomy of the trackmaker's foot and it is a direct evidence for the animal's behavior. Consequently, fossil tracks can be used to infer ancient diversity, ethology, and evolutionary trends.

They said that this is particularly useful for deep-time intervals during which the early history of an animal group is reliant upon limited fossil skeletal material.

Findings Of The Study

According to the study, fossil tracks of early birds and theropods, the co-existing dinosaurian ancestors of birds, co-occur in the rock record since the Early Cretaceous. However, the evolutionary transition from dinosaur to bird and the timing of the birds' origin are still contested.

Experts said that the skeletal remains of the basal-most birds Aurornis, Anchiornis, Archaeopteryx and Xiaotingia are Middle to Late Jurassic, while tracks with tentative bird affinities, attributed to dinosaurs, are known from as early as the Late Triassic.

In the study, they presented numerous, well-provenanced, Late Triassic and Early Jurassic tridactyl tracks from southern Africa, with demonstrable bird-like affinities, predating basal bird body fossils by c. 60 million years.

Birds are one of the most diverse groups of animals on Earth with 10 000 extant species, yet their early evolutionary history is still shrouded in mystery. The dinosaurian origin of modern birds (Neornithes) unequivocally points to Maniraptora, a group of theropods, but the timing of the origin of birds is contested.

Studies have found out that the oldest body fossil record of basal birds comprises Middle to Late Jurassic (150-160 Ma) Aurornis, Anchiornis, Archaeopteryx and Xiaontingia, while dinosaurian footprints with bird-like morphologies are known since the Late Triassic.

Scientists said that the basal birds known from body fossils likely originated in the Early or pre-Jurassic, although, to-date, this is unconfirmed by the early osteological record that is exceedingly fragmentary.

Body Fossil

The only Late Triassic body fossil specimen posited to be bird-like is Protoavis, but this assessment is based on ambiguous material and is not widely accepted to be a basal bird.

In this context, all ancient bird-like paleontological discoveries are vital for unravelling both the origin of birds and the evolution of dinosaurs.

"It is likely that Morphotype II tracks were made by a yet-to-be-found tridactyl archosaur. That these tracks of southern Africa, dating to the Late Triassic, so strongly resemble Cenozoic and modern bird tracks substantiates the converging pedal morphology of Late Mesozoic archosaurs and firmly shows that the origin of bird-like foot morphology is at least 210 million years old,'' the study indicated.

Experts noted that it is possible that these tracks were produced by early dinosaurs, and potentially even early members of a near-bird lineage, but they further stated that there could also have been other reptiles, cousins of dinosaurs, that convergently evolved bird-like feet.

Whoever the trackmakers are, they said that these footprints establish the origin of bird-like feet at least as early as the Late Triassic Period.