Who owns these 210 million year old footprints?

Credits: M. Abrahams and EM Bordy, doi: 10.1371/journal.pone.0293021.

Tridactyl bird-like footprints discovered at the Maphutseng site in Lesotho are believed to be around 60 million years older than the oldest known bird body fossils. These tracks were made by an unknown animal, probably a primitive dinosaur.

When did the first birds appear?

The morphology of fossilized footprints directly reflects the anatomy of the foot of the organism that left the trace, thus providing tangible evidence of its behavior. Therefore, analyzing fossil footprints can infer information about the past diversity, ethology, and evolutionary trends of a species. This approach is particularly relevant for ancient periods of history where knowledge about an animal group often depends on limited fossilized skeletal material.

This is especially true for birds . We know in fact that their origin is undeniably linked to the theropod dinosaurs of the Maniraptora group. However, the precise date of their emergence remains a matter of debate.

In detail, the Middle to Upper Jurassic was a crucial period in the evolution of birds, marked by the appearance of the first fossil specimens around 150 to 160 million years ago . These fossils include representatives such as Aurornis, Anchiornis, Archeopteryx and Xiaotingia. These discoveries allowed scientists to identify primitive avian characteristics in these bird ancestors, shedding light on the earliest stages of their evolution.

Nevertheless, it is interesting to note that dinosaur footprints with avian morphologies are known from the Late Triassic . This suggests that long before the first bird body fossils appeared in the Middle Jurassic, some dinosaurs from that time had already developed anatomical features reminiscent of birds.

A track printed 210 million years ago

Scientists recently undertook a new analysis of footprint fossils collected from four separate sites in Lesotho that had initially been associated with the ichnogenus Trisauropodiscus. Particular attention was paid to the Maphutseng site where a track with a remarkable length of 80 meters was identified. This track included several tridactyl prints printed around 210 million years ago , suggesting a protoavian morphology characteristic of the Late Triassic and Early Jurassic.

The tridactyl prints discovered in this specific track offer clues to the anatomical features of the creatures that left them. These footprints are considered to have similarities to avian morphology , indicating that the dinosaurs responsible for these tracks may have developed anatomical features reminiscent of birds as early as the Late Triassic .

These findings also raise the possibility that these tracks were produced by early members of a lineage close to birds. However, other reptiles might also have convergently evolved to exhibit similar paw prints.