How Dinosaurs Learned to Walk: Fossil Footprints Reveal the Evolution of Gait

Jan Bartek – AncientPages.com –

The research focuses on newly re-examined and newly described archosauriform footprints extracted from the GEOPARC Bletterbach UNESCO World Heritage Site in Italy’s Dolomites. Archosauriforms, the evolutionary precursors of dinosaurs and modern crocodilians, left these tracks. Previously, researchers grouped these trackways with Early Triassic footprints such as Protochirotherium and assumed that the animals already possessed an upright, columnar posture.

However, the team, which compared the morphology of the tracks with samples preserved at La Sapienza University in Rome and the Naturmuseum Südtirol in Bozen, determined that the footprints belonged to a distinctly new ichnofossil species: Pachychirotherium gardenaensis (meaning “thick-handed chirotheriid from Gardena”).

Physical measurements and limb proportions suggest that the tracks may belong to Erythrosuchidae or similar heavy-limbed archosauriforms.

Pachychirotherium gardenaensis gen. et sp. nov. holotype material. A–D, UR 75/2, holotype, right pes–manus pair, convex hyporelief: A, oblique top-lit photograph; B, oblique right-lit photograph; C, pseudocolor depth map; D, interpretive drawing. E–H, UR-NN 5, paratype, left pes–manus pair, convex hyporelief: E, oblique top-lit photograph; F, oblique right-lit photograph; G, pseudocolor depth map; H, interpretive drawing. All scale bars represent 5 cm. Source: Paleontology (2026). DOI: 10.1111/pala.70089

Researchers mapped the trackways extending from the Late Permian to the Middle Triassic, revealing a gradual, multi-stage evolution rather than an abrupt physical transformation. Their ancient ancestors in the Late Permian possessed a classic, sprawling posture, which gradually shifted until it became fully upright by the Middle Triassic. As their bodies adapted, the middle toes elongated to support a faster, more running-friendly gait, and the animals began walking on their toes rather than on flat feet.

Meanwhile, the systematic reduction in the size of the hands shifted the weight distribution and provided the biological foundation that enabled later dinosaurs to walk successfully on two legs.
As Dr. Marchetti noted, fossilized footprints offer valuable biological insights in cases where skeletal remains are rare, providing a direct, living record of prehistoric movement.

The research was published in the journal Palaeontology.