ScienceMiddle Devonian (~395 million years ago)Holy Cross Mountains, Polandhigh confidence

The ancient tetrapod footprints in Poland were found on a former marine tidal flat or lagoon in an abandoned mountain quarry, suggesting the evolution from fins to limbs occurred in an intertidal or lagoon environment rather than a seasonally flooded forest.

Notes on verification

Confirmed by peer-reviewed Nature paper (Niedźwiedzki et al. 2010) and corroborated by independent science journalism sources describing the tidal flat/lagoon depositional setting and its implications for tetrapod evolution timing and habitat. [tier=gold indep_score=0.95 clusters=3 claim_tier=notable]

Sources