Zachelmie trackways

Morphological studies suggest that four-limbed vertebrates ("tetrapods" in the broad sense, also known as stegocephalians) are descended from a specialized type of tetrapodomorph fish, the epistostegalians.

[1] Crucial to this idea is the assumption that tetrapods originated in the Late Devonian, after elpistostegalians appear in the fossil record near the start of the Frasnian.

A reanalysis by Martin Qvarnström, Piotr Szrek, Per Ahlberg, and Grzegorz Niedźwiedzki, of the paleoenvironment of the Zachelmie trackways were reinterpreted as "a succession of ephemeral lakes with a restricted and non-marine biota, rather than a marginal marine environment as originally thought".

Daeschler said that trace evidence was not enough for him to modify the theory of tetrapod evolution,[10] while Shubin argued that Tiktaalik could have produced very similar footprints.

[2] However, a paper published in 2015 that undertook a critical review of Devonian tetrapod footprints called into question the designation of the Zachelmie marks and instead suggested an origin as fish nests or feeding traces.

[16][17] Narkiewicz, co-author of the article on the Zachelmie trackways, claimed that the Polish "discovery has disproved the theory that elpistostegids were the ancestors of tetrapods",[18] a notion partially shared by Philippe Janvier.