Scottish fossils push land-walker origin into Romer’s Gap by 14 million years
New uranium-lead dating of zircons from the East Kirkton site in Scotland places Westlothiana lizziae and related stem tetrapods inside Romer’s Gap, with a central age of 341 ± 3 million years and oldest grains around 346 Ma—roughly 14–15 million years older than previous estimates and about 14 million years older than the traditional timing for the water-to-land transition. This provides a tighter timing framework for when vertebrates first began to move onto land, but does not explain why the transition occurred or fully resolve Romer’s Gap.
