A recent study in 2025 has refined the age of fossils from East Kirkton Quarry in Scotland, offering new insights into early tetrapods. Led by Hector Garza from The University of Texas at Austin, the research focuses on fossils like Westlothiana lizziae, a crucial species for understanding the transition of life onto land.
Radiometric dating of zircon crystals in volcanic sediments around the fossils indicates they are approximately 341 million years old. This is older than previously thought, firmly placing them within Romer's Gap, a period with limited tetrapod fossils. The East Kirkton site has revealed a treasure trove of early tetrapods, including Silvanerpeton miripedes, Balanerpeton woodi, Ophiderpeton kirktonense, Eucritta melanolimnetes, and Kirktonecta milnerae.
The volcanic activity and unique chemistry of Lake Cadell contributed to preserving a diverse ecosystem, including early tetrapods, fish, arthropods, and plants. The refined dating helps calibrate evolutionary trees and understand the emergence of vertebrates on land. The study highlights the significance of the East Kirkton tetrapods in understanding vertebrate evolution.