Britta Dal Formation
The Britta Dal Formation is a large terminal alluvial fan, triangular deposit of gravel, sand, and silt, with extensive mud-rich flood plains and sandstone beds found in East Greenland (Fig.1). There are intense vertisols, clay rich soils that indicate moisture change, present as well (Astin et al., 2010). The Britta Dal Formation is known for the tetrapod fossils of Acanthostega and Ichthyostega as well as others.
Figure 1: Location of the Britta Dal Formation in East Greenland. Modified from Marshall, 2020. Created by Kadie J. Steup (2023).
The Britta Dal Formation dates back to the Devonian period, which began about 419 million years ago and ended around 360 million years ago. The Britta Dal Formation is a late Devonian deposit, dating back to about 365 million years ago to the Famennian epoch (Astin et al., 2010).
Figure 2: Stratigraphic column highlighting the Britta Dal Formation, which is where Acanthostega is found, and its approximate age. Modified from Astin et al., 2010. Created by Kadie J. Steup (2023).
Acanthostega was found in the Britta Dal Formation meaning it lived about 365 million years ago (Astin et al., 2010). Along with other transitional tetrapods, Acanthostega lived in East Greenland most likely in shallow waters while occasionally propping itself on to land.
Living Environment
During this time period Earth was warm and the temperatures throughout the world was roughly equal. There was two supercontinents: Gondwana and Euramerica (Laurasia). A warm vast ocean covered the rest of the globe with diverse marine communities. You could most likely find Acanthostega in shallow weed choked swamps. Their limbs seem to be perfectly adapted for navigating through aquatic environments.
Figure : The world during the Late Devonian when Acanthostega lived. From Blieck et al., 2007.
Acanthostega was mostly aquatic and would rarley go on land except to possibly migrate from one body of water to the other (Janis et al., 1999). Acanthostega may have fed off the shoreline from time to time, but evidence suggests that it was feeding aquatically. Acathostega was a carnivore which suggests that it primarily been fed on fish(prehistoric-wildlife.com, 2015).
Figure : Size of Acanthostega as compared to a person. Modified from Prehistoric-wildlife.com, 2015. Created by Kadie J. Steup (2023).