| Top--Both sides of a pelecypod that invertebrate paleontologists assign to the genus-species Myalina (Orthomyalina) subquadrata, from the Scranton Shale, Wabaunsee Group of the Virgilian Stage (301-299 million years old). Bottom --Both sides of a pelecypod assigned to the genus-species Septimyalina perattenuata, from the Stranger Formation, Douglas Group of the Virgilian Stage--303 to 301 million years ago.. Images courtesy Pennsylvanian Atlas of Ancient Life Midcontinent United States, under terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. I edited and processed the photographs through photoshop. |