| Top to bottom: A gastropod invertebrate paleontologists call scientifically, Ananias welleri; from the Stanton Limestone, Lansing Group, Missourian Stage--305.5 to 305 million years old. Bottom image--A gastropod that invertebrate paleontologists have assigned to the genus-species, Hypselentoma perhumerosa; from the upper Pennsylvanian Vilas Shale, Lansing Group of the Missourian Stage--305.5 to 305 million years old. 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. |