35% Oxygen Arthropleura T-Shirt Dinosaurs Make Me Happy when multicellular organisms rapidly diversified

when multicellular organisms rapidly diversified in form and function

featuring a beautifully illustrated orthocone nautiloid gliding through ancient seas teeming with early marine life

Highlighting the Pleistocene Epoch

Every shirt purchased plants a tree and is made with eco-friendly materials for a lighter footprint on the planet

35% Oxygen Arthropleura T-Shirt Dinosaurs Make Me Happy when multicellular organisms rapidly diversifiedThis vintage, distressed design highlights Arthropleura, the colossal millipede like arthropod that thrived in the Carboniferous Period, when atmospheric oxygen levels soared to around 35%. Rendered in detailed white linework against a deep black backdrop, the shirt blends natural history accuracy with bold paleo humor for an eye catching retro aesthetic. Made from 100% ring spun cotton (high quality cotton) with a soft, sensory friendly feel. Every