Ordovician Trilobite Genera T-Shirt Mosasaurus fossil slightly distressed design with golden-yellow

slightly distressed design with golden-yellow linework and muted blue accents on a black background

Celebrate one of the most iconic dome-headed dinosaurs with our Pachycephalosaurus Born to Bonk T-Shirt

vintage field-guide style rather than any specific geologic period

every shirt is produced with environmentally responsible practices—and with each purchase

Its vintage

Ordovician Trilobite Genera T-Shirt Mosasaurus fossil slightly distressed design with golden-yellowArtist: ldn_rdnt_art The Ordovician was the final major period when trilobites greatly diversified, with very few completely new body forms appearing afterward. Most later trilobite evolution involved small changes to forms that had already developed during the Ordovician. By the time of the Ordovician mass extinction, trilobite expansion had ended, and their long decline had begun. This period represents the peak of trilobite variety in both shape