| A mostly complete Corynexochida trilobite from the lower Cambrian Harkless Formation, Extinction Canyon, Great Basin Desert, Nevada. Called scientifically, Protorytocephalus arcticus. Photograph courtesy Frederick A. Sundberg and Mark Webster. |
| A mostly complete Corynexochida trilobite from the lower Cambrian Harkless Formation, Extinction Canyon, Great Basin Desert, Nevada. Called scientifically, Protorytocephalus arcticus. Photograph courtesy Frederick A. Sundberg and Mark Webster. |