In this week’s Trilobite Tuesday, we present a brief history of the ebb and flow of trilobite evolution. These amazing arthropods existed for nearly 300 million years of earth history, during which time they produced over 25,000 different scientifically recognized species. But the fact is that after presenting a dizzying array of species during the Cambrian, Ordovician and Silurian periods, by thetime the trilobite line reached the Devonian some 400 million years ago, their species count had dwindled down to a precious few. And by the time the Mississippian began, their was ostensibly only one order of trilobites left—the Proetids. Here is an attractive example of a “double” Ameropiltonia lauradanae from the Mississippian-age shale of Missouri. These proetids were among the last survivors of the noble trilobite lineage.
Learn much more on the Museum’s trilobite website,