Wisconsin: Calymene celebra (state fossil)
Wisconsin: Calymene celebra (state fossil)
Wisconsin's state fossil, the trilobite Calymene celebra, inhabited the reefs that flourished in the shallow seas that covered the state during the Late Ordovician and Silurian Periods, some 450 - 400 million years ago. At that time Wisconsin was about 30° south of the equator, and the coral reefs that were abundant in the warm seas were home to a teeming ecosystem of brachiopods, molluscs, and crinoids, as well as trilobites.
Trilobites were arthropods (related to insects and crabs), and as such, possessed a segmented body, jointed appendages, and an exoskeleton. Many types of trilobites could roll themselves up in a ball like a pill bug to protect their soft underbelly from predators. Calymene was a bottom-dweller that crept along the sea floor in search of food. Calymene itself lasted only until the end of the Devonian, and all trilobites went extinct at the end of the Paleozoic Era in the mass extinction that wiped out over 90% of the species on earth.
Calymene specimens are frequently found in limestones and dolomites in the southern part of the state, because glacial action has obscured fossil-bearing outcrops further north. The first Calymene fossils were collected by naturalist Increase A. Lapham in the 1830s and 40s. Since that time countless specimens have been unearthed along a swath of land from Prairie du Chien to Milwaukee.
After a trilobite bill failed twice in the legislature, the third time was the charm when Calymene celebra became the Wisconsin state fossil on April 2, 1986 with the signing of Act 162, Amended Section 1.1.
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