THE OFFICIAL DINO LAND WEBSITE STATE FOSSILS
Over the course of geological time Wisconsin has been home to billions of species of intriguing lifeforms, from early arthropods to dinosaurs to the recent mammoths and musk ox, which only yesterday disappeared from the state's fertile plains. Unfortunately, the most recent Ice Age, including the major glaciation which bears Wisconsin's name, has wreaked havoc on the Dairy State's fossil record. Most of the central and northern parts of the state are nearly barren of fossils, instead being filled with thick layers of glacial till. But, not the southern region. The area of Wisconsin extending from Prairie du Chien in the west to the urban center of Milwaukee on the shores of Lake Michigan in the east are chock full of fossils, including a beautiful trilobite now known as the state fossil.
About 420 million years ago much of the state of Wisconsin was covered by a large shallow sea. This warm body of water was a haven for life, and was home to several species of crinoids, brachiopods, corals, and trilobites. One of these trilobites was Calymene celebra, a mid-sized arthropod which thrived in shallow water. Like most arthropods, trilobites are divided into three basic body sections; the frontal cephalon, the middle thorax, and the read pygidium. Calymene had a near triangular cephalon and possessed large, circular eyes. Its thorax and pygidium were further divided into 18-19 small segments, most of which were attached to legs and sensory bristles. These segments also had another use-they enabled the Calymene to roll itself into a ball, much like the modern day pill bug. Many paleontologists believe that by rolling itself into a ball, the Calymene could protect its soft underbelly from ocean predators, among them nautiloids and horseshoe crabs.
The first Calymene fossils were discovered in Wisconsin by naturalist Increase A. Lapham, who frequently explored the state's vast Niagara dolomite outcroppings in the 1830's. For years scientists valued these 2-4 inch trilobites as index fossils, but it was not until 1982 when University of Wisconsin geology buff Mark Shurilla waged a campaign to adopt the "trilobite" as the official state fossil. But paleontologist Klaus Westphal was leery. Instead of having the ever-common trilobite as the state fossil, he suggested the exact species Calymene celebra. A bill was introduced to the state legislature, but it was twice killed due to what some of the scientists dismissed as "dirty political tricks." However, in 1985 the third time was a charm, as the bill passed the legislature and was officially signed into law by Governor Early on April 2, 1986. It was truly the end to a long saga, but unless another Ice Age hits it will be quite a long time until the famous Wisconsin Calymene celebra fossils disappear!
FOOTNOTE: All text is taken directly from the magazine Fossil News: The Journal of Avocational Paleontology, October 2000.
© 1997 brusatte@theramp.net
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