For Immediate Release
Contact:
Carnegie Museum of Natural History
Leigh Kish (412) 622-3361
KishL@CarnegieMuseums.org

July 28, 2009

Fossil Tracks of Seven-and-a-Half-Foot Sea Scorpion-like creature
on View Now at Carnegie Museum of Natural History

Pittsburgh, Pennsylvania…Recent beaching and attacks on divers by giant squid off the coast of California prove once again that giant sea invertebrates are formidable predators. Picture the ancient geography of Pennsylvania 350 million-years ago: think Rio de Janeiro, Brazil of today, some 20 degrees latitude south of the Equator, where vast rivers flowed out from the ancestral Appalachians cutting across the land to form deltas and beaches near the shallow tropical sea. A seven and half foot long eurypterid, a distant relative of scorpions, moves from the water onto the sandy shore. It has six paired legs, two of which act as large flippers, and a large tail. Today, all that remains of this creature is a fossilized imprint of feet and tail left in its wake. This fossilized imprint, or trace fossil, is now back on view at Carnegie Museum of Natural History.

Trace fossils are not fossils of an animal’s body, but rather tracks, footprints, burrows, and other evidence of the activities of life. Carnegie Museum of Natural History’s is the largest eurypterid trackway fossil reported in the scientific literature. Eurypterids are sometimes referred to as sea scorpions because of their scorpion-like segmented body which allowed flexibility of their bodies in hunting armored fishes and other invertebrates.

"Right now scientists do not know whether the animal that makes these tracks was aquatic or terrestrial,” said Albert D. Kollar, collection manager of invertebrate paleontology at the Carnegie Museum of Natural History. Kollar and CMNH adjunct associate curator David K. Brezinski are geologists studying the environmental conditions of the rocks to determine what the climate was like during this time. Kollar continues, “This could help determine the large size of the animal that made the trackway. We know that the Carboniferous (354 to 290 million years ago) was a time when giant size was favored in other Arthropoda (insects, spiders, and crustaceans) because of the high oxygen in the terrestrial world."

The eurypterid trackway fossil was found in 1948 by former Carnegie Museum of Natural History staff member Jim Kosinski, near the Clarion River in Elk County, Pennsylvania. In 1983, the species, named Palmichnium kosinskiorum, after Kosinski, was described by British scientists Derek E. G. Briggs and W. P. Ian Rolfe. Important for study, casts have been made of this specimen and studied at other institutions, such as Yale University and Tübingen University, Germany.

When observing the eurypterid trackway, one can see the symmetrical track marks along the sides and a groove running down the center. This shallow groove was created when the animal dragged its tail while moving about in shallow waters and may suggest evidence of this animal’s adaptive evolution of an amphibious lifestyle, moving from water to land.

On view in the Benedum Hall of Geology, this fossil helps to tell the story of Western Pennsylvania during the Mississippian Period of the Paleozoic era (545 to 250 million years ago). Pennsylvania’s location during this time at the ever-changing edge of a shallow sea, in and around which eurypterids lived, accounts for a number of geological processes that have shaped today’s topography, or more commonly, the lay of the land. Benedum Hall displays information on fossil fuels (oil and gas deposits), fossils, and dioramas that depict the ancient climates and environments of Western Pennsylvania.

Carnegie Museum of Natural History, one of the four Carnegie Museums of Pittsburgh, is ranked as one of the top five natural history museums in the country. It maintains, preserves, and interprets an extraordinary collection of 21 million objects and scientific specimens used to broaden understanding of evolution, conservation, and biodiversity. More information is available by calling 412.622.3131 or from the Web site, www.CarnegieMNH.org.

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