Fossils from a quarry in a region of central Wisconsin known as Blackberry Hill show that the first footprints on land were made by an extinct arthropod known as a euthycarcinoid, and this occurred in the Cambrian period, roughly 500 million years ago. The authors of the study, Joseph Collette of the University of California – Riverside, Kenneth Gass, a researcher from Wisconsin, and James Hagadorn of the Denver Museum of Nature and Science, published their findings in the May 2012 issue of the Journal of Paleontology.
The suggestion that extinct arthropods had been walking about on land in what is now called Cambrian times is not a new one. Sir Richard Owen had published that idea in 1852, based on fossil footprints that he named Protichnites from Cambrian beach sandstone of Quebec.
Photo: Joseph Collette
Paleontologists have long thought of the coelacanth as a stodgy old slowpoke: Two modern-day species of the fish—considered living fossils because of their remarkable similarity to ancient coelacanths—typically swim in a slow, almost dawdling manner. As a group, coelacanths had apparently kept the same basic body plan for hundreds of millions of years. But now, researchers have found fossils of a sleeker coelacanth—one that likely was a speedy, shark-like predator in the ancient seas west of the supercontinent Pangaea about 240 million years ago.






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