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.
Should "show that the first footprints on land were made by an extinct arthropod...euthycarcinoid" read "show that the earliest known footprints on land were made by an extinct arthropod...euthycarcinoid"?
Apparently not. The article seems to suggest that whatever type of life may have first put footprints upon the earth, the certitude is very high that it wasn't a fish or amphibian.
What drove them to land? Best guess so far: Sex.
Photo: Joseph Collette