More than 300 million years ago, all sorts of arachnids crawled around in the Carboniferous coal forests. There were also some quite strange-looking arachnids which belonged to groups that are now long extinct. One such fossil was described in a new paper published in Journal of Paleontology, co-authored by Paul Selden from the University of Kansas and Jason Dunlop from the Museum für Naturkunde Berlin. Douglassarachne acanthopoda comes from the Mazon Creek locality in Illinois, USA, and is 308 million years old. This compact arachnid is characterized by its remarkably robust and spiny legs, such that it is quite unlike any other arachnid known: living or extinct.