Tags: Arachnid.
Arthrolycosa (meaning wolf [spider] with joints) is an extinct genus of spiders that lived about 300-250 million years ago. Fossils have been found Mazon Creek USA and in the Kirov Oblast region of Russia which consisted of a single carapace. The carapace is about as wide as it is long.Arthrolycosa is estimated to have grown to a length of 2 inches (5 centimeters) and may have preyed upon insects and other smaller animals that lived alongside it.