Appearing in the Jurassic Period, Eryma represents the oldest known 'true' lobster. Eryma is characterized by having typical decapod-like features, which include multiple pairs of appendages, such as antennae and mouth parts, as well as the ten main limbs. In addition, it had an elongated, segmented body, tough exoskeleton armour (carapace) that covers the thorax and head, and a fan-like tail, or telson.