The Silurian Millipedes are apparently the ancestors of the Arthropleura, seen in the later Carboniferous Period. They roam in groups across the sand and are prey to the much larger Giant Scorpions of the era. They prefer to hide in the sand but may emerge if they are frightened by a predator. The destructive capabilities of these animals are unknown; it is unknown if they carry venom. Eoarthropleura may scavenge detritus, or they may eat some of the primitive land plants that exist in the Silurian.
When Nick and Stephen went through an anomaly to the Silurian, they saw dozens of Eoarthropleura running from something, but could not see what. Later one entered the present through the anomaly and Connor and Abby chased it until it reached a ball pool in a restaurant. Abby eventually caught the hiding creature and released it back into the Silurian before the anomaly closed.