Millipedes are medium to large-sized invertebrates, arthropods of the class Diplopoda. They are also some of the oldest animals known to live on land, their first appearance in historical sources being traced as far back as the Silurian period. There are approximately 12,000 recognized species of millipedes (in reality, numbers are estimated to be around 15,000 – 20,000 and can go as high as 80,000), classified into 2 subclasses, 16 orders, and 140 families.
