What are the Major Groups of Myriapods?
Myriapods are members of Myriapoda, a subphylum of arthropods. They include the familiar millipedes and centipedes as well as the very small and rarely seen symphylans and pauropodans. Myriapods are the first known land animals, with one fossil of a millipede dating back to the late Silurian, 428 million years ago. It is known to have been terrestrial because of the presence of small breathing holes called spiracles. There is the possibility that myriapods are even older, as molecular evidence indicates a major diversification episode in an even older era, the Cambrian, and there are some Cambrian fossils that may be myriapods. The most familiar and largest myriapods are the millipedes and centipedes, many-legged arthropods whose number of legs ranges from under ten to 750, depending on species. Both live in decaying plant material, though millipedes actually eat the leaf litter while centipedes prowl it for prey such as small insects. Millipedes and centipedes look strikingly differen
