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Myriapoda: Myriapods are any invertebrate belonging to the subphylum Myriapoda. This subphylum contains 4 classes, with the two most well-known being Chilopoda (centipedes) and Diplopoda (millipedes). Myriapods have one pair of antennae and mandibles like insects do; however, unlike insects, Myriapods do not have compound eyes. Myriapods can be easily recognized by their unique tagmosis. All Myriapods have a head and a multi-segmented trunk, with multiple legs running down either side of their body. Centipedes: Class Chilopoda Centipedes are easily distinguishable from millipedes by only having one pair of legs per body segment on their trunk. They are primarily nocturnal predators, utilizing their first pair of legs which have been modified into claws with attached venom glands. Many centipedes found here in the southwestern U.S. have a “pseudo-head.” Their tail end has a pair of enlarged, sensory hind legs which do not assist in locomotion; however, they do look similar to the centipede’s true head. This is likely used to confuse potential predators into attacking the wrong end of the centipede. 
NPS Photo James C Akers Order Scolopendromorpha Common Desert/Tiger Centipede Scolopendra polymorpha The common desert centipede has extremely varied coloration; hence the species name polymorpha, which means “many forms”. Despite the many variations in coloration, the common desert centipede always has one dark, lateral stripe on each body segment. This is where it’s other common name, the tiger centipede, comes from. Like most Chilopods, this centipede is a nocturnal predator and avoids the desert heat by hiding under rocks or in moist environments during the day. 
NPS Photo Alex Klug Scolopendra heros This is the largest species of centipede found in the U.S., growing up to 8 inches in the wild and even longer in captivity. This centipede exhibits aposematism, or warning coloration, to warn potential predators of its venom. Like S. polymorpha, the giant redheaded centipedes have a few different color variations, though most found in Texas will have a brightly colored head and darker trunk (S. heros var. castaneiceps). To more accurately distinguish S. heros from S. polymorpha, look at the terminal legs. The terminal legs will be shorter and thicker on the common desert centipede. 
NPS Photo James C Akers Order Scutigeromorpha These centipedes can be quite intimidating with their long legs and quick movements. They only have 15 pairs of legs, which is much less than their cousins! Additionally, they also are the only order of centipedes that have two compound eyes, which they use to assist them in hunting. There is a common, introduced species that is often found in houses, though we have a native genus that lives here in Texas, too! 
NPS Photo James C Akers Order Geophilomorpha Soil centipedes in this order behave similarly to earthworms. They live in the soil, moving about by expanding and contracting their body, where they feed on insect larvae and worms found within. They can be identified by their slow movement, lack of eyes, and having 14 segmented antennae. They also tend to have a more gracile build compared to their other relatives.
Stone Centipedes Order Lithobiomorpha Stone centipedes are commonly found in the upper layers of soil, primarily under rocks or fallen logs. Like most centipedes, this order is either blind or only has simple eyes (ocelli). They can be easily identified compared to other centipedes by their unique body segment (tergite) length pattern. In stone centipedes, tergites 1, 3, 5, 7, 8, 10, 12, and 14 are longer than the others. They also only reach 15 pairs of legs at maturity.
Millipedes: Class Diplopoda Millipedes are the gentler, distant cousins of centipedes. They lack the modified prehensor front legs and venom glands, instead they are primarily detritivores. Millipedes can be distinguished from centipedes further by having two pairs of legs on each segment (though each segment is technically two segments fused together during the embryonic development stage). Compared to centipedes, millipedes are also more cylindrical, and the legs extend vertically straight down, making them harder to view from the sides. 
NPS Photo James C Akers Orthoporus ornatus Like most millipedes, the desert millipede is a slow moving detritivore. They are nocturnal, though they will often appear early morning if it rained the previous day. Desert millipedes are typically brown or black with a cylindrical body and can live up to 10+ years old. On rare occasions they have been known to form large groups and “march” across roads at our sister park, Big Bend. 
NPS Photo Alex Klug Comanchelus chihuanus Little is known about this millipede. It is quite rare, with few known ranges in the southwestern U.S. Like other millipedes, it avoids desiccation by burrowing underground and feeding on decaying organic matter found in the soil. Occasionally they will emerge after heavy rains when there is sufficient moisture in the air. |
Last updated: February 6, 2019