Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a result of two single segments fused together. Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a tight ball. Although the name "millipede" derives from Latin for "thousand feet", no species was known to have 1,000 or more until the discovery in 2020 of Eumillipes persephone, which can have over 1,300 legs. There are approximately 12,000 named species classified into 16 orders and around 140 families, making Diplopoda the largest class of myriapods, an arthropod group which also includes centipedes and other multi-legged creatures.
Narceus americanus is a large millipede of eastern North America. Common names include American giant millipede, worm millipede, and iron worm. It inhabits the eastern seaboard of North America west to Georgetown, Texas, north of the Ottine wetlands. It has a nearly cylindrical gray body, reaching a length of 4 inches (100 mm). They can be commonly found in or under decaying logs from March to October. When threatened, they sometimes curl up or release a noxious liquid that contains large amounts of benzoquinones which can cause dermatological burns. This fluid may irritate eyes or skin. Many other millipedes secrete hydrogen cyanide, and while there have also been claims that N. americanus releases hydrogen cyanide, they are unsubstantiated. They do, however, excrete a substance that causes a temporary, non-harmful discoloration of the skin known as millipede burn.
Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipedes, gonopods are modified walking or swimming legs. Gonopods may be highly decorated with elaborate structures which may play roles in sperm competition, and can be used to differentiate and identify closely related species. Gonopods generally occur in one or more pairs, as opposed to the single (un-paired) reproductive organs such as the aedeagus of insects or the penis of harvestmen.
Harpaphe haydeniana, commonly known as the yellow-spotted millipede, almond-scented millipede or cyanide millipede, is a species of polydesmidan ("flat-backed") millipede found in the moist forests along the Pacific coast of North America, from Southeast Alaska to California. The dark coloration with contrasting yellow-tipped keels warn of its ability to exude toxic hydrogen cyanide as a defense. The cyanide secretions are not dangerous to humans, but can cause irritation and pain if it contacts sensitive areas such as the mouth, eyes, or nose.
Trichopetalum whitei, common name Luray Caverns blind cave millipede, is a rare troglobitic millipede of the upper Potomac River drainage in four Virginia counties and three West Virginia counties. It has been recorded from 12 caves across this range, including the Luray Caverns where it was first discovered and described.
Desmoxytes, whose species are commonly known as the dragon millipedes, is a genus of millipedes of the family Paradoxosomatidae found in Southeast Asia. The genus was described by Ralph Vary Chamberlin in 1923, and reviewed by Sergei Golovatch and Henrik Enghoff in 1994. At least 18 species are known from to Malaysia, Myanmar, and Thailand. One species, D. planata, has also been observed in Sri Lanka, the Andaman Islands, Seychelles, Java, Great Coco Island, and Fiji; however, this species has expanded its range by being transported through human activity. Several species have only recently been discovered, and some have yet to be officially described.
Desmoxytoides hasenpuschorum is a species of millipede and the only species in the monotypic genus Desmoxytoides. It lives in Australia. This species is closely related to the dragon millipedes of the genus Desmoxytes, and there is some speculation, even by Robert Mesibov, the genus authority, that the split may not be necessary. While Desmoxytoides hasenpuschorum is similar to the millipedes of Desmoxytes in paranotal form and metatergite sculpture, it has a simpler gonopod telopodite with an unprotected solenomere which gives it its own monotypic genus. This species has the ability to produce hydrogen cyanide to ward off predators.
Polydesmida is the largest order of millipedes, containing approximately 3,500 species, including all the millipedes reported to produce hydrogen cyanide (HCN). Polydesmids grow and develop through a series of moults, adding segments until they reach a fixed number in the adult stage, which is usually the same for a given sex in a given species, at which point the moulting and the addition of segments and legs stop. This mode of development, known as teloanamorphosis, distinguishes this order from most other orders of millipedes, which usually continue to moult as adults, developing through either euanamorphosis or hemianamorphosis.
Ommatoiulus moreleti, commonly known as the Portuguese millipede, is a herbivorous millipede native to the western Iberian Peninsula where it shares its range with other Ommatoiulus species. From here, it has spread by international commerce to a number of new localities. This species was accidentally introduced into Australia without its natural enemies and has since become an invasive pest. A number of methods have been developed to manage this millipede.
Xystodesmidae is a family of millipedes. Its members often have very small distributional areas, with many species only known from a single locality. They are found across the northern hemisphere, with peak diversity in the Appalachian Mountains, where one-third of the 300 or so species occur. They are particularly abundant in deciduous broadleaf forests in the Mediterranean Basin, Africa, Asia, Central and North America, and Russia. Information on basic taxonomy is scant for this family; for example, it is estimated that the genus Nannaria contains over 200 species, but only 25 were described as of 2006. By 2022, 78 species in Nannaria have been described.
Paradoxosomatidae, the only family in the suborder Paradoxosomatidea, is a family of flat-backed millipedes in the order Polydesmida. Containing nearly 200 genera and 975 species as of 2013, it is one of the largest families of millipedes. Paradoxosomatids occur on all continents except Antarctica, and can generally be distinguished by dorsal grooves on most body segments and a dumb-bell shaped gonopod aperture. Notable groups within the Paradoxosomatidae include the dragon millipedes of Southeast Asia, and the widely introduced greenhouse millipede Oxidus gracilis.
Motyxia is a genus of cyanide-producing millipedes that are endemic to the southern Sierra Nevada, Tehachapi, and Santa Monica mountain ranges of California. Motyxias are blind and produce the poison cyanide, like all members of the Polydesmida. All species have the ability to glow brightly: some of the few known instances of bioluminescence in millipedes.
Orthoporus ornatus is a North American species of millipede in the family Spirostreptidae that can be found in the U.S. states of Arizona, New Mexico and Texas, and as far south as the Mexican state of San Luis Potosí. They became very popular in the pet trade and many were exported to Western Europe. Brian Van Der Kieft and Max Prins were the first breeders of this species in Europe. Individuals on average are 4 inches (10 cm) in length, but can either be as small as 3 inches (76 mm), or exceed up to 9 inches (230 mm) in length. They are dark brownish coloured, but can sometimes be yellow. In fact, in every state the species look different. The antennae are located near the organs of Tömösváry. The species feed on both living and dead organic material. The species prefer sunshine, but can be seen on summer rainy days as well. A disturbed Orthoporus ornatus may curl into a coil and release a toxic substance that is located on all sides of its body. The species can live more than ten years. The species feed on shrubs of Ephedra, which grows in Jornada del Muerto, and on Salsola that grows in Albuquerque.
Chordeumatida is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as sausage millipedes, they grow and develop through a series of moults, adding segments until they reach a fixed number in the adult stage, which is usually the same for a given sex in a given species, at which point the moulting and the addition of segments and legs stop. This mode of development, known as teloanamorphosis, distinguishes this order from most other orders of millipedes, which usually continue to moult as adults, developing through either euanamorphosis or hemianamorphosis.
Siphoniulus is a poorly known genus of millipede containing only two living species: S. alba from Indonesia, and S. neotropicus from Mexico and Guatemala. An additional two fossil species are known from Cretaceous amber. Siphoniulus species are the only members of the family Siphoniulidae and order Siphoniulida, making Siphoniulida the smallest millipede order. Few specimens are known, and their classification is contentious, although most recent studies place them as basal members of the Helminthomorpha.
Orthomorpha coarctata, the long-flange millipede, is a widely introduced species of Polydesmidan millipede of the family Paradoxosomatidae. It is presumed native to Southeast Asia but due to transport by humans occurs in tropical and sub-tropical areas throughout the world, including the Hawaiian Islands, the West Indies, Gulf Coast of North America, and the Galápagos Islands.
Floridobolus is a genus of millipedes commonly known as Florida scrub millipedes containing three described species: Floridobolus penneri, F. orini, and F. floydi; the latter two described in 2014. All three species are endemic to Florida scrub habitat of peninsular Florida, and F. penneri is considered a critically imperiled species by NatureServe. Prior to the description of F. orini, the genus was considered the sole member of the family Floridobolidae, named by William T. Keeton in 1959, however studies in 2014 have argued that Floridobolus does not represent a distinct family but rather is a basal member of the family Spirobolidae, representing the subfamily Floridobolinae, and tribe Floridobolini.
Brachycybe (Greek for "short head") is a genus of andrognathid millipedes with species in the United States and East Asia. In a rare example of paternal care in invertebrates, males of most species guard the eggs until they hatch.
The Phengodes laticollis, is a species of the Glowworm Beetle within the family of Phengodidae. The name Phengodidae is the scientific name for a beetle in which their larvae are glowworms and are thus named for their bioluminescent qualities.
Oxidus is a genus of flat-backed millipedes in the family Paradoxosomatidae. There are about nine described species in Oxidus.
