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 ball. Although the name "millipede" derives from the Latin for "thousand feet", no known species has 1,000; the record of 750 legs belongs to Illacme plenipes. 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.
Centipedes are predatory arthropods belonging to the class Chilopoda of the subphylum Myriapoda, an arthropod group which also includes millipedes and other multi-legged creatures. Centipedes are elongated metameric creatures with one pair of legs per body segment. Most centipedes are venomous and can inflict painful bites, injecting their venom through pincer-like appendages known as forcipules. Despite the name, centipedes can have a varying number of legs, ranging from 30 to 354. Centipedes always have an odd number of pairs of legs. Therefore, no centipede has exactly 100 legs. Like spiders and scorpions, centipedes are predominantly carnivorous.
Hibbertopterus is a genus of eurypterid, a group of extinct aquatic arthropods. Fossils of Hibbertopterus have been discovered in deposits ranging from the Devonian period in Belgium, Scotland and the United States to the Carboniferous period in Scotland, Ireland, the Czech Republic and South Africa. The type species, H. scouleri, was first named as a species of the significantly different Eurypterus by Samuel Hibbert in 1836. The generic name Hibbertopterus, coined more than a century later, combines his name and the Greek word πτερόν (pteron) meaning "wing".
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.
Mammamia profuga is a species of cave-dwelling millipede in the family Julidae. The only known species of the genus Mammamia, it was described in 2011 from a specimen discovered in a cave in Italy.
Polydesmida is the largest order of millipedes, containing approximately 3,500 species, including all the millipedes reported to produce hydrogen cyanide (HCN).
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.
Julida is an order of millipedes. Members are mostly small and cylindrical, typically ranging from 10–120 millimetres (0.39–4.72 in) in length. Eyes may be present or absent, and in mature males of many species, the first pair of legs is modified into hook-like structures. Additionally, both pairs of legs on the 7th body segment of males are modified into gonopods.
Trogloraptor is a genus of large spiders found in the caves of southwestern Oregon. It is the sole genus in the family Trogloraptoridae, and includes only one species, Trogloraptor marchingtoni. These spiders are predominantly yellow-brown in color with a maximum leg span of 3 in (7.6 cm). They are remarkable for having hook-like claws on the raptorial last segments of their legs.
Callipodida is an order of millipedes containing around 130 species, many characterized by crests or ridges.
Sinocallipus is a genus of predominantly cave-dwelling millipedes in the order Callipodida. Five of the six known species are found in limestone caves on the Indochinese Peninsula from Vietnam to southern China, and it is the only callipodidan genus entirely confined to the tropics. Individuals range from 40–70 mm (1.6–2.8 in) long and possess 55 to 70 segments. Sinocallipus is the sole taxon of the callipodidan suborder Sinocallipodidea, and thought to be the most primitive and sister group to all other callipodidans. In contrast to many other millipede groups, the gonopods of Sinocallipus show little variation between species, while other characters such as color, size, and other body parts differ more noticeably between species.
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.
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.
Aprosphylosoma darceneae is a species of cylindrical julidan millipede found only in the U.S. state of Oregon and comprising the sole species of the family Aprosphylosomatidae. It is known from only a single known specimen collected from Oregon Caves National Monument in 1956 that measures approximately 16 mm (0.63 in) long and 1 mm wide, possessing 59 body segments. The first pair of legs are extremely reduced into non-jointed, peg-like structures. The body color is yellowish brown with darker brown mottling on the dorsal surface, and the legs are white.
Paeromopus is a genus of large cylindrical millipedes endemic to the U.S. state of California. All species exceed 10 centimeters in length, and the largest, P. paniculus, reaching 16.5 cm is the longest millipede species in North America. The genus was named by German entomologist Ferdinand Karsch in 1881 and contains four species: three occupying small ranges in the Sierra Nevada mountains and one occupying a large range including the Sierra Nevada and much of Northern California to the Central Coast.
Paeromopus paniculus is a species of millipede endemic to the Sierra Nevada mountains in the United States state of California. Reaching up to 16.5 centimeters in length, it is the longest known millipede in North America.
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.
Juliformia is a taxonomic superorder of millipedes containing three living orders: Julida, Spirobolida, and Spirostreptida, and the extinct group Xyloiuloidea known only from fossils. The species possess long cylindrical bodies with sclerites fused into complete rings. Juliform millipedes possess defensive repugnatorial glands on all body segments except the last few, and are the only known millipedes to produce quinones in their defensive secretions. Juliform males have two pairs of gonopods consisting of the modified 8th and 9th pair of legs: in Julida and Spirobolida the posterior gonopods are primarily involved in sperm-transferring, while in Spirostreptida it is the anterior gonopods. Juliformians also lack Tömösváry organs and have a large collum which overhangs the rear of the head.
Boreohesperus is a genus of paradoxosomatid millipedes containing six species native to Western Australia. The name refers to the northwestern distribution in Australia, deriving from Boreas, Greek god of the North, and hesperus, Latin for "west".
Necrogammarus salweyi is the binomial name applied to an arthropod fossil discovered in Herefordshire, England. The fossil represents a fragmentary section of the underside and an appendage of a pterygotid eurypterid, a group of large and predatory aquatic arthropods that lived from the late Silurian to the late Devonian. The Necrogammarus fossil is Late Silurian in age and its generic name means "dead lobster", deriving from Ancient Greek νεκρός and Latin gammarus ("lobster").
