Pauropoda is a class of small, pale, millipede-like arthropods in the subphylum Myriapoda. More than 900 species in twelve families are found worldwide, living in soil and leaf mold. Pauropods look like centipedes or millipedes and may be a sister group of the latter, but a close relationship with Symphyla has also been posited. The name Pauropoda derives from the Greek pauros and pous or podus, because most species in this class have only nine pairs of legs as adults, a smaller number than those found among adults in any other class of myriapods.
Symphylans, also known as garden centipedes or pseudocentipedes, are soil-dwelling arthropods of the class Symphyla in the subphylum Myriapoda. Symphylans resemble centipedes, but are very small, non-venomous, and only distantly related to both centipedes and millipedes. More than 200 species are known worldwide.
Myriapods are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial.
Pauropodidae is the most diverse family of pauropods, containing 27 genera and more than 800 species, as well as the only known fossil pauropod, Eopauropus. This family has a subcosmopolitan distribution. Pauropods in this family are generally whitish and feature a sternal antennal branch with one seta and one globulus, setae on the head and tergites that are usually tapering or cylindrical, and a single anal plate. Like most adult pauropods in the order Tetramerocerata, most adults in this family have 9 pairs of legs, but adults in one genus, Cauvetauropus, have only 8 pairs of legs, and female adults in another genus, Decapauropus, have either 9 or 10 pairs of legs. The first species found to include pauropods with more than 9 pairs of legs was D. cuenoti, first described with 10 pairs in 1931.
Glomerida is an order of pill-millipedes found primarily in the Northern Hemisphere. Also known as northern pill millipedes, they superficially resemble pill-bugs or woodlice, and can enroll into a protective ball. They have twelve body segments, 17 to 19 pairs of legs, and males have enlarged rear legs involved in mating. The order includes about 30 genera and at least 280 species, including Glomeris marginata, the common European pill-millipede. The order contains members in Europe, South-east Asia and the Americas from California to Guatemala. Although historically considered closely related with the similar sphaerotheriidans that also enroll, some DNA evidence suggest they may be more closely related to glomeridesmidans, a poorly known order that does not enroll.
Cancer productus, one of several species known as red rock crabs, is a crab of the genus Cancer found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest.
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.
Oregonia gracilis, commonly known as the graceful decorator crab, is a species of crab belonging to the family Oregoniidae. Like other decorator crabs it habitually attaches other organisms to its back. The sessile organisms are attached to hooked setae that act as a sort of velcro attachment. This decoration provides visual and chemical camouflage thus reducing predation risk. Pacific halibut are a major predator of O. gracilis. Other predators include octopus and sea otters. The main food source of O. gracilis is floating kelp and algae that they capture utilizing a waiting strategy in order to maintain cryptosis.
Polyxenida is an order of millipedes readily distinguished by a unique body plan consisting of a soft, non-calcified body ornamented with tufts of bristles – traits that have inspired the common names "bristly millipedes" or "pincushion millipedes". There are at least 86 species in four families worldwide, and are the only living members of the subclass Penicillata.
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.
Ammodesmidae is a family of small millipedes endemic to Africa, containing seven species in two genera. Ammodesmids range from 1.4 to 5.0 mm long with 18 or 19 body segments in both sexes, and are capable of rolling into a tight sphere.
Millotauropus is a genus of pauropods in the monotypic family Millotauropodidae in the monotypic order Hexamerocerata. The order Hexamerocerata includes only eight species and was created in 1950 to contain the newly discovered genus Millotauropus, which was found to have so many distinctive features as to warrant placement in a separate order. Before the discovery of Millotauropus, for example, pauropods were thought to have no more than ten leg pairs, but adults in the order Hexamerocerata have eleven pairs of legs.
Tetramerocerata is an order of pauropods containing 11 families and more than 900 species. This order was created in 1950 to distinguish these pauropods from those in the newly discovered genus Millotauropus, which was found to have such distinctive features as to warrant placement in a separate order (Hexamerocerata) created to contain that genus. The order Tetramerocerata includes the vast majority of pauropod species, as there are only eight species in the order Hexamerocerata, which remains the only other order in the class Pauropoda.
Brachypauropodidae is a family of pauropods. Pauropods in this family feature an entire first tergite, but at least the next three tergites are each divided into four to six sclerites, and the pygidial sternum has two or three pairs of setae. Like most adult pauropods in the order Tetramerocerata, most adults in this family have 9 pairs of legs, but adults in a few species in two genera, Aletopauropus and Zygopauropus, have only 8 pairs of legs. This family has a nearly worldwide distribution and is found on all continents except South America and Antarctica.
Linotaeniidae are a monophyletic clade of soil centipedes in the family Geophilidae found mostly in the temperate regions of the Holarctic as well as the south Andes. Species in the clade Linotaeniidae are characterized by a body that usually tapers toward the anterior tip; mandibles with a single pectinate lamella; second maxillae with coxo-sternite usually undivided and claws without projections; forcipular segment short, with tergite remarkably wide, forcipules evidently tapering; coxal organs opening through distinct pores on the ventral surface of the coxo-pleura. The number of legs in this clade varies within as well as among species and ranges from as few as 31 pairs of legs to as many as 83 leg pairs. Compared to most families in the suborder Adesmata, this clade features a modest number of leg-bearing segments and limited variation in this number within each species.
Schendylidae is a family of centipedes in the order Geophilomorpha found in the Americas, the Palearctic region, Africa, Madagascar, Australia, and southeast Asia, and also on some Pacific islands.
Scolopendrellidae is a family of symphylans in the class Symphyla. There are about 9 genera and at least 100 described species in Scolopendrellidae.
Brachydesmus is a genus of millipedes belonging to the family Polydesmidae. Millipedes in this genus are found mainly in Europe. Species in this genus have only 19 segments as adults, one fewer than found in most polydesmid species. Accordingly, adults in this genus have two fewer pairs of legs than most polydesmid adults have: Females have only 29 pairs of legs, and males have only 28 pairs of walking legs, excluding one pair of gonopods. Species in this genus arrive at these lower numbers of legs and segments by going through the same stages of teloanamorphosis observed in other polydesmids but reaching maturity one moult earlier.
Ribautia is a genus of centipedes in the family Geophilidae. This genus was described by French myriapodologist Henry Wilfred Brolemann in 1909. Centipedes in this genus are found in South America, tropical Africa, Madagascar, the Arabian peninsula, Australia, New Zealand, and Melanesia.
Zygopauropus is a monotypic genus of pauropod in the family Brachypauropodidae. The only species in this genus is Zygopauropus hesperius, first described by J.W. MacSwain and U.N. Lanham of the University of California at Berkeley in 1948. This genus is notable as one of only four genera of pauropods in which adults have only eight pairs of legs rather than the nine leg pairs usually found in adults in the order Tetramerocerata. Before the discovery of Z. hesperius, adult pauropods were thought to have only nine or (rarely) ten pairs of legs.
