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.
Polydesmida is the largest order of millipedes, with more than 5,000 species, including all the millipedes reported to produce hydrogen cyanide (HCN). This order is also the most diverse of the millipede orders in terms of morphology. Millipedes in this order are found in all regions of the world other than Antarctica.
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. These features have inspired the common names bristly millipedes or pincushion millipedes. This order includes about 148 species in four families worldwide, which represent the only living members of the subclass Penicillata.
Pentazonia is a taxonomic infraclass of millipedes containing the pill-millipedes (Oniscomorpha) which can roll into a ball and the order Glomeridesmida which cannot. Defining traits (apomorphies) include divided sternites, a labrum with single median tooth, and an enlarged pygidium on the hind-most body segment. Pentazonia is in the dominant millipede subclass Chilognatha which have a calcified exoskeleton and modified sperm-transferring legs in males. In contrast to the Helminthomorpha – the other Chilognathan infraclass, the sperm-transferring legs are located on posterior body segments and known as telopods. Pentazonians are relatively short-bodied, with between 13 and 21 body segments. The Pentazonia contains one extinct order, Amynilyspedida, often referred to the Oniscomorpha.
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.
Glomeridesmidae is a millipede family of the order Glomeridesmida. This family includes two genera: The genus Glomeridesmus includes most species in this family; the genus Glomeridesmoides includes one species.
Metopidiotrichidae is a family of millipedes in the order Chordeumatida. These millipedes range from 4 mm to 17 mm in length. Adult millipedes in this family have 32 segments, not the 30 segments usually found in this order. Adult males in this family often feature a reduced or vestigial leg pair 10 as part of the gonopod complex, in addition to the two leg pairs typically modified into gonopods in this order. There are about 9 genera and at least 70 described species in Metopidiotrichidae.
Chordeumatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 7 mm to 18 mm in length and are found in Europe. Adult millipedes in this family have either 28 or 30 segments. This family features distinctive sex-linked modifications to the legs in adults: In the adult female, a legless sternite replaces the third pair of legs, and in the adult male, five pairs of legs are modified in the gonopod complex. These modifications are more extensive than those found in other adult males in this order, which often have only two leg pairs modified into gonopods. With the more extensive modifications to the legs in this family, species with the usual 30 segments feature adult females with only 49 leg pairs and adult males with only 45 pairs of walking legs, and species with only 28 segments feature adult females with only 45 leg pairs and adult males with only 41 pairs of walking legs.
Chamaesomatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 3.3 mm to 12 mm in length and are found in Europe and North Africa. Adult millipedes in this family have 26, 28, or 30 segments. This family includes the species Chamaesoma broelemanni, notable as one of only a few chordeumatidan species with only 26 segments in adults, four fewer segments than typically found in adults in this order. The adult female of this species has only 42 pairs of legs, and the adult male has only 40 pairs of walking legs, excluding two pairs of gonopods.
Hoffmaneumatidae is a family of millipedes belonging to the order Chordeumatida. This family includes two genera, one (Hoffmaneuma) found in the Russian Far East and the other (Japanoparvus) found in Japan. Millipedes in this family range from 4 mm to 6 mm in length. Adult millipedes in this family have only 28 segments, not the 30 segments usually found in this order. Adult males in this family feature a reduced leg pair 10 in addition to the two pairs normally modified into gonopods in this order. In the adult male of the species Hoffmaneuma exiguum, for example, the gonopod complex derives from all three leg pairs rather than from just the usual two.
Kashmireumatidae is a small family of millipedes belonging to the order Chordeumatida. These millipedes range from 5mm to 14mm in length and are found in East Asia. Adult millipedes in this family have only 26 or 28 segments rather than the 30 segments usually found in this order. In the species Vieteuma topali, adults have 26 segments, whereas in all other species in this family, adults have 28 segments.
Opisthocheiridae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 5 mm to 16 mm in length and are found from Belgium to Morocco. Adult millipedes in this family have 26 or 30 segments. This family includes the cave-dwelling species Opisthocheiron canayerensis, notable as one of only a few chordeumatidan species with only 26 segments in adults, four fewer segments than typically found in adults in this order. The adult female of this species has only 42 pairs of legs, and the adult male has only 40 pairs of walking legs, excluding two pairs of gonopods.
Glomeridellidae is a family of millipedes belonging to the order Glomerida. The adult males in this family have two pairs of telopods rather than the single pair found in other families in this order.
Termitodesmidae is a family of millipedes belonging to the order Glomeridesmida. These millipedes are found in India, Sri Lanka, and Vietnam. The five known species in this family are notable in that they are found only in termite mounds. Termitodesmidae is the only myriapod family known to depend on insects in such a commensal relationship.
Opisthocheiron is a genus of millipedes in the family Opisthocheiridae. These millipedes are found in France and Spain. The French entomologist Henri Ribaut created this genus in 1913 to contain the newly discovered type species Opisthocheiron penicillatum. This genus also includes the cave-dwelling species Opisthocheiron canayerensis, notable as one of only a few species in the order Chordeumatida with only 26 segments in adults, four fewer segments than typically found in adults in this order. The adult female of this species has only 42 pairs of legs, and the adult male has only 40 pairs of walking legs, excluding two pairs of gonopods.
Chamaesoma is a monotypic genus of millipede in the family Chamaesomatidae, and Chamaesoma broelemanni is the only species in this genus. This millipede is notable as one of only a few species in the order Chordeumatida with only 26 segments in adults, four fewer segments than typically found in adults this order. This species lives on the surface of the soil and is distributed across most of France and Luxembourg. The genus Chamaesoma and its only species were first described by the German zoologist Karl W. Verhoeff in 1913 based on type material found by the French zoologists Henri Brölemann and Henri Ribaut under wet leaf litter near St. Béat in the Pyrenees in France.
Lipseuma is a genus of millipedes in the family Kashmireumatidae. This genus contains only two species, the type species L. josianae and its close relative L. bernardi. Both species are troglobites found in caves in China.
Tianella is a genus of millipedes in the family Entomobielziidae. This genus includes eleven species found in Nepal, one species found in Kazakhstan, and one species found in Kyrgyzstan. This genus is notable for including the only species in the order Chordeumatida with 29 segments in adults. Most species in this genus have 29 segments in adults rather than the 30 segments usually observed in this order.
Metamastigophorophyllon is a genus of millipedes in the family Anthroleucosomatidae. This genus includes millipedes found in Azerbaijan, Iran, Russia, and Georgia. All five species in this genus have 31 segments in adults. This genus is notable for including the only species in the order Chordeumatida with 31 segments rather than the 30 segments usually observed in adults in this order.
Neocambrisoma is a genus of millipedes in the family Metopidiotrichidae. Millipedes in this genus are found in Tasmania and New South Wales in Australia. Like other genera in this family, this genus features 32 segments in adults of both sexes, rather than the 30 segments usually observed in adults in the order Chordeumatida. Accordingly, female adults in this genus have 54 pairs of legs, which is not only the maximum number observed in this order but also the maximum number fixed by species in the class Diplopoda.
