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.
Xystodesmidae is a family of millipedes in the suborder Leptodesmidea within the order Polydesmida. The family Xystodesmidae was created by the American biologist Orator F. Cook in 1895 and named after the genus Xystodesmus. This family includes more than 390 known species distributed among 62 genera. Many species, however, remain undescribed: 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.
Zephroniidae is a family of giant pill millipedes in the taxonomic order Sphaerotheriida. They occur in southeast Asia from the Himalayas and China south and east to Sulawesi and to Australia, and also inhabit some Philippine islands.
Polyxenidae is a family of millipedes in the order Polyxenida containing approximately 47 species in 19 genera. All adults in this family have 13 pairs of legs.
Polyzoniida is an order of millipedes in the subterclass Colobognatha. This order contains three families and more than 70 described species. The species in this order are also known as camphor millipedes, because ozopore secretions in this order frequently have a strong camphor-like smell. Poison frogs in South America and Madagascar evidently obtain some of their poison from these millipedes.
Chordeumatida is a large order of millipedes containing more than 1,400 species. Also known as sausage millipedes, they are found nearly worldwide. Chordeumatida is the largest order in the superorder Nematophora, a group also known as spinning millipedes because their telsons feature spinnerets used to build nests of silk. These millipedes produce this silk to create chambers in which to molt or to lay their eggs.
Anthroleucosomatidae is a family of millipedes in the order Chordeumatida. This family includes more than 100 species distributed among 40 genera. This family has a mostly Holarctic distribution, with the greatest diversity in the area around the Mediterranean sea.
Caseyidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 30 segments. There are about 7 genera and at least 40 described species in Caseyidae.
Conotylidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 30 segments. There are about 19 genera and at least 60 described species in Conotylidae.
Craspedosomatidae is a family of millipedes in the order Chordeumatida. Most adult millipedes in this family have 30 segments, but some have only 28. There are at least 30 genera and 210 described species in Craspedosomatidae.
Rhinotus is a genus of millipedes in the family Siphonotidae. There are at least 20 described species in Rhinotus.
Metopidiotrichidae is a family of millipedes in the order Chordeumatida. This family includes more than 70 species. These millipedes are found in Indochina, Australia, and on Pacific islands from New Zealand to Japan.
Mastigophorophyllidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 30 segments.
Brachychaeteumatidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 30 segments.
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.
Haaseidae is a family of millipedes belonging to the order Chordeumatida. This family includes 29 species. These millipedes are found in central and southeastern Europe.
Attemsiidae is a Palaearctic family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 30 segments.
Entomobielziidae is a family of millipedes belonging to the order Chordeumatida. This family includes 18 species, including 13 in the genus Tianella. Millipedes in this family are found in Romania, central Asia, and the Himalayas.
Trachygonidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 28 or 30 segments.
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.
