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.
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.
Richard Lawrence Hoffman was an American zoologist known as an international expert on millipedes, and a leading authority on the natural history of Virginia and the Appalachian Mountains. He was a biology professor at Virginia's Radford College for almost thirty years, and curator of invertebrates at the Virginia Museum of Natural History for another twenty years. He co-founded the Virginia Natural History Society, described over 400 species of millipedes, and produced more than 480 scientific publications. He is commemorated in the scientific and/or common names of over 30 animal species, including the valley and ridge salamander and Hoffman's dwarf centipede.
Brachoria is a genus of polydesmidan millipedes in the family Xystodesmidae inhabiting the Eastern United States. Also known as the Appalachian mimic millipedes, at least 30 species are known, with highest diversity in the Appalachian Mountains, especially the Cumberland Plateau and Ridge and Valley Province.
Parafontaria is a genus of "flat-backed" millipedes consisting of 14 species native to Japan and Korea. Parafontaria laminata armigera, formerly called train millipedes, has been synonymized with P. laminata. This is because some populations exhibit periodical swarming behavior during which large numbers congregate and can impact train passage when this congregation occurs on tracks. Documentation of this event goes back to 1920. Individuals vary from around 3.5 to 6 cm as adults, and feed on leaf litter as well as soil, making them comparable to earthworms in facilitating decomposition and soil nutrient cycling.
Apheloria tigana, known as the yellow-and-black flat millipede, is a large North American flat-backed millipede in the family Xystodesmidae. It is reported to secrete cyanide compounds as a defense. It is recommended that one wash hands after handling this organism as the toxic compounds it secretes are poisonous and can cause extreme irritation if rubbed in the eyes.
Brachoria dentata, the Pennington Gap mimic millipede, is an Appalachian mimic millipede in the Xystodesmidae family.
Pseudopolydesmus is a genus of flat-backed millipedes in the family Polydesmidae.
Pleuroloma flavipes, commonly known as the traveling cherry millipede, is a species of flat-backed millipede in the family Xystodesmidae. It has the widest distribution of any species of xystodesmid millipede and is found in eastern North America from southeastern North Dakota, eastward to Connecticut, and southward to North Carolina, northern Louisiana, and southern Texas. Pleuroloma flavipes millipedes are occasionally observed in large aggregations of individuals where they appear to move en masse in a certain direction, hence the common name "wandering cherry millipede". In a report from 1950, an aggregation of about 6,000 individuals were encountered on a single bridge at McCormick's Creek State Park, Indiana. The species is extremely variable in coloration, and converges in appearance with several species of Apheloria and Brachoria as a result of mimicry.
Pachydesmini is a tribe of flat-backed millipedes in the family Xystodesmidae. There are at least 3 genera and more than 20 described species in Pachydesmini.
The genus Nannaria, commonly known as twisted-claw millipedes, is a genus of millipedes in the family Xystodesmidae first described by Ralph Chamberlin in 1918. In 2022, entomologists Derek Hennen, Jackson Means and Paul Marek discovered and described 17 new species, which expanded the size of Nannaria to 78, making it the largest genus of Xystodesmidae.
Chonaphini is a tribe of flat-backed millipedes in the family Xystodesmidae. There are about 6 genera and 19 described species in Chonaphini.
Apheloria montana is a species of flat-backed millipede in the family Xystodesmidae. It is found in North America.
Xystocheirini is a tribe of flat-backed millipedes in the family Xystodesmidae. There are about 5 genera and more than 40 described species in Xystocheirini.
Sigmoria is a genus of flat-backed millipedes in the family Xystodesmidae. There are more than 60 described species in Sigmoria, found in the eastern United States.
Cherokia Chamberlin, 1949 is a genus consisting of a single species, Cherokia georgiana. Commonly known as the wrinkled flat-backed millipede, this species belongs to the order Polydesmida and the family Xystodesmidae. It inhabits forests in the southeastern United States, particularly those with hemlock, maple, tulip poplar, rhododendron, cedar, and spruce-fir trees.
Rudiloria is a genus of millipedes in the family Xystodesmidae, found in eastern North America.
Rudiloria kleinpeteri is a species of millipede in the family Xystodesmidae. Its distribution range is limited to an area in Virginia and West Virginia in the United States.
Nannaria swiftae, also known as the Swift twisted-claw millipede or Taylor Swift's millipede, is a species of millipede in the family Xystodesmidae. It is found only in the Appalachian mountains of the U.S. state of Tennessee. It was discovered and described in 2022 by entomologists Derek Hennen, Jackson Means and Paul Marek, who expanded the genus Nannaria to 78 species. They named the species in honor of American singer-songwriter Taylor Swift.
Devillea is a genus of flat-backed millipedes in the family Xystodesmidae. These millipedes are rare and limited to caves. Species in this genus are found in Sardinia, Capri, and southern France in the Maritime Alps. These species are notable for featuring more than the 20 segments usually found in the order Polydesmida. This genus is one of only two genera in this order to feature these extra segments and the first such genus to be discovered.
