Xystodesmidae
Guides
Apheloria montana
mountain cherry millipede
Apheloria montana is a large flat-backed millipede in the family Xystodesmidae, native to the southern Appalachian Mountains of eastern Tennessee and western North Carolina. It serves as the type species for the genus Apheloria. The species produces hydrogen cyanide and benzaldehyde as chemical defenses, which emit a characteristic cherry or almond odor. Its bright yellow or orange spots function as aposematic coloration warning predators of its toxicity.
Apheloria virginiensis reducta
Yellow-and-black millipede, Cyanide millipede
A large, colorful millipede in the family Xystodesmidae, distinguished by its black body with bright yellow or orange wedge-shaped posterolateral markings. Like other members of its genus, it produces hydrogen cyanide as a chemical defense, advertised by its conspicuous aposematic coloration. The subspecies represents a western population of A. virginiensis, with records extending from the Appalachian region through the Ozark Plateau to the Arkansas Delta.
Boraria deturkiana
Boraria deturkiana is a species of flat-backed millipede in the family Xystodesmidaedescribed by Causey in 1942. The genus Boraria is part of the tribe Rhysodesmini within the subfamily Rhysodesminae. Like other members of the order Polydesmida, this species possesses laterally expanded dorsal segments (paranota) that give it a flattened appearance. The taxonomic status of this species has been debated, with some sources treating it as a synonym of Howellaria deturkiana.
Boraria infesta
Boraria infesta is a species of flat-backed millipede in the family Xystodesmidae, native to southeastern North America. It belongs to a group of polydesmidan millipedes that produce hydrogen cyanide as a chemical defense and display aposematic coloration warning predators of their toxicity. The species is part of a genus closely related to other cyanide-producing millipedes including Apheloria and Pleuroloma.
Cherokia georgiana
Georgia Flat-backed Millipede, Wrinkled Flat-backed Millipede
Cherokia georgiana is a monospecific millipede genus in the family Xystodesmidae, representing the sole species in genus Cherokia. Molecular phylogenetic analysis of seven gene loci supports recognition of a single highly variable species, with three formerly recognized subspecies (C. g. ducilla, C. g. latassa) now synonymized. The species exhibits extensive morphological variation in coloration, body size, and paranota shape that correlates with geography and elevation rather than phylogenetic relationships. It is sister to the genus Pleuroloma.
Furcillaria
Furcillaria is a genus of flat-backed millipedes established by Shelley in 1981 within the family Xystodesmidae. It originally comprised four species from the eastern United States: Furcillaria aequalis, F. convoluta, F. laminata, and F. thrinax. In 2021, taxonomic authorities reevaluated the genus and deemed it a junior synonym of Sigmoria, a decision now reflected in major databases such as the Catalogue of Life. Some sources, including GBIF and NCBI, continue to list Furcillaria as accepted, reflecting ongoing taxonomic debate or lag in database updates. The genus belongs to the tribe Apheloriini, a group of xystodesmid millipedes characterized by complex gonopod morphology.
Gyalostethus
Gyalostethus is a genus of flat-backed millipedes in the family Xystodesmidae, described by Hoffman in 1965. It belongs to the tribe Rhysodesmini and is part of the diverse order Polydesmida, which contains many North American millipede species. The genus is poorly documented in scientific literature, with limited species-level information available.
Montaphe elrodi
Montaphe elrodi is a species of flat-backed millipede in the family Xystodesmidae, first described by Chamberlin in 1913 under the basionym Leptodesmus elrodi. It belongs to the order Polydesmida, a diverse group of millipedes characterized by their flattened body form. The species is known from North America, though specific details about its biology remain limited in published literature.
Nannaria
Twisted-Claw Millipedes
Nannaria is a genus of small-bodied millipedes in the family Xystodesmidae, commonly known as twisted-claw millipedes. First described by Ralph Chamberlin in 1918, it is now the largest genus in its family with 78 described species following major revisions in 2022. The genus comprises two monophyletic species groups: the widespread minor group found throughout eastern North America, and the wilsoni group restricted to the Appalachian Mountains. Unlike many colorful, flat-backed xystodesmids, Nannaria species are cryptic in appearance and exhibit subterranean behavior that makes them difficult to collect.
Nannaria cingulata
Swamp-Dwelling Twisted-Claw Millipede
Nannaria cingulata is a species of twisted-claw millipede in the family Xystodesmidae, described in 2021 from the Appalachian Mountains of the eastern United States. The species belongs to a genus of small, soil-dwelling millipedes that are cryptic and difficult to collect. Like other members of its genus, it plays a role as a decomposer in forest ecosystems. The specific epithet refers to a banded or girdled appearance.
Nannaria hardeni
Curt Harden's Twisted-Claw Millipede
Nannaria hardeni is a species of twisted-claw millipede described in 2021 from the Appalachian Mountains of the eastern United States. It belongs to the genus Nannaria, a group of forest-dwelling millipedes characterized by males having small, twisted and flattened claws on their anterior legs. The species was named in honor of Curt Harden, a millipede researcher who contributed significantly to the study of Appalachian xystodesmid millipedes. Like other members of its genus, N. hardeni plays a role as a decomposer in forest ecosystems.
Nannaria terricola
Loam-dwelling Twisted-Claw
Nannaria terricola is a flat-backed millipede in the family Xystodesmida, characterized by its loam-dwelling habits and the distinctive twisted, flattened claws on the anterior legs of males. The species is found in the Great Lakes region of the United States. Like other members of the genus Nannaria, it plays a role as a decomposer in forest ecosystems. The species was originally described as Fontaria terricola by Williams & Hefner in 1928 before being transferred to Nannaria.
Nannariini
Nannariini is a tribe of flat-backed millipedes within the family Xystodesmidae, subfamily Rhysodesminae. The tribe was established by Hoffman in 1964 and comprises several genera of small to medium-sized polydesmidan millipedes found primarily in North America. Members of this tribe are characterized by specific gonopodal modifications that distinguish them from related tribes within Rhysodesminae.
Orophe
Orophe is a genus of robust millipedes in the family Xystodesmidae, endemic to the Rocky Mountains of northern Idaho and western Montana. The genus contains two species: Orophe unicus and Orophe cabinetus. Both species are large-bodied with similar coloration featuring yellow paranota and central yellow patches on the tergites, differing only in gonopod morphology.
Orophe unicus
Orophe unicus is a robust millipede in the family Xystodesmidae endemic to the Rocky Mountains of northern Idaho. Originally described as Chipus unicus in 1953, it was transferred to Orophe in 1964 and has undergone taxonomic revision due to its close similarity to Orophe cabinetus. The species is distinguished from its sister species primarily by subtle differences in gonopod structure and by geographic separation, though recent observations suggest their ranges may be closer than previously recognized.
Pachydesmus crassicutis
Pachydesmus crassicutis is a species of flat-backed millipede in the family Xystodesmidae, first described by Wood in 1864. The species is recognized as having eight subspecies, indicating considerable geographic variation across its range. It belongs to the order Polydesmida, the largest order of millipedes, characterized by their flattened body form. The species is part of a genus containing multiple species distributed in North America.
Pleuroloma
Pleurolomas
Pleuroloma is a genus of flat-backed millipedes in the family Xystodesmidae, distinguished by its great age, extensive geographic range, and ecological adaptability. The genus comprises four recognized species, with P. flavipes being the most widespread, ranging from the eastern Atlantic Coast to the central Great Plains. Members exhibit distinctive aggregating and migrating behaviors, particularly P. flavipes, which may contribute to its broad distribution. The genus is unique within Xystodesmidae for these behavioral traits and its ability to colonize diverse habitats.
Rhysodesmus texicolens
Rhysodesmus texicolens is a flat-backed millipede in the family Xystodesmidae. First described by Chamberlin in 1938, it is currently treated as a synonym of Aporiaria texicolens in some taxonomic databases. The species has been documented in Texas and is part of a diverse genus of polydesmidan millipedes found in North America.
Rudiloria
Rudiloria is a genus of flat-backed millipedes in the family Xystodesmidae, endemic to eastern North America. The genus contains seven described species, including the widespread R. trimaculata. Members are characterized by their flattened bodies and distinct color patterns. The genus was established by Causey in 1955.
Rudiloria trimaculata
Bob's Yellow and Black Millipede
Rudiloria trimaculata is a flat-backed millipede in the family Xystodesmidae, recognized by the proposed common name Bob's Yellow and Black Millipede. The species occurs in the northeastern United States and southeastern Canada. Two subspecies are recognized: R. t. trimaculata and R. t. tortua.
Semijulistus flavipes
Semijulistus flavipes is a flat-backed millipede in the family Xystodesmidae, order Polydesmida. The species was formerly classified under the genus Pleuroloma, and taxonomic revisions have placed it in Semijulistus. Like other xystodesmid millipedes, it produces hydrogen cyanide (HCN) as a chemical defense. The specific epithet "flavipes" refers to yellow leg coloration.
Sigmoria aequalis
Sigmoria aequalis is a species of flat-backed millipede in the family Xystodesmidae, described by Shelley in 1981. It belongs to the order Polydesmida, a large and diverse group of millipedes characterized by their flattened body form. The genus Sigmoria is part of the tribe Apheloriini within the subfamily Rhysodesminae, a predominantly North American lineage of xystodesmid millipedes.
Thrinaphe
Thrinaphe is a genus of flat-backed millipedes in the family Xystodesmidae, containing a single described species, T. hargeri. The genus was established by Rowland M. Shelley in 1993 based on specimens from the Cascade Mountains and Willamette Valley region. The name references the three-branched telopodite of the male gonopod and its similarity to the related genus Harpaphe.
Xystocheir brachymacris
Xystocheir brachymacris is a species of flat-backed millipede in the family Xystodesmidae, native to North America. Like other members of its family, it possesses chemical defense glands capable of producing hydrogen cyanide gas when disturbed. The species was described by Shelley in 1996.
Xystocheir dissecta
Xystocheir dissecta is a flat-backed millipede in the family Xystodesmidae. It is found along the coast of Northern California, particularly in and around the San Francisco Bay Area. The species is notable for its chemical defense system, producing hydrogen cyanide gas when threatened. Three subspecies are recognized: X. d. dissecta, X. d. microrama, and X. d. taibona.
Xystocheir dissecta taibona
Xystocheir dissecta taibona is a subspecies of flat-backed millipede in the family Xystodesmidae. It is a synonym of Xystocheir taibona and is known from California. Like other members of its genus, it produces cyanide as a chemical defense against predators. The subspecies is documented as prey for the specialized carabid beetle Promecognathus.
Xystodesmini
Xystodesmini is a tribe of flat-backed millipedes within the family Xystodesmidae, order Polydesmida. The tribe was established by Hoffman in 1978 and contains multiple genera of medium to large-sized millipedes found primarily in North America. Members are characterized by their flattened bodies with lateral extensions (paranota) and often display aposematic coloration. The tribe is well-represented in citizen science observations, with over 18,000 records on iNaturalist.