Millipede
Guides
Sigmocheir
Sigmocheir is a genus of flat-backed millipedes in the family Xystodesmidae, endemic to the foothills of the Sierra Nevada mountains in California. The genus contains three species: S. maculifer, S. calaveras, and S. furcata. All species share a distinctive color pattern of three lemon yellow spots per segment. The genus was established by R.V. Chamberlin in 1951, with a complex taxonomic history involving synonymies that were not fully resolved until 1995.
Sigmocheirini
Sigmocheirini is a tribe of flat-backed millipedes (Order Polydesmida) in the family Xystodesmidae, established by Causey in 1955. The tribe contains the genus Sigmocheir, whose species are endemic to California's Sierra Nevada foothills. Members of this tribe exhibit the characteristic flattened body form typical of xystodesmid millipedes.
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.
Sigmoria australis
Sigmoria australis is a flat-backed millipede in the family Xystodesmidae, described by Shelley in 1986. It belongs to the order Polydesmida, a group characterized by their dorsoventrally flattened bodies and distinct lateral extensions (paranota) on each segment. The species is known from North America, with confirmed records from Florida.
Sigmoria bidens
Sigmoria bidens is a species of flat-backed millipede in the family Xystodesmidae, described by Causey in 1942. It belongs to the order Polydesmida, one of the largest orders of millipedes, characterized by their flattened bodies and keeled tergites. The genus Sigmoria is part of the tribe Apheloriini within the subfamily Rhysodesminae. Very few observations of this species have been documented, with only 8 records in iNaturalist as of the knowledge cutoff.
Sigmoria latior
Red-sided Flat Millipede
Sigmoria latior is a flat-backed millipede in the family Xystodesmidae, commonly known as the Red-sided Flat Millipede. The species was described by Brölemann in 1900 and is native to North America. Four subspecies are recognized, including the nominate subspecies S. l. latior and S. l. hoffmani, S. l. mariona, and S. l. munda. As a member of the tribe Apheloriini, it belongs to a group of xystodesmid millipedes known for their often striking coloration.
Sigmoria nantahalae
Nantahala Cherry Millipede
Sigmoria nantahalae is a species of flat-backed millipede in the family Xystodesmidae, first described by Hoffman in 1958. It is endemic to the southern Appalachian Mountains of North America, with confirmed records from North Carolina. The species belongs to the tribe Apheloriini, a group known for producing hydrogen cyanide as a defensive secretion.
Sigmoria plancus
Sigmoria plancus is a species of flat-backed millipede in the family Xystodesmidae, first described by Loomis in 1944. It belongs to a genus of eastern North American polydesmid millipedes characterized by distinctive color patterns and defensive chemical secretions. The species is part of a taxonomically complex group where species boundaries and distributions remain incompletely documented.
Siphonophorida
Snout Millipedes
Siphonophorida is an order of millipedes in the subclass Colobognatha containing two families: Siphonophoridae and Siphonorhinidae. These millipedes are characterized by super-elongated, worm-like bodies with up to 190 segments and extreme numbers of legs—up to 750 in Illacme plenipes, the leggiest animal known. They lack eyes and exhibit euanamorphosis, adding segments throughout life even after sexual maturity. The order shows a scattered, disjunct distribution across multiple continents including North America, South America, Africa, Madagascar, India, Southeast Asia, and Australia.
Siphonorhinidae
Siphonorhinidae is a family of millipedes in the order Siphonophorida, characterized by super-elongated trunks with more than 180 diplosegments and leg counts exceeding 710 in some species. The family includes the leggiest animal on Earth, Illacme plenipes, with females possessing up to 750 legs. Members are small, threadlike, slow-moving, unpigmented, and inhabit deep soil microhabitats. The family exhibits a fragmentary, disjunct distribution across California, southern Africa, Madagascar, the Malay Archipelago, Indo-Burma, and now Chile. Siphonorhinidae is represented in the Western Hemisphere solely by the genus Illacme in California and the newly described genus Notorhinus in Chile.
Siphonotidae
Siphonotidae is a family of millipedes in the order Polyzoniida, established by Cook in 1895. The family comprises more than 70 species across 13 genera. These millipedes are distinguished by a narrow telson and active, quick movement. Members are distributed across the Southern Hemisphere in South America, South Africa, Madagascar, Southeast Asia, Australia, and New Zealand.
Spirostreptida
Spirostreptida is an order of large, cylindrical millipedes containing approximately 1000 described species, making it the third largest order of millipedes. Members are characterized by their elongated bodies with 30 to 90 body rings and generally large size, including the longest known millipedes such as the giant African millipedes of genus Archispirostreptus, which may exceed 30 cm. The order is divided into two suborders, Cambalidea and Spirostreptidea, with most species occurring in tropical and subtropical regions. Spirostreptida are primarily soil-dwelling detritivores, though some species inhabit caves.
Spirostreptidae
Flatplate Millipedes
Spirostreptidae is a family of large millipedes in the order Spirostreptida, commonly known as flatplate millipedes. The family comprises approximately 100 genera distributed across tropical and subtropical regions of the Americas, Africa, Madagascar, Seychelles, and the eastern Mediterranean. Members are characterized by their elongated cylindrical bodies and are primarily soil-dwelling detritivores, though some species exhibit arboreal habits. The family includes both synanthropic species that can become urban pests and species with specialized thermoregulatory and social behaviors.
Striaria
Striaria is a genus of millipedes in the family Striariidae, order Chordeumatida. The genus was established by Bollman in 1888. These small, eyeless millipedes are part of the diverse soil-dwelling fauna of temperate forests. The name Striaria is also used for a genus of brown algae (Phaeophyceae), but this represents a separate taxonomic entity in a different kingdom.
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.
Thrinaphe hargeri
Thrinaphe hargeri is a millipede species and the sole member of the genus Thrinaphe, described by Rowland M. Shelley in 1993. The species is endemic to the Cascade Mountains region along the Washington-Oregon border and the Willamette Valley in the Pacific Northwest of the United States. It belongs to the family Xystodesmidae, a diverse group of flat-backed millipedes.
Tidesmus
Tidesmus is a genus of small-bodied millipedes in the family Macrosternodesmidae, order Polydesmida. The genus was revised in 2007, with Phreatodesmus and Oodedesmus synonymized under it. It currently contains four valid species distributed in the southwestern United States and northwestern Mexico. The type species is T. episcopus Chamberlin, 1943.
Tidesmus episcopus
Tidesmus episcopus Chamberlin, 1943 is a small-bodied millipede and the type species of the genus Tidesmus (family Macrosternodesmidae). The species was originally described from western North America and is one of four recognized species in the genus. Phreatodesmus cooki Loomis, 1960 has been synonymized with this species. The family Macrosternodesmidae was redefined in a 2007 revision that clarified the generic placement of several western North American species.
Tingupidae
Tingupidae is a family of small millipedes in the order Chordeumatida, containing two genera (Blancosoma and Tingupa) and 13 described species. Adults possess 28 or 30 body segments including the collum and telson. The family occurs in western North America, with records extending from Alaska and British Columbia south to California and east to Arkansas.
Trichopetalidae
Trichopetalidae is a family of small millipedes in the order Chordeumatida. Adults possess 28 or 30 body segments, counting the collum as the first and the telson as the last. The family comprises seven genera and approximately 43 species, with members exhibiting diverse ecological strategies ranging from surface-dwelling to obligate cave-dwelling (troglobitic) lifestyles.
Trichopetalum
A genus of millipedes in the family Trichopetalidae, order Chordeumatida. Contains seven described species, all surface-dwelling or troglophilic. The genus is notable for the first documented authentic chordeumatidan spermatophores and the production of a sticky defensive secretion from segmental setae bases. Species occur in North America, primarily the United States.
Trichopetalum lunatum
Crescent Moon Millipede
Trichopetalum lunatum is a surface-dwelling or troglophilic millipede in the family Trichopetalidae, originally described by Harger in 1872. It is one of seven species in the genus Trichopetalum, which is distinguished from the fully troglobiotic genera Zygonopus and Scoterpes by its non-cave-adapted lifestyle. The species is known to produce a sticky secretion from the bases of its segmental setae, possibly serving a defensive function.
Trigoniulus
Asian millipede (informal, for T. corallinus)
Trigoniulus is a genus of millipedes in the family Trigoniulidae, established by Pocock in 1894. The genus contains at least 90 described species distributed primarily across tropical and subtropical regions of Asia. Species such as Trigoniulus corallinus and T. lumbricinus have been studied for their population ecology, revealing seasonal abundance patterns correlated with rainfall and temperature. The genus serves as a host for gut-associated microbes, including bacteria isolated from decaying plant habitats.
Trigoniulus corallinus
Rusty Millipede, Common Asian Millipede
Trigoniulus corallinus is a large millipede native to the Indo-Malayan region that has become established as an introduced species across multiple continents. Adults reach 50–75 mm in length and are characterized by a uniform reddish-brown coloration. The species inhabits moist terrestrial environments, particularly areas rich in decaying organic matter. It was the first millipede to have its genome sequenced (2015), and subsequent research has identified an XX/X0 sex chromosome system with males possessing modified seventh-leg pairs (gonopods) used for mating.
Tynomma
Tynomma is a genus of millipedes in the order Callipodida, family Tynommatidae. The genus was established by Loomis in 1937. Members of this genus are characterized by features typical of the Tynommatidae, including distinctive body segmentation and gonopod morphology. The genus occurs in western North America, with species documented from California and surrounding regions.
Underwoodia iuloides
Underwoodia iuloides is a millipede species in the family Caseyidae. It is one of three species in the genus Underwoodia, which exhibits a Holarctic distribution pattern. The species is characterized by specific configurations of the anterior gonopod colpocoxites, particularly branches a and c. Populations show a strongly female-biased sex ratio, suggesting parthenogenesis.
Vasingtona
Vasingtona is a genus of millipedes in the family Caseyidae, established by Chamberlin in 1941. The genus contains at least one described species, V. irritans. These millipedes belong to the order Chordeumatida, a group of small, often cryptic millipedes commonly known as snake millipedes or bristly millipedes.
Watichelus
Watichelus is a genus of millipedes in the family Atopetholidae, order Spirobolida. The genus was established by Chamberlin in 1949. Members of this genus are cylindrical, relatively large-bodied millipedes characteristic of the Spirobolida order. As a genus within Atopetholidae, Watichelus represents part of the diverse juliform millipede fauna of the Americas.
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.