Polyzoniida

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Myriapoda
Classis: Diplopoda
Subclassis: Chilognatha
Infraclassis: Helminthomorpha
Superordo: Ommatophora
Ordo: Polyzoniida
Familiae: Hirudisomatidae - Polyzoniidae - Siphonotidae - Siphonocryptidae
Vernacular names
日本語: ジヤスデ目

Polyzoniida is an order of millipedes in the subterclass Colobognatha containing three families and at least 74 described species.[1]
Description
Male Bdellozonium cerviculatum from the western United States viewed from below and above

Polyzoniidans have a somewhat domed dorsal surface with a flat ventral side. Their heads are small and cone-like, with few ocelli. They lack a dorsal groove and paranota (lateral extensions of each segment).[2]
Classification

The order Polyzoniida contains three families:[1]

Hirudisomatidae Silvestri, 1896 (6 genera, 20 species)
Polyzoniidae Newport, 1844 (6 genera, 22 species)
Siphonotidae Cook, 1895 (15 genera, 40 species)

Distribution

The family Hirudisomatidae occurs from Spain to the Himalayas in Eurasia, Japan, and in North America from southwest Canada to central Mexico.
Polyzoniidae has a holarctic (northern hemisphere) distribution, occurring in the northwest and northeast United States, eastern Canada, and in Europe from the United Kingdom and France to Siberia.
Siphonotidae has a southern distribution, occurring in Brazil and Chile, South Africa, Southeast Asia, Indonesia, Tasmania, and New Zealand.[3][4]
References

Shear, W. (2011). "Class Diplopoda de Blainville in Gervais, 1844" (PDF). In Zhang, Z.-Q. (ed.). Animal biodiversity: an outline of higher-level classification and survey of taxonomic richness. Zootaxa. Vol. 3148. pp. 159–164. ISBN 978-1-86977-850-7.
"Diagnostic features of Millipede Orders" (PDF). Milli-PEET Identification Tables. The Field Museum, Chicago. Retrieved 25 October 2013.
"Geographic distribution of Millipede Families" (PDF). Milli-PEET Identification Tables. The Field Museum, Chicago. Retrieved 25 October 2013.
Mesibov, Robert. "Millipede species: Polyzoniida". Tasmanian Multipedes. Retrieved 14 November 2013.