Spirobolida

{{Short description|Order of millipedes}}

{{Distinguish|Spirostreptida}}

{{Automatic taxobox

| image = NarceusAmericanusMillipede.jpg

| image_caption = Narceus americanus

| taxon = Spirobolida

| authority = Bollman, 1893

| subdivision_ranks = Families

| subdivision = 12: See text

| synonyms = *Anocheta Cook, 1895

• Haplogonophora Brolemann, 1931

}}

Spirobolida is an order of "round-backed" millipedes containing approximately 500 species in 12 families.{{cite journal|last=Shear|first=W.|title=Class Diplopoda de Blainville in Gervais, 1844. In: Zhang, Z.-Q. (Ed.) Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness|journal=Zootaxa|year=2011|volume=3148|pages=159–164|url=http://www.mapress.com/zootaxa/2011/f/zt03148p164.pdf|ref=Shear2011}} Its members are distinguished by the presence of a "pronounced suture that runs "vertically down the front of the head".{{cite book |author=Stephen P. Hopkin & Helen J. Read |year=1992 |title=The Biology of millipedes |publisher=Oxford University Press |isbn=978-0-19-857699-0 |chapter=Taxonomy, evolution, and zoogeography |pages=8–23 |url=https://books.google.com/books?id=Yy6qPRtU5v0C&pg=PA11}} Most of the species live in the tropics, and many are brightly coloured. Mature males have two pairs of modified legs, the gonopods, consisting of the 8th and 9th leg pair: the posterior gonopods are used in sperm-transfer while the anterior gonopods are fused into a single plate-like structure.{{cite web|title=Putative apomorphies of millipede clades|url=http://fieldmuseum.org/sites/default/files/millipede_apomorphies.pdf|work=Milli-PEET: Millipede Systematics|publisher=The Field Museum, Chicago, IL|date=26 September 2006}}

File:Aphistogoniulus jeekeli holotype gonopods 02.png

The families are divided into two suborders:

Suborder Spirobolidea

• Allopocockiidae
• Atopetholidae
• Floridobolidae
• Hoffmanobolidae
• Messicobolidae
• Pseudospirobolellidae
• Rhinocricidae
• Spirobolellidae
• Spirobolidae
• Typhlobolellidae

Suborder Trigoniulidea

• Pachybolidae
• Trigoniulidae