Pill millipede

Pill millipedes
Glomeris marginata
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Myriapoda
Class:	Diplopoda
Superorder:	Oniscomorpha Pocock, 1887 [1]
Orders
Glomerida Sphaerotheriida
Synonyms
Armadillomorpha Verhoeff, 1915

Pill millipedes make up two orders of millipedes, often grouped together into a single superorder, Oniscomorpha. The name Oniscomorpha refers to the resemblance of pill millipedes to certain woodlice, namely the pillbugs of the family Armadillidiidae, also called "potato bugs", "doodlebugs", or "roly-polies". However, they are only distantly related.

Pill millipedes are short compared to other millipedes, with only eleven to thirteen body segments,^[2] and are capable of rolling into a ball when disturbed. This ability may however have evolved separately in each of the two orders, making it a case of convergent evolution, rather than homology.^[3] Pill millipedes are detritivorous, feeding on decomposing plant matter, usually in woodlands.^[4]

A comparison of a pillbug (above: Armadillidium vulgare) and a pill millipede (below: Glomeris marginata)

Orders

Glomerida

The Order Glomerida is found in the Northern Hemisphere and includes species such as Glomeris marginata, the common European pill millipede. They have from eleven to twelve body segments, and lack the defensive repugnatorial glands found on many other millipedes. The order contains members in Europe, South-east Asia and the Americas from California to Guatemala.^[5] Three species are present in the British Isles.^[6]

Sphaerotheriida

Main article: Sphaerotheriida

The Order Sphaerotheriida is a Gondwana-distribution taxon, with around 100 species in southern Africa, Madagascar,^[7] Australasia^[8] and South East Asia.^[5] They have thirteen body segments, and do not possess repugnatorial glands. Five species, all in the genus Procyliosoma are present in New Zealand,^[8] and around thirty species in three or more genera are present in Australia.^[9]

References

1. ^ "Millipedes". myriapoda.org. March 10, 2005. http://www.myriapoda.org/images.html. 
2. ^ P. R. Racheboeuf, J. T. Hannibal & J. Vannier (2004). "A new species of the diplopod Anymilyspes (Oniscomorpha) from the Stephania lagerstätte of Montceau-les-Mines, France". Journal of Paleontology 78 (1): 221–229. doi:10.1666/0022-3360(2004)078<0221:ANSOTD>2.0.CO;2. ISSN 0022-3360. http://jpaleontol.geoscienceworld.org/cgi/content/extract/78/1/221. 
3. ^ "Defining Features of Nominal Clades of Diplopoda" (PDF). Field Museum of Natural History. http://www.fieldmuseum.org/research_collections/zoology/zoo_sites/millipeet/pdfsFullarticles/system_12.pdf. Retrieved June 24, 2007. 
4. ^ "Pill millipedes fact file". Australian Museum. Archived from the original on August 29, 2007. http://web.archive.org/web/20070829154458/http://faunanet.gov.au/wos/factfile.cfm?Fact_ID=105. Retrieved June 24, 2007. 
5. ^ ^{a b} "Biogeography of millipede families" (PDF). Field Museum of Natural History. http://www.fieldmuseum.org/research_collections/zoology/zoo_sites/millipeet/pdfsFullarticles/MP10Table3.pdf. Retrieved June 24, 2007. 
6. ^ Paul Lee (October 11, 2006). "Checklist of species of millipedes in Britain and Ireland". British Myriapod and Isopod Group. http://mysite.orange.co.uk/bmig/html/millipede.html. 
7. ^ T. Wesener, I. Bespalova & P. Sierwald (2010). "Madagascar's living giants: discovery of five new species of endemic giant pill-millipedes from Madagascar (Diplopoda: Sphaerotheriida: Arthrosphaeridae: Zoosphaerium)". African Invertebrates 51 (1): 133–161. http://www.africaninvertebrates.org.za/Wesener_etal_2010_51_1_466.aspx. 
8. ^ ^{a b} M. A. Minor & A.W. Robertson (May 7, 2007). "Diplopoda". Guide to New Zealand soil invertebrates. Massey University. http://soilbugs.massey.ac.nz/diplopoda.php. 
9. ^ "Checklist for Sphaerotheriida Brandt, 1833". Australian Faunal Directory. Department of the Environment and Water Resources. http://www.environment.gov.au/biodiversity/abrs/online-resources/fauna/afd/taxa/SPHAEROTHERIIDA/checklist#selected. Retrieved November 7, 2010.