User:Stephanie Loria/Giant Pill-Millipede

Giant Pill-Millipedes (Order Sphaerotheriida)

* There is already an article named Sphaerotheriida in the mainspace.

This page is about the type of animal. For other uses, see Stephanie Loria/Giant Pill-Millipede (disambiguation).

Giant Pill-Millipede
Pill Millipede, Spherotheriida
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Diplopoda
Order:	Sphaerotheriida
Distribution
15
File:Distribution-Sphaerotheriida.jpeg
Range of the Giant Pill-Millipedes(green)

Order Sphaerotheriida Brandt, 1833 (Class Diplopoda, Millipedes)

Synonym: Chorizocerata Verhoeff

Families:
Arthrosphaeridae
Procyliosomatidae
Sphaerotheriidae
Zephronidae

Giant Pill-Millipedes (order Sphaerotheriida, Latin from sphaerium = ball) is an order of millipedes in the subclass Pentazonia. inhabiting the Southern Hemisphere. Like the Northern Hemisphere Pill-Millipedes (order Glomerida), these millipedes can roll into a perfect ball when disturbed. When they are rolled-up, most Sphaerotheriids reach a maximum size of a cherry or golf ball, but some species from Madagascar can even reach the size of a baseball or an example of Island Gigantism). When rolled-up, predators are unable to unravel Giant-Pill Millipedes since the margins of their second and last dorsal plate fit perfectly into one another creating a sealed ball. A few Giant Pill-Millipede species are able to produce sound, being the only millipede taxa known to do this or an example of Island Gigantism). This order of millipedes is also unique since some African species are used for medicinal purposes.

Morphology

The Sphaerotheriida are characterized by a relatively conservative body morphology; superficially all species and genera look the same. Like the Northern Hemisphere Pill-Millipedes. Dorsally, their head is followed by twelve body tergites (collum, thoracic shield, and ten normal tergites) and the anal shield. Ventrally, females possess twenty-one leg pairs (forty-two legs in total), while males carry two additional modified leg pairs, the anterior and posterior telopods under their anal shield. The telopods resemble chelae and/or clamp-like structures, which are probably used in holding the female during mating. Like the Northern Hemisphere Pill-Millipedes. In the position of the male telopods, the females instead have a sclerotized subanal plate, which in some species such as those belonging to the family Arthrosphaeridae, is enlarged and is used to produce vibrations ([[stridulation]). Like the Northern Hemisphere Pill-Millipedes Furthermore unlike other large-bodied millipede orders, Sphaerotheriida do not have repugnatorial glands which excrete poisonous or ill-smelling substances. Therefore, they entirely depend on their rolling-up behavior for protection.

Sphaerotheriida somewhat resemble the North American and Euro-Asian Pill-Millipedes of the order Glomerida, but are generally larger in size (20-80 mm body length) with only the smallest Sphaerotheriida species being as large as the largest members of the order Glomerida. The orders differ in the number of tergites (10 or 11 in Glomerida, 12 in Sphaerotheriida) and legs (17/19 in Glomerida, 21/23 in Sphaerotheriida), and show great differences in their head morphology and genital openings, among other characters. Both orders have the ability to roll into a perfect ball, protecting the head, antenna, and the vulnerable underside. However, this rolled-up position (volvation) is achieved differently. In Glomerida, the enlarged second body ring (thoracic shield) has a more or less well-visible gap where the tips of tergites 3–11 fit inside, whereas in Sphaerotheriida the tips of tergites 3-12 fit perfectly into a groove on the thoracic shield. Interestingly, juvenile Sphaerotheriids show the same gap as the Glomerida. Many Giant Pill-Millipede species have special ledges ('locking carinae') on the underside of the tergite tips and the anal shield which can be moved above a brim on the thoracic shield. This permits the millipedes to remain passively locked-up and not stretch their muscles permanently.

On Madagascar, some Giant Pill-Millipede species exhibit Island Gigantism, reaching a size comparable to a tennis ball, baseball or even small orange when rolled-up. Recently, an example of Island Dwarfism was also described from Madagascar: full-grown individuals of the species Microsphaerotherium ivohibiense being just the size of a pea.

Distribution

In general, Sphaerotherrids are found only in the South Hemisphere and their distribution mirrors that of a Gondwanan distribution. Gondwana was the large continent that formed to the south after the breakup of the supercontinent Pangaea. It included the modern-day landmasses of South America, New Zealand, Australia, India, and Madagascar. It is believed that the Sphaerotheriida originated in Gondwana and then diverged into its various forms. Currently, 322 species in 23 genera are known with numerous new species having been discovered recently. The Sphaerotheriids are divided into four families whose distributions do not overlap. These include Procyliosomatidae, Zephronidae, Sphaerotheriidae and Arthrosphaeridae. The basal most family, Procyliosomatidae, lives in Australia and New Zealand. The Zephronidae (synonym Sphaeropoeidae) occurs in southeast Asia spanning from the Himalayas and China north to Sulawesi and inhabits some Philippines Islands to the south. The family Sphaerotheriidae only occurs in southern Africa with isolated populations in Zimbabwe and Malawi (probably introduced). The Arthrosphaeridae are distributed in southern India and Madagascar.
A few Giant Pill-Millipede species have been dispersed by humans. Examples include the Sri Lankan Arthrosphaeridae species A. brandtii which established a population in the Usambara hills, Tanzania, Africa, as well as some South African Sphaerotherium species which have isolated populations in Malawi. Another likely candidate is Sechelliosoma forcipatum, a small species of the southeast Asian family Zephronidae, currently only known from a single Seychellois island.

Ecology

Little is known about the ecology, development and life history of Sphaerotheriids, but all species are most likely detritovores, feeding on dead organic matter such as leaves and wood on the forest floor. Giant Pill-Millipedes, like earthworms, play an important role in decomposition, releasing nutrients that are locked up in decaying organic matter back into the soil. This process is essential for plant nutrition. It is possible that Giant Pill-Millipedes use special bacteria in their gut, similar to the way termites do, to get energy out of non-easily digestible material such as lignin.

Like most millipedes, Sphaerotheriids mainly inhabit the leaf litter of humid forests. Some species, however, show an arboreal (tree-living) lifestyle and for these organisms the rolling-up reflex has been suppressed..

Defense against Predation

Giant-Pill Millipedes are predated on by a wide variety of organisms and their rolling-up ability seems to be a good defense against most predators. Only a few animals specialize on feeding on Giant Pill-Millipedes and as a result have evolved special structures or behaviors to overcome their defensive mechanism. Examples include the South African snail family Chlamydephoridae which almost exclusively feeds on Giant Pill-Millipedes along with meerkats (Suricata suricata) which have been reported (at least in captivity) to throw rolled-up Sphaerotheriids against rocks in order to break them. Besides their rolling-up behavior, it has been suggested that camouflage may be another defense mechanism that Giant-Pill Millipedes use specifically to protect them from animals that hunt using vision, such as birds. Sphaerotheriids also need to cope with internal parasites, with several species of nematodes living in them exclusively.

Giant Pill-Millipedes as Pets

Sphaerotheriids are commonly found in the pet trade and are kept by terraristic enthusiasts in Japan, Europe, and the United States. The species usually either come from Madagascar or Malaysia. The survival rate for Giant Pill-Millipedes in captivity is quite low; they rarely live longer than a month. The reasons for their low survival rate in captivity is little understood. Some explanations include their reliance on low calorie foods, their susceptibility to parasites, their dependence on special climatic conditions (<75° F at day, <65° F at night), and weakness caused during transport. Since no captive breeding programs have been initiated, all animals found in stores are caught in the wild.

Taxonomy

• Family: Arthrosphaeridae
  

Arthrosphaera Pocock, 1895, 40 species, India, Sri Lanka

Zoosphaerium Pocock, 1895, 55 species, Madagascar

Sphaeromimus de Saussure & Zehntner, 1902, 3 species, southeast Madagascar

Microsphaerotherium Wesener & van den Spiegel, 2007, 2 species, Madagascar

• Family: Procyliosomatidae
  

Procyliosoma, Silvestri, 1917: 11 species, Eastern Australia, Tasmania, New Zealand

• Family: Zephronidae
  

Bothrobelum Verhoeff, 1924, monotypic, Borneo

Cryxus Leach, 1814, monotypic, 'Asia'

Indosphaera Attems, 1935, 2 species N. India, Myanmar

Kophosphaera Attems, 1935, 5 species, N. India, Nepal

Leptotelopus Silvestri, 1897, monotypic, Myanmar

Prionobelum Verhoeff, 1924, 8 species, Vietnam, SW China

Sphaerobelum Verhoeff, 1924, 4 species, Vietnam

Zephronia Gray, 1832, 37 species N. India, Myanmar, Malayan Peninsula, Java, Sumatra, Borneo

Sphaeropoeus Brandt, 1833, 22 species, N. India, Myanmar, Malayan Peninsula, Java, Sumatra, Borneo

Tigridosphaera Jeekel, 2000, 4 species, Malayan Peninsula

Castanotherium Pocock, 1895, 50 species, Indonesian Islands, Philippines

Castanotheroides Chamberlin, 1921, 3 species, Philippines

Sechelliosoma Mauriès, 1980, monotypic, Seychelles

Rajasphaera Attems, 1935, monotypic, Borneo

• Family: Sphaerotheriidae

Sphaerotherium Brandt, 1833, 54 species, South Africa, Zimbabwe

Kylindotherium Attems, 1926, monotypic, South Africa

• Incertae Sedis
  

Epicyliosoma Silvestri, 1917, 15 species, Australia

Cynotelopus Jeekel, 1986, monotypic, southwest Australia