Sphaeromimus
Encyclopedia
Sphaeromimus, or the chirping giant pill millipedes, is a genus of giant pill millipedes (order Sphaerotheriida
) endemic to southeastern Madagascar
. The genus was first described by Henri Louis Frédéric de Saussure and Leo Zehntner in 1902 but until 2005 was known only from a single male, whose appearance was so unusual that the authors thought it might represent a mislabeled giant pill millipede from India. It belongs to the family
Arthrosphaeridae, which besides Sphaeromimus includes the Malagasy genera Zoosphaerium and Microsphaerotherium and the Indian genus Arthrosphaera. Recent research has shown that Sphaeromimus is more closely related to the Indian genus Arthrosphaera than to other Malagasy genera. Three species have been described within Sphaeromimus, S. musicus, S. splendidus, and S. inexpectatus, although some undescribed species have been found recently. All populations inhabit the leaf litter of the Malagasy rainforests, except for one undescribed species which was found in a cave and the type species
S. musicus which has only been found in the dry spiny forest
. Recent research has shown that Sphaeromimus populations are highly endemic, since individuals are not able to travel between forest patches. Movement between populations is becoming more limited, as forest is being destroyed at a rapid rate on Madagascar.
Like other giant pill millipedes, Sphaeromimus individuals can roll up into a ball for protection. The size of this ball is typically equal to that of a ping-pong ball and can sometimes even be larger. Males have a structure on their anterior telopod, known as the harp, which has several stridulation
ribs and is able to produce sounds when rubbed against a sclerotized knob on the leg. They probably use this structure during courtship in order to prevent females from rolling up into a ball. When a female is receptive, it is believed that males use their posterior telopods in order to hold her down for copulation. Females, on the other hand, have a structure on their subanal plate called the washboard, which, like the male harp, contains stridulation ribs and produces sounds. The harp and washboard are present in all species of the family Arthrosphaeridae but are especially well developed in Sphaeromimus, with males having 3–7 ribs on each harp, and females 8–16 ribs on each washboard.
Sphaerotheriida
Sphaerotheriida is an order of millipedes in the subclass Pentazonia, sometimes known as giant pill millipedes. They inhabit the Southern Hemisphere. Like the Northern Hemisphere pill millipedes of the order Glomerida, these millipedes can roll into a ball when disturbed...
) endemic to southeastern Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. The genus was first described by Henri Louis Frédéric de Saussure and Leo Zehntner in 1902 but until 2005 was known only from a single male, whose appearance was so unusual that the authors thought it might represent a mislabeled giant pill millipede from India. It belongs to the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Arthrosphaeridae, which besides Sphaeromimus includes the Malagasy genera Zoosphaerium and Microsphaerotherium and the Indian genus Arthrosphaera. Recent research has shown that Sphaeromimus is more closely related to the Indian genus Arthrosphaera than to other Malagasy genera. Three species have been described within Sphaeromimus, S. musicus, S. splendidus, and S. inexpectatus, although some undescribed species have been found recently. All populations inhabit the leaf litter of the Malagasy rainforests, except for one undescribed species which was found in a cave and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
S. musicus which has only been found in the dry spiny forest
Madagascar spiny thickets
The Madagascar spiny thickets is an ecoregion in Madagascar. The vegetation type is found on poor substrates with low, erratic winter rainfall. An estimated 14,000 to is covered with this habitat, all in the southwest of the country...
. Recent research has shown that Sphaeromimus populations are highly endemic, since individuals are not able to travel between forest patches. Movement between populations is becoming more limited, as forest is being destroyed at a rapid rate on Madagascar.
Like other giant pill millipedes, Sphaeromimus individuals can roll up into a ball for protection. The size of this ball is typically equal to that of a ping-pong ball and can sometimes even be larger. Males have a structure on their anterior telopod, known as the harp, which has several stridulation
Stridulation
Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fishes, snakes and spiders...
ribs and is able to produce sounds when rubbed against a sclerotized knob on the leg. They probably use this structure during courtship in order to prevent females from rolling up into a ball. When a female is receptive, it is believed that males use their posterior telopods in order to hold her down for copulation. Females, on the other hand, have a structure on their subanal plate called the washboard, which, like the male harp, contains stridulation ribs and produces sounds. The harp and washboard are present in all species of the family Arthrosphaeridae but are especially well developed in Sphaeromimus, with males having 3–7 ribs on each harp, and females 8–16 ribs on each washboard.