| Polydesmus angustus | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Myriapoda |
| Class: | Diplopoda |
| Order: | Polydesmida |
| Family: | Polydesmidae |
| Genus: | Polydesmus |
| Species: | P. angustus |
| Binomial name | |
| Polydesmus angustus | |
Polydesmus angustus, also known as the flat-backed millipede, is a millipede in the genus Polydesmus native to Western Europe. [2] [3]
The flat-backed millipede can be a rather small species of millipede, while typically reaching 24 millimetres (0.94 in), in captivity there have been individuals that reached sixes of up to 50 millimetres (2.0 in) or as small as 18 millimetres (0.71 in), this grand variety has been attributed to the quality of nutrition and humidity. As the name points out, Polydesmus angustus is a rather flat millipede, with all 20 segments' chitin extending laterally, an adaptation for digging and camouflaging in leaf litter. They are quite similar to other species in their same genus, P. coriaceus, P. denticulatus and P. inconstans, only being reliably identified by the shape of a male's gonopods or female epigyne. [2] [4] [5]
Polydesmus angustus is most commonly found in Western Europe, including the British Isles; [2] [6] with some sightings in the East and West of the United States and southern Canada; likely in an invasive capacity. [5] [7]
It's often been believed that the flat-headed millipede prefers a woodland habitat, seen as they can be found in their leaf litter; [8] more recent analysis suggest the species' true preference of heath and moorland environments, due to its tendency towards peat soils and dislike of soils with over 45% clay. [9]
Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a result of two single segments fused together. Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a tight ball. Although the name "millipede" derives from Latin for "thousand feet", no species was known to have 1,000 or more until the discovery in 2020 of Eumillipes persephone, which can have over 1,300 legs. There are approximately 12,000 named species classified into 16 orders and around 140 families, making Diplopoda the largest class of myriapods, an arthropod group which also includes centipedes and other multi-legged creatures.
Pill millipedes are any members of two living orders of millipedes, often grouped together into a single superorder, Oniscomorpha. The name Oniscomorpha refers to the millipedes' resemblance to certain woodlice (Oniscidea), also called pillbugs or "roly-polies". However, millipedes and woodlice are not closely related ; rather, this is a case of convergent evolution.
Tachypodoiulus niger, known variously as the white-legged snake millipede or the black millipede, is a European species of millipede. It is very similar to other species such as Cylindroiulus londinensis, from which it can be reliably distinguished only by studying the shape of the telson. It occurs in Ireland, Britain, Spain, France, Benelux, Germany, Switzerland, Austria and the Czech Republic, and is especially common on chalky and limestone soils.
Glomerida is an order of pill-millipedes found primarily in the Northern Hemisphere. Also known as northern pill millipedes, they superficially resemble pill-bugs or woodlice, and can enroll into a protective ball. They have twelve body segments, 17 to 19 pairs of legs, and males have enlarged rear legs involved in mating. The order includes about 30 genera and at least 280 species, including Glomeris marginata, the common European pill-millipede. The order contains members in Europe, South-east Asia and the Americas from California to Guatemala. Although historically considered closely related with the similar sphaerotheriidans that also enroll, some DNA evidence suggest they may be more closely related to glomeridesmidans, a poorly known order that does not enroll.
Polydesmida is the largest order of millipedes, containing approximately 3,500 species, including all the millipedes reported to produce hydrogen cyanide (HCN). Polydesmids grow and develop through a series of moults, adding segments until they reach a fixed number in the adult stage, which is usually the same for a given sex in a given species, at which point the moulting and the addition of segments and legs stop. This mode of development, known as teloanamorphosis, distinguishes this order from most other orders of millipedes, which usually continue to moult as adults, developing through either euanamorphosis or hemianamorphosis.
Ommatoiulus moreleti, commonly known as the Portuguese millipede, is a herbivorous millipede native to the western Iberian Peninsula where it shares its range with other Ommatoiulus species. From here, it has spread by international commerce to a number of new localities. This species was accidentally introduced into Australia without its natural enemies and has since become an invasive pest. A number of methods have been developed to manage this millipede.
Sphaerotheriida is an order of millipedes in the infraclass Pentazonia, sometimes known as giant pill millipedes. They inhabit Southern Africa, Madagascar, South and Southeast Asia, Australia and New Zealand. Like the Northern Hemisphere pill millipedes of the order Glomerida, these millipedes can roll into a ball when disturbed. When they are rolled-up, most sphaerotheriidans reach a maximum size of a cherry or golf ball, but some species from Madagascar can even reach the size of an orange. When rolled-up, predators are unable to unravel giant pill millipedes since the margins of their second and last dorsal plates fit perfectly into one another, creating a sealed ball. A few giant pill millipede species are able to produce sound, the only millipedes known to do this. This order of millipedes is also unique in that some African species are used for medicinal purposes.
Sphaeromimus, or the chirping giant pill millipedes, is a genus of giant pill millipedes endemic to southeastern Madagascar. Though described in 1902, the genus was up to 2005 known from a single male specimen, whose appearance was so unusual that the authors suspected a mislabeled giant pill-millipede from India. Their unusual and distinct morphology includes well-developed stridulation organs, probably as devices for courtship. These are the male ‘harp’ and the female ‘washboard’, which contain more stridulation ribs than in other members of the order Sphaerotheriida. They have a closer affinity with the Indian genus Arthrosphaera than to other Malagasy genera, though all belong to the Arthrosphaeridae.
Xystodesmidae is a family of millipedes. Its members often have very small distributional areas, with many species only known from a single locality. They are found across the northern hemisphere, with peak diversity in the Appalachian Mountains, where one-third of the 300 or so species occur. They are particularly abundant in deciduous broadleaf forests in the Mediterranean Basin, Africa, Asia, Central and North America, and Russia. Information on basic taxonomy is scant for this family; for example, it is estimated that the genus Nannaria contains over 200 species, but only 25 were described as of 2006. By 2022, 78 species in Nannaria have been described.
Polyxenida is an order of millipedes readily distinguished by a unique body plan consisting of a soft, non-calcified body ornamented with tufts of bristles – traits that have inspired the common names "bristly millipedes" or "pincushion millipedes". There are at least 86 species in four families worldwide, and are the only living members of the subclass Penicillata.
Glomeridesmida is an order of millipedes in the infraclass Pentazonia containing 2 families and at least 31 species. Glomeridesmida is the only living order of the superorder Limacomorpha. Also known as slug millipedes, glomeridesmidans are small and somewhat flattened, and unlike other orders of Pentazonia, are unable to roll into a ball. Ocelli (eyes) are absent.
Platydesmida is an order of millipedes containing two families and over 60 species. Some species practice paternal care, in which males guard the eggs.
Siphoniulus is a poorly known genus of millipede containing only two living species: S. alba from Indonesia, and S. neotropicus from Mexico and Guatemala. An additional two fossil species are known from Cretaceous amber. Siphoniulus species are the only members of the family Siphoniulidae and order Siphoniulida, making Siphoniulida the smallest millipede order. Few specimens are known, and their classification is contentious, although most recent studies place them as basal members of the Helminthomorpha.
Glomeris connexa is a species of pill millipede within the genus Glomeris and family Glomeridae.
Glomeridesmidae is a millipede family of the order Glomeridesmida. This family includes two genera: The genus Glomeridesmus includes most species in this family; the genus Glomeridesmoides includes one species.
Kampecaris is an extinct genus comprising the Kampecarida, an enigmatic group of millipede-like arthropods, from the Silurian and early Devonian periods of Scotland and England. They are among the oldest known land-dwelling animals. They were small, short-bodied animals with three recognizable sections: an oval head divided along the midline, ten limb-bearing segments forming a cylindrical trunk that tapered slightly towards the front, and a characteristic swollen tail formed by a modified segment that tapers at its rear into an "anal segment". The cuticle forming their exoskeletons was thick, heavily calcified, and composed of two layers.
Metopidiotrichidae is a family of millipedes in the order Chordeumatida. These millipedes range from 4 mm to 17 mm in length. Adult millipedes in this family have 32 segments, not the 30 segments usually found in this order. Adult males in this family often feature a reduced or vestigial leg pair 10 as part of the gonopod complex, in addition to the two leg pairs typically modified into gonopods in this order. There are about 9 genera and at least 70 described species in Metopidiotrichidae.
Glomeris ligurica is a species of pill millipede within the genus Glomeris and family Glomeridae.
Anthogona britannica is a species of millipede in the genus Anthogona, endemic to the British Isles, where it is nationally rare and has an International Union for Conservation of Nature status of "near threatened".
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