''Polydesmus angustus'', also known as the flat-backed millipede, is a

millipede Millipedes (originating from the Latin , "thousand", and , "foot") 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 derive ...

in the genus ''

Polydesmus ''Polydesmus'' is a genus of millipedes in the family Polydesmidae. With more than 200 species and subspecies, this genus is the largest in this family. This genus has a Palearctic distribution, with species found mainly in the Mediterranean re ...

'' native to

Western Europe Western Europe is the western region of Europe. The region's extent varies depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the Western half of the ancient Mediterranean ...

Description

The flat-backed millipede can be a rather small species of millipede, while typically reaching , in captivity there have been individuals that reached sizes of up to or as small as , 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

gonopod Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipe ...

s or female

epigyne The epigyne or epigynum is the external genital structure of female spiders. As the epigyne varies greatly in form in different species, even in closely related ones, it often provides the most distinctive characteristic for recognizing species. ...

Range and habitat

''Polydesmus angustus'' is most commonly found in

, including the

British Isles The British Isles are an archipelago in the Atlantic Ocean, North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner Hebrides, Inner and Outer Hebr ...

; with some sightings in the East and West of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and southern

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

; likely in an invasive capacity. It's often been believed that the flat-headed millipede prefers a woodland habitat, seen as they can be found in their leaf litter; more recent analysis suggest the species' true preference of

heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and is characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a coole ...

and

moorland Moorland or moor is a type of Habitat (ecology), habitat found in upland (geology), upland areas in temperate grasslands, savannas, and shrublands and the biomes of montane grasslands and shrublands, characterised by low-growing vegetation on So ...

environments, due to its tendency towards peat soils and dislike of soils with over 45% clay.

References

External links

ecowatch_diplopoda
Polydesmida Millipedes of Europe Animals described in 1884 {{Millipede-stub