Chordeumatida (from the Greek word for "sausage") is a large order of

millipede 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 resu ...

s containing some 1200 species with a nearly worldwide distribution. Also known as "sausage millipedes," they possess around 30 body segments behind the head (including the

telson The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on accou ...

) as adults and reach about in length.

Description

Chordeumatidans are relatively short-bodied, with only 26 to 32 body segments (including the telson) behind the head. They range in length from . A key feature is the presence of 6 large bristles (

setae In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

) on the dorsal surface of each body segment. The first segment ( collum) is relatively narrow, giving the appearance of a distinct "neck" in many species. The body tapers towards the rear, and the rearmost tip (telson) contains silk-producing organs (spinnerets). A dorsal groove runs down the length of the body, and some species possess paranota, lateral extensions of the exoskeleton. Paranota are also found in some other millipedes, notably

Polydesmida Polydesmida (from the Greek language, Greek ''poly'' "many" and ''desmos'' "bond") is the largest order (biology), order of millipedes, containing approximately 3,500 species, including all the millipedes reported to produce hydrogen cyanide (HCN ...

, from which Chordeumatidans can be distinguished by having a dorsal groove. Unlike most other helminthomorph (worm-like) millipedes, chordeumatidans lack

ozopore An ozopore is the opening of a defensive gland present in some arthropods, notably in millipedes of the order Polydesmida In adult males in this order, two leg pairs (pair 8 and pair 9) are modified into

gonopods 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 milli ...

, leaving 48 pair of walking legs in the typical adult male chordeaumatidan. Many species in this order, however, deviate from this typical body plan. Many species in this order deviate from the usual 30 segments: a few species have 26 segments as adults (e.g., ''Chamaesoma broelemanni''), many species have 28 (e.g., ''Lipseuma josianae''), one genus features 29 (''Tianella'', in which all but two species have 29), one species (''Metamastigophorophyllon martensi'') features 31, and many species have 32 (e.g., ''Altajosoma kemerovo''). Some species also deviate by featuring

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

in segment number, specifically, adult males with two segments fewer than adult females, for example, in the family Buotidae (males with 26, females with 28), in ''Xystrosoma beatense'' (males with 28, females with the usual 30), and in the family Peterjohnsiidae (males with the usual 30, females with 32). With these deviations from the usual 30 segments, the number of leg pairs in adults changes, usually with two leg pairs added or subtracted for each segment added to or subtracted from the typical number. For example, in ''Chamaesoma broelemanni'', with only 26 segments (four fewer than the typical number), adult females have only 42 leg pairs, and adult males have only 40 pairs of walking legs (excluding two pairs of gonopods). Adult females with 32 segments (two more than the typical number) have 54 leg pairs (e.g., in the family Peterjohnsiidae), which is the maximum number fixed by species in the class

Diplopoda 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 resu ...

. Many species deviate from the expected number of walking legs, however, because they deviate in terms of sex-linked modifications to their legs. For example, many species involve another leg pair in addition to pairs 8 and 9 in the gonopod complex in adult males. In the family Speophilosomatidae, leg pair 7 in adult males is modified as part of the gonopod complex. In many species, the gonopod complex instead includes leg pair 10 in addition to pairs 8 and 9 (e.g., '' Branneria carinata'', ''Reginaterreuma monroei,'' '' Golovatchia magda'', and ''Hoffmaneuma exiguum''). The family

Chordeumatidae Chordeumatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 7 mm to 18 mm in length and are found in Europe. Adult millipedes in this family have either 28 (e.g., ''Melagona scutellaris)'' or 30 (e.g. ...

exhibits the most extensive modifications, including five leg pairs (pairs 7 through 11) in the gonopod complex. Some species also deviate from the usual body plan by reducing or eliminating leg pairs in the adult female. In the family Chordeumatidae, for example, adult females feature a legless sternite (the "platosternite") where a third pair of legs would otherwise be. In other species (e.g., the genus ''Kashmireuma'' and the species ''Vieteuma longi''), adult females instead exhibit modifications to their second leg pair, which are reduced to small nubbins.

Distribution

Chordeumatidans have a large distribution, occurring on all continents except Antarctica. They are present in

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

but absent from

sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...

and, aside from southern

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, are largely absent from South America. They occur in the

tropics The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

, and

Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...

, and as far south as

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, and Chiloé Island, Chile. They are abundant in cold, rocky, mountainous areas of Europe and central Asia, and range northward to

Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

, and in North America up into Canada and southwest Alaska.

Classification

Chordeumatida contains approximately 1200 species, classified in four suborders and approximately 50

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

, although several families contain only one to five

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

. ;Suborder Chordeumatidea Pocock 1894 *Superfamily Chordeumatoidea C. L. Koch, 1847 **

C. L. Koch, 1847 ** Speophilosomatidae Takakuwa, 1949 ;Suborder Craspedosomatidea Cook, 1895 *Superfamily Anthroleucosomatoidea Verhoeff 1899 ** Anthroleucosomatidae Verhoeff 1899 **

Haasiidae Haasiidae is a family of millipedes belonging to the order Chordeumatida Chordeumatida (from the Greek word for "sausage") is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as "sausage ...

Hoffman, 1980 ** Origmatogonidae Verhoeff 1914 ** Vandeleumatidae Mauriès, 1970 *Superfamily Brannerioidea Cook, 1896 ** Brachychaeteumatidae Verhoeff, 1910 ** Branneriidae Cook, 1896 ** Chaemosomatidae Verhoeff, 1913 Atractosoma meridionale- Fauna Bavarica

Golovatchiidae Golovatchiidae is a family of millipedes belonging to the order Chordeumatida. This family contains a single species, ''Golovatchia magda''. This species ranges from 15 mm to 17 mm in length and is found in the Russian Far East. Adult millipedes o ...

Shear, 1992 ** Heterolatzeliidae Verhoeff 1899 ** Kashmireumatidae Mauriès, 1982 **

Macrochaeteumatidae Macrochaeteumatidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have only 28 segments (counting the collum as the first segment and the telson The telson () is the posterior-most division of ...

Verhoeff, 1914 ** Microlympiidae Shear & Leonard, 2003 ** Niponiosomatidae Verhoeff, 1941 ** Tingupidae Loomis, 1966 ** Trachygonidae Cook, 1896 *Superfamily Cleidogonoidea Cook, 1896 ** Biokoviellidae Mrsic, 1992 ** Cleidogonidae Cook, 1896 ** Entomobielziidae Verhoeff, 1899 ** Lusitaniosomatidae Schubart, 1953 ** Opisthocheiridae Ribaut, 1913 **

Trichopetalidae Trichopetalidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 28 or 30 segments (counting the collum as the first segment and the telson as the last). There are about 5 genera and at least 30 described ...

Verhoeff, 1914 *Superfamily Craspedosomatoidea Gray in Jones, 1843 **

Attemsiidae Attemsiidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 30 segments (counting the collum as the first segment and the telson The telson () is the posterior-most division of the body of ...

Verhoeff, 1899 Haasea flavescens Fauna Bavarica

** Craspedosomatidae Gray in Jones, 1843 **

Haplobainosomatidae Haplobainosomatidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 30 segments (counting the collum as the first segment and the telson The telson () is the posterior-most division of the ...

Verhoeff, 1909 *Superfamily Haaseoidea Attems, 1899 **

Haaseidae Haaseidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family range from 4.5 mm to 12 mm in length and have either 28 or 30 segments (counting the collum as the first segment and the telson as the last). ...

Attems, 1899 *Superfamily Neoatractosomatoidea Verhoeff, 1901 ** Altajellidae Mikhaljova & Golovatch, 2001 ** Cyrnosomatidae Mauriès, 2003 ** Faginidae Attems, 1926 ** Hoffmaneumatidae Golovatch, 1978 ** Mastigophorophyllidae Verhoeff, 1899 ** Neoactractosomatidae Verhoeff, 1901 *Superfamily Verhoeffioidea Verhoeff, 1899 ** Verhoeffiidae Verhoeff, 1899 ;Suborder Heterochordeumatidea Shear, 2000 *Superfamily Conotyloidea Cook, 1896 ** Adritylidae Shear, 1971 ** Conotylidae Cook, 1896 *Superfamily Diplomaragnoidea Attems, 1907 Schedotrigona

** Diplomaragnidae Attems, 1907 *Superfamily Heterochordeumatoidea Pocock, 1894 ** Eudigonidae Verhoeff, 1914 **

Heterochordeumatidae Heterochordeumatidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family have 30 or 32 segments (counting the collum as the first segment and the telson The telson () is the posterior-most division ...

Pocock, 1894 ** Megalotylidae Golovatch, 1978 ** Metopidiotrichidae Attems, 1907 ** Peterjohnsiidae Mauriès, 1987 *Superfamily Pygmaeosomatoidea Carl, 1941 ** Lankasomatidae Mauriès 1978 **

Pygmaeosomatidae Pygmaeosomatidae is a family of millipedes belonging to the order Chordeumatida Chordeumatida (from the Greek word for "sausage") is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as " ...

Carl, 1941 ;Suborder Striariidea Cook, 1896 *Superfamily Caseyoidea Verhoeff, 1909 ** Caseyidae Verhoeff, 1909 ** Urochordeumatidae Silvestri, 1909 *Superfamily Striarioidea Bollman, 1893 ** Apterouridae Loomis, 1966 ** Buotidae Shear, 2009 **

Rhiscosomididae ''Rhiscosomides'' is a genus of millipedes in the order Chordeumatida with seven described species, and is the only genus in the family Rhiscosomididae. Adult millipedes in this family have 30 segments (counting the collum as the first segme ...

Silvestri, 1909 **

Striariidae Striariidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 30 segments (counting the collum as the first segment and the telson The telson () is the posterior-most division of the body of an arthr ...

Bollman, 1893

References

External links

* * *
Chordeumatida of TasmaniaNorth American Chordeumatida
on BugGuide.net {{Taxonbar, from=Q4300743 Millipede orders