| Platyrhacidae | |
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| Nyssodesmus python from Central America | |
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| Family: | Platyrhacidae Pocock, 1895 |
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c. 50 [1] | |
| Synonyms | |
Platyrrhacidae | |
Platyrhacidae is a family of polydesmidan millipedes distributed in Southeast Asia and tropical Central and South America.
Platyrhacids are often large and colorful. They can be distinguished from most other polydesmidans by having ozopores situated further inward from the paranota margins, ozopores surrounded by a broad, flat ring, and presence of compound setae on the labrum and often on the epiproct (a posterior extension of the telson). The gonopods in males are relatively simple, although up to five gonopodal processes ("branches") may be present in some genera from Borneo. [2] [3] Large platyrhacids in Borneo may grow up to 13 cm (5.1 in) long and exhibit colors of blue, green, and yellow with black spots or stripes. [4] The largest known species in the order Polydesmida, however, is a platyrhacid species found in Sumatra, Gigantorhacus mirandus, which can reach 134 mm (5.3 in) in length. [5]
Platyrhacids occur in two disjunct geographic areas. The majority of species occur in Southeast Asia, including the Greater Sunda Islands and the Philippine archipelago. The rest occur in the New World Tropics from Nicaragua to Peru, as well as on some Caribbean islands. [3] [6]
The Platyrhacidae is part of the larger suborder Chelodesmidea. The family Platyrhacidae is subdivided into several groups, formerly considered tribes but elevated to the status of subfamilies in 2013. [6]
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The following genera have not yet been placed into a subfamily [6]
The family (originally misspelled "Platyrrhacidae") was named by Reginald Pocock in 1895 to include the single genus Platyrhacus . Shortly after, Orator F. Cook added Acanthodesmus , Odontodesmus , and Trachelodesmus . By 1897, additional works by Cook, Pocock, and Filippo Silvestri had increased the number of genera to 37.
The North American genera Euryurus , Auturus , and Illiniurus , were long-considered to constitute a sub-group of Platyrhacidae (i.e. the subfamily Euryurinae or tribe Euryurini in various classifications), until separated as a distinct family (Euryuridae) by Hoffman in 1998 and allied closer to Xystodesmidae. Similarly and concurrently, several neotropical genera previously placed in other subgroups of Platyrhacidae were removed and elevated to full family status: the Aphelidesmidae. [2]
Chilognatha is a subclass of the class Diplopoda, which includes the vast majority of extant millipedes, about 12,000 species.
Harpaphe haydeniana, commonly known as the yellow-spotted millipede, almond-scented millipede or cyanide millipede, is a species of polydesmidan ("flat-backed") millipede found in the moist forests along the Pacific coast of North America, from Southeast Alaska to California. The dark coloration with contrasting yellow-tipped keels warn of its ability to exude toxic hydrogen cyanide as a defense. The cyanide secretions are not dangerous to humans, but can cause irritation and pain if it contacts sensitive areas such as the mouth, eyes, or nose.
Polydesmida is the largest order of millipedes, with more than 5,000 species, including all the millipedes reported to produce hydrogen cyanide (HCN). This order is also the most diverse of the millipede orders in terms of morphology. Millipedes in this order are found in all regions of the world other than Antarctica.
Xystodesmidae is a family of millipedes in the suborder Leptodesmidea within the order Polydesmida. The family Xystodesmidae was created by the American biologist Orator F. Cook in 1895 and named after the genus Xystodesmus. This family includes more than 390 known species distributed among 62 genera. Many species, however, remain undescribed: 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.
Paradoxosomatidae, the only family in the suborder Paradoxosomatidea, is a family of flat-backed millipedes in the order Polydesmida. Containing nearly 200 genera and 975 species as of 2013, it is one of the largest families of millipedes. Paradoxosomatids occur on all continents except Antarctica, and can generally be distinguished by dorsal grooves on most body segments and a dumb-bell shaped gonopod aperture. Notable groups within the Paradoxosomatidae include the dragon millipedes of Southeast Asia, and the widely introduced greenhouse millipede Oxidus gracilis.
Richard Lawrence Hoffman was an American zoologist known as an international expert on millipedes, and a leading authority on the natural history of Virginia and the Appalachian Mountains. He was a biology professor at Virginia's Radford College for almost thirty years, and curator of invertebrates at the Virginia Museum of Natural History for another twenty years. He co-founded the Virginia Natural History Society, described over 400 species of millipedes, and produced more than 480 scientific publications. He is commemorated in the scientific and/or common names of over 30 animal species, including the valley and ridge salamander and Hoffman's dwarf centipede.
Chordeumatida is a large order of millipedes containing more than 1,400 species. Also known as sausage millipedes, they are found nearly worldwide. Chordeumatida is the largest order in the superorder Nematophora, a group also known as spinning millipedes because their telsons feature spinnerets used to build nests of silk. These millipedes produce this silk to create chambers in which to molt or to lay their 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.
Harold Frederick Loomis was an American botanist and myriapodologist known for his contributions to agronomy, plant pathology, and millipede taxonomy. He worked for the U.S. Department of Agriculture for over four decades, studying diseases of crop plants, and was a colleague of Orator F. Cook. He also made major contributions to the natural history of Central America and the West Indies, naming over 500 species of millipedes in total. He co-described with Cook the leggiest animal on earth: Illacme plenipes, with over 700 legs.
Orthomorpha coarctata, the long-flange millipede, is a widely introduced species of Polydesmidan millipede of the family Paradoxosomatidae. It is presumed native to Southeast Asia but due to transport by humans occurs in tropical and sub-tropical areas throughout the world, including the Hawaiian Islands, the West Indies, Gulf Coast of North America, and the Galápagos Islands.
Casimir Albrecht Willem Jeekel (1922–2010) was a Dutch myriapodologist and entomologist known for his major contributions to the taxonomy of millipedes. His 1971 monograph Nomenclator Generum et Familiarum Diplopodorum is credited as launching the "modern era" of millipede taxonomy, and has been considered the "most important single work ever published on the Diplopoda". He served as director of the Zoological Museum Amsterdam, and authored over 150 works on the taxonomy of millipedes and other myriapods.
Psammodesmus is a genus of platyrhacid millipedes found from Panama to Peru. The 11 species constitute the platyrhacid subfamily Psammodesminae.
Haplodesmidae is a family of millipedes in the order Polydesmida. This family includes about 70 species. Species occur in East Asia, Southeast Asia, and Oceania, although some species have been introduced to the New world tropics.
Ammodesmidae is a family of small millipedes endemic to Africa, containing seven species in two genera. Ammodesmids range from 1.4 to 5.0 mm long with 18 or 19 body segments in both sexes, and are capable of rolling into a tight sphere.
Fuhrmannodesmidae is a family of millipedes belonging to the order Polydesmida. Although some authorities deem Fuhrmannodesmidae to be a junior synonym for Trichopolydesmidae, others still regard the taxonomic status of Fuhrmannodesmidae as valid. The family Fuhrmannodesmidae includes over 50 genera.
Sphaeriodesmidae is a family of flat-backed millipedes in the order Polydesmida. There are about 15 genera and at least 90 described species in Sphaeriodesmidae.
Rhachodesmidae is a family of flat-backed millipedes in the order Polydesmida. There are more than 20 genera and at least 80 described species in Rhachodesmidae.
Stenoniodes, commonly known as the Borneo tractor millipede, is a genus of millipede in the family Platyrhacidae. It contains six species, five of which occur on Borneo and one on Sibutu Island. Its common name originates from the likeness of its 20-segmented body to the tread of a tractor's tire.
Agenodesmus is a genus of millipedes in the family Fuhrmannodesmidae, which some authorities consider a junior synonym of Trichopolydesmidae. This genus is notable for being among the very few genera in the order Polydesmida to feature adults with only 18 segments rather than the 20 segments usually found in this order. The genus Agenodesmus contains only two species, A. reticulatus and A. nullus. The type species A. reticulatus is notable as the first polydesmidan millipede discovered with only 18 segments in adults, the smallest number recorded in the order Polydesmida. Before the discovery of A. reticulatus, polydesmidans were known to have only 19 or 20 segments in adults.
Agenodesmus reticulatus is a species of millipede in the family Fuhrmannodesmidae, which some authorities consider a junior synonym of Trichopolydesmidae. This millipede is among the very few species in the order Polydesmida to feature adults with only 18 segments rather than the 20 segments usually found in this order. This species is notable as the first polydesmidan millipede discovered with only 18 segments in adults, the smallest number recorded in the order Polydesmida. Before the discovery of A. reticulatus, polydesmidans were known to have only 19 or 20 segments in adults.
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