Prosopodesmus panporus | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Myriapoda |
Class: | Diplopoda |
Order: | Polydesmida |
Family: | Haplodesmidae |
Genus: | Prosopodesmus |
Species: | P. panporus |
Binomial name | |
Prosopodesmus panporus Blower & Rundle, 1980 | |
Prosopodesmus panporus is a species of flat-backed millipede in the family Haplodesmidae. [1] Also known as the hothouse millipede, [2] this species was first discovered in hothouses for tropical plants in England, [3] where it is well established, [4] but is probably native to Australia. [5] This species features a unique distribution of ozopores, which appear on all segments with two pairs of legs. The species P. panporus is named for this complete series of ozopores and is the only species in the order Polydesmida with this distribution. [4] This millipede is also notable for exhibiting sexual dimorphism in segment number: Whereas adult females of this species feature the 20 segments usually observed in the order Polydesmida (counting the collum as the first segment and the telson as the last), the adult males of this species feature only 19 segments. [6]
This species was first described in 1980 by the British myriapodologist John Gordon Blower and Adrian J. Rundle. [7] They based the original description of this species on several specimens collected by Rundle from four hothouses in Kew Gardens in England. [3] [7] Rundle found these specimens in 1975 and 1976 in the course of a survey of the fauna of Kew Gardens. The type specimens include a male holotype and several paratypes, including both sexes and multiple juveniles as well as adults. The holotype and most of the paratypes are deposited in the Natural History Museum in London. [7]
Blower and Rundle inferred that this species had been introduced from some tropical habitat overseas. [7] The geographic origin of this species, however, remained a mystery until 2012, when the zoologist Robert Mesibov reported the discovery of P. panporus specimens in a remote tropical rainforest in Australia. These specimens include 24 males and five females collected in 1986 from rainforest litter on the Cape York penninsula of Queensland in Australia. Both the remote location of this site and the discovery of other Prosopodesmus species in the tropical rainforests of north Queensland indicate that P. panporus is native to Queensland. [3]
This millipede is cream white with almost no pigment. The head is nearly completely covered by the collum, which is shaped like a fan. The gonopods are simple and end with several prominent teeth on the lateral edge, one apical and four or five near the tip. This species is among the smallest millipedes known: The adult males range from 3.3 to 3.8 mm in length and from 0.45 to 0.50 mm in breadth; the adult females range from 3.8 to 4.3 mm in length and from 0.50 to 0.51 mm in breadth. [7]
Adult females of this species have the 20 segments (including the telson) typically observed among flat-backed millipedes, but adult males feature only 19 segments. [6] Blower and Rundle studied a sample of juveniles including all stages of post-embryonic development and found that this species goes through the same stages of teloanamorphosis usually observed in the order Polydesmida, except males mature and stop molting one stage earlier. [7] Thus, whereas females emerge as adults in the eighth stage with the usual 20 segments and 31 pairs of legs, the males emerge as adults in the seventh stage with only 19 segments and 28 leg pairs (excluding the eighth pair, which become gonopods). [4] [6]
The dorsal surface of each segment is paved with tubercles. The collum features five rows of tubercles, but the other segments each feature three rows of tubercles on strongly arched tergites. The telson also has three rows of tubercles, with twelve tubercles overhanging the posterior edge of the telson as six lobes on each side. [7]
This species features a unique distribution of ozopores, which appear on each segment with two leg pairs. Thus, adult females have ozopores on segments 5 through 18, and adult males have ozopores on segments 5 through 17. The legless penultimate segment in front of the telson (segment 19 in adult females, segment 18 in adult males) also features a rudimentary pair of ozopores. Each pair of ozopores appears on the outermost pair of tubercles, in the second row of the fifth segment and in the third row of the other segments. [7]
This millipede shares many features with other Prosopodesmus species, including the general form of the body, the fan-shaped collum covering the head from above, three rows of tubercles on the dorsal surface of the segments, and simple gonopods. [7] [8] This species may be distinguished from its close relatives, however, by its unique series of ozopores and the number of segments in adult males. For example, although P. panporus resembles the Prosopodesmus type species P. jacobsoni in many respects, the type species features 20 segments in both sexes. Furthermore, although P. jacobsoni also features an unusually extensive series of ozopores (on segment 5 and segments 7 through 19), P. panporus also features ozopores on segment 6 and merely rudimentary ozopores on the legless penultimate segment. [7] [9]
The species P. jacobsoni also differs from P. panporus in other respects. For example, P. jacobsoni is larger (6.0 mm long and 0.71 mm wide), is red-brown rather than cream white, and has ten lobes rather than twelve on the posterior edge of the telson. Moreover, the gonopods of P. jacobsoni feature not only a large lateral lamella that is absent in P. panporus but also only two teeth near the tip where P. panporus features four or five teeth. Finally, where the three rows of tubercles feature tubercles of equal size in P. panporus, the first row has the largest tubercles and the third row the smallest tubercles in P. jacobsoni. [7]
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.
Polyzoniida is an order of millipedes in the subterclass Colobognatha. This order contains three families and more than 70 described species. The species in this order are also known as camphor millipedes, because ozopore secretions in this order frequently have a strong camphor-like smell. Poison frogs in South America and Madagascar evidently obtain some of their poison from these millipedes.
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.
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.
Metopidiotrichidae is a family of millipedes in the order Chordeumatida. This family includes more than 70 species. These millipedes are found in Indochina, Australia, and on Pacific islands from New Zealand to Japan.
Brachydesmus is a genus of millipedes belonging to the family Polydesmidae. The Czech zoologist Camill Heller first described this genus to contain the type species B. subterraneus. This genus now includes about 75 described species.
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 or 30 segments. This family features distinctive sex-linked modifications to the legs in adults: In the adult female, a legless sternite replaces the third pair of legs, and in the adult male, five pairs of legs are modified in the gonopod complex. These modifications are more extensive than those found in other adult males in this order, which often have only two leg pairs modified into gonopods. With the more extensive modifications to the legs in this family, species with the usual 30 segments feature adult females with only 49 leg pairs and adult males with only 45 pairs of walking legs, and species with only 28 segments feature adult females with only 45 leg pairs and adult males with only 41 pairs of walking legs.
Speophilosomatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes are found in Japan and range from 4 mm to 6 mm in length. Adult millipedes in this family are notable for being among the few in this order with only 26 segments instead of the 30 usually found in chordeumatidans. The adult males in this family are also notable for involving three leg pairs in the gonopod complex rather than the two pairs typically modified into gonopods in this order.
Peterjohnsiidae is a small family of millipedes belonging to the order Chordeumatida. The family was first described in 1987 by Jean-Paul Mauriès. These millipedes range from 3 mm to 8 mm in length and are found in Australia. Species in this family exhibit sexual dimorphism in segment number: adult males have 30 segments, but adult females have 32 segments. In adult males in this family, the gonopod complex involves three leg pairs rather than just the two usually modified into gonopods in this order.
Hoffmaneumatidae is a family of millipedes belonging to the order Chordeumatida. This family includes two genera, one (Hoffmaneuma) found in the Russian Far East and the other (Japanoparvus) found in Japan. Millipedes in this family range from 4 mm to 6 mm in length. Adult millipedes in this family have only 28 segments, not the 30 segments usually found in this order. Adult males in this family feature a reduced leg pair 10 in addition to the two pairs normally modified into gonopods in this order. In the adult male of the species Hoffmaneuma exiguum, for example, the gonopod complex derives from all three leg pairs rather than from just the usual two.
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.
Devillea is a genus of flat-backed millipedes in the family Xystodesmidae. These millipedes are rare and limited to caves. Species in this genus are found in Sardinia, Capri, and southern France in the Maritime Alps. These species are notable for featuring more than the 20 segments usually found in the order Polydesmida. This genus is one of only two genera in this order to feature these extra segments and the first such genus to be discovered.
Lipseuma is a genus of millipedes in the family Kashmireumatidae. This genus contains only two species, the type species L. josianae and its close relative L. bernardi. Both species are troglobites found in caves in China.
Metamastigophorophyllon is a genus of millipedes in the family Anthroleucosomatidae. This genus includes millipedes found in Azerbaijan, Iran, Russia, and Georgia. All five species in this genus have 31 segments in adults. This genus is notable for including the only species in the order Chordeumatida with 31 segments rather than the 30 segments usually observed in adults in this order.
Neocambrisoma is a genus of millipedes in the family Metopidiotrichidae. Millipedes in this genus are found in Tasmania and New South Wales in Australia. Like other genera in this family, this genus features 32 segments in adults of both sexes, rather than the 30 segments usually observed in adults in the order Chordeumatida. Accordingly, female adults in this genus have 54 pairs of legs, which is not only the maximum number observed in this order but also the maximum number fixed by species in the class Diplopoda.
Devilliea tuberculata is a species of flat-backed millipedes in the family Xystodesmidae. Like other members of the genus Devillea, this species is limited to caves. This millipede has been found in several caves in the Alpes-Maritimes department of France. This species is notable as the first millipede in the order Polydesmida found to feature more than the 20 segments usually found in this order.
Neocambrisoma raveni is a species of millipede in the family Metopidiotrichidae. These millipedes are found in New South Wales in Australia. Like other species in this family, N. raveni features 32 segments in adults of both sexes, rather than the 30 segments usually observed in adults in the order Chordeumatida. Accordingly, adult females of this species have 54 pairs of legs, which is not only the maximum number observed in this order but also the maximum number fixed by species in the class Diplopoda.
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.
Prosopodesmus is a genus of flat-backed millipedes in the family Haplodesmidae. These millipedes are found primarily in Australia and southern Japan. This genus includes the species P. panporus, which is notable for exhibiting sexual dimorphism in segment number: Whereas adult females of this species feature the usual 20 segments usually observed in the order Polydesmida, the adult males of this species feature only 19 segments.