Pauropoda

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Pauropoda
Temporal range: 40–0  Ma
Eurypauropodid (12742282145) crop.jpg
A eurypauropod from New Zealand
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Pauropoda
Orders
Synonyms [1]
  • Heterognathes de Saussure & Humbert, 1872
  • Heterognatha Tömösváry, 1883
  • Monopoda Bollman, 1893

Pauropoda is a class of small, pale, millipede-like arthropods in the subphylum Myriapoda. More than 900 species in twelve families [2] [3] [4] are found worldwide, living in soil and leaf mold. Pauropods look like centipedes or millipedes and may be a sister group of the latter, [5] but a close relationship with Symphyla has also been posited. [6] [2] The name Pauropoda derives from the Greek pauros (meaning small or few) and pous or podus (meaning foot), because most species in this class have only nine pairs of legs as adults, a smaller number than those found among adults in any other class of myriapods. [7] [8] [9]

Contents

Anatomy and ecology

Ventral and dorsal views of Pauropus amicus from New South Wales, Australia. Pauropus amicus.jpg
Ventral and dorsal views of Pauropus amicus from New South Wales, Australia.

Pauropods are soft, cylindrical animals with bodies measuring only 0.3 to 2 mm in length. [8] [5] They have neither eyes nor hearts, although they do have sensory organs which can detect light. The body segments have ventral tracheal/spiracular pouches forming apodemes similar to those in millipedes and Symphyla, although the trachea usually connected to these structures are absent in most species. There are five pairs of long sensory hairs (trichobothria) located throughout the body segments. [10] Pauropods can usually be identified because of their distinctive anal plate, which is unique to pauropods. Different species of pauropods can be identified based on the size and shape of their anal plate. The antennae are branching, biramous, and segmented, which is distinctive for the group. [11] Pauropods are usually either white or brown.

Pauropods live in the soil, (usually at densities of less than 100 per square metre [9/sq ft]), and under debris and leaf litter. [11] [12] [13] [2]

Discovery

The first pauropod species to be discovered and described was Pauropus huxleyi , found in London in 1866 by Lord Avebury. [14] He wrote of the creature:

Pauropus huxleyi is a bustling, active, neat and cleanly creature. It has, too, a look of cheerful intelligence, which forms a great contrast to the dull stupidity of the Diplopods, or the melancholy ferocity of most Chilopods. [14] '

In 1870, Packard discovered a species of North American pauropod, extending the group's range. [15]

Evolution and systematics

Only one fossil species has been reported: Eopauropus balticus a prehistoric species of pauropod that was found in Baltic Amber. [2]

Pauropods are divided into two orders: Hexamerocerata and Tetramerocerata. Hexamerocerata contains only one family, Millotauropodidae, with a single genus and only eight species. [16] [17] Tetramerocerata is much larger and more diverse, with eleven families, including Pauropodidae, Brachypauropodidae, and Eurypauropodidae. [8] [18] The family Pauropodidae is especially large, with 27 genera and 814 species, [19] including most of the genera and species in the class Pauropoda. [4]

Adults in the order Tetramerocerata have a scarcely telescopic antennal stalk with four segments, six tergites, and eight to ten pairs of legs. [8] Pauropods in this order are small (sometimes quite small) and white or brownish. [20] Most species have nine pairs of legs as adults, [9] [21] but adults in four genera ( Cauvetauropus , Aletopauropus , Zygopauropus , and Amphipauropus) have only eight pairs of legs, [8] and adult females in the genus Decapauropus have either nine or ten pairs of legs. [17] The order Tetramerocerata has a subcosmopolitan distribution. [17]

Pauropods in the order Hexamerocerata have a strongly telescopic antennal stalk with six segments. [17] Adults in this order have twelve tergites and eleven pairs of legs. [8] The pauropods in this order are white and relatively long and large. [20] The order Hexamerocerata has a mainly tropical range. [8]

Reproduction and development

Pauropods, like all other myriapods, are gonochoric. [22] Male pauropods place small packets of sperm on the ground, which the females use to impregnate themselves. [2] The females then deposit the fertilized eggs on the ground. [23] Parthogenesis can occur in some species, especially when environmental conditions are unfavourable. [2] [24] [25]

The embryo goes through a short pupoid stage before the egg hatches and the first larval instar emerges. Juveniles then develop into adults through a series of molts, adding legs at each stage. Juveniles in the order Tetramerocerata start with three pairs of legs and progress through instars with five, then six, and then eight leg pairs, and in most species, become adults with nine leg pairs. In contrast, the first instar in the order Hexamerocerata has six leg pairs of legs and becomes an adult with eleven leg pairs. In at least some species in each order, adults continue to molt but no longer add legs or segments. [8] This mode of development is known as hemianamorphosis. [26]

Behavior and diet

Pauropods are shy of light, and will attempt to distance themselves from it. [27] Pauropods occasionally migrate upwards or downwards throughout the soil based on moisture levels. They feed on mold, fungi, and occasionally even the root hairs of plants. [13] Paurapods have a distinctive method of movement characterized by bursts of speed and frequent changes of direction. [2] As their bodies are too soft to be able to dig and burrow, pauropods follow roots and crevices in the soil, sometimes all the way down to the surface of the groundwater. [2] [23]

Related Research Articles

<span class="mw-page-title-main">Millipede</span> Class of arthropods

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.

<span class="mw-page-title-main">Symphyla</span> Class of many-legged arthropods

Symphylans, also known as garden centipedes or pseudocentipedes, are soil-dwelling arthropods of the class Symphyla in the subphylum Myriapoda. Symphylans resemble centipedes, but are very small, non-venomous, and only distantly related to both centipedes and millipedes. More than 200 species are known worldwide.

<span class="mw-page-title-main">Myriapoda</span> Subphylum of arthropods

Myriapods are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial.

<span class="mw-page-title-main">Pauropodidae</span> Family of many-legged arthropods

Pauropodidae is the most diverse family of pauropods, containing 27 genera and more than 800 species, as well as the only known fossil pauropod, Eopauropus. This family has a subcosmopolitan distribution. Pauropods in this family are generally whitish and feature a sternal antennal branch with one seta and one globulus, setae on the head and tergites that are usually tapering or cylindrical, and a single anal plate. Like most adult pauropods in the order Tetramerocerata, most adults in this family have 9 pairs of legs, but adults in one genus, Cauvetauropus, have only 8 pairs of legs, and female adults in another genus, Decapauropus, have either 9 or 10 pairs of legs. The first species found to include pauropods with more than 9 pairs of legs was D. cuenoti, first described with 10 pairs in 1931.

<span class="mw-page-title-main">Glomerida</span> Order of millipedes

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.

<span class="mw-page-title-main">Polyxenida</span> Order of millipedes

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.

Millotauropus is a genus of pauropods in the monotypic family Millotauropodidae in the monotypic order Hexamerocerata. The order Hexamerocerata includes only eight species and was created in 1950 to contain the newly discovered genus Millotauropus, which was found to have so many distinctive features as to warrant placement in a separate order. Before the discovery of Millotauropus, for example, pauropods were thought to have no more than ten leg pairs, but adults in the order Hexamerocerata have eleven pairs of legs.

Tetramerocerata is an order of pauropods containing 11 families and more than 900 species. This order was created in 1950 to distinguish these pauropods from those in the newly discovered genus Millotauropus, which was found to have such distinctive features as to warrant placement in a separate order (Hexamerocerata) created to contain that genus. The order Tetramerocerata includes the vast majority of pauropod species, as there are only eight species in the order Hexamerocerata, which remains the only other order in the class Pauropoda.

Eopauropus balticus is a prehistoric pauropod known from mid-Eocene Baltic amber. It is the only known pauropod in the fossil record. As pauropods are normally soil-dwelling, their presence in amber is unusual, and they are the rarest known animals in Baltic amber.

Brachypauropodidae is a family of pauropods. Pauropods in this family feature an entire first tergite, but at least the next three tergites are each divided into four to six sclerites, and the pygidial sternum has two or three pairs of setae. Like most adult pauropods in the order Tetramerocerata, most adults in this family have 9 pairs of legs, but adults in a few species in two genera, Aletopauropus and Zygopauropus, have only 8 pairs of legs. This family has a nearly worldwide distribution and is found on all continents except South America and Antarctica.

Linotaeniidae are a monophyletic clade of soil centipedes in the family Geophilidae found mostly in the temperate regions of the Holarctic as well as the south Andes. Species in the clade Linotaeniidae are characterized by a body that usually tapers toward the anterior tip; mandibles with a single pectinate lamella; second maxillae with coxo-sternite usually undivided and claws without projections; forcipular segment short, with tergite remarkably wide, forcipules evidently tapering; coxal organs opening through distinct pores on the ventral surface of the coxo-pleura. The number of legs in this clade varies within as well as among species and ranges from as few as 31 pairs of legs to as many as 83 leg pairs. Compared to most families in the suborder Adesmata, this clade features a modest number of leg-bearing segments and limited variation in this number within each species.

Caseyidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 30 segments. There are about 7 genera and at least 40 described species in Caseyidae.

<span class="mw-page-title-main">Cleidogonidae</span> Family of millipedes

Cleidogonidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 28, 29, or 30 segments. This family includes the genus Tianella, notable for featuring adult millipedes with 29 segments, a number not found in the adults of any other chordeumatidan species. Adults in most Tianella species have 29 segments, but adults in two have only 28 segments. In the Tianella species with 29 segments, adult females have 48 pairs of legs, as one would expect in adult female chordeumatidans with one segment fewer than the 30 usually found in this order. There are seven genera and at least 140 described species in Cleidogonidae.

<span class="mw-page-title-main">Conotylidae</span> Family of millipedes

Conotylidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 30 segments. There are about 19 genera and at least 60 described species in Conotylidae.

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.

<span class="mw-page-title-main">Striariidae</span> Family of millipedes

Striariidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 30 segments. There are at least 3 genera and about 13 described species in Striariidae.

Trichopetalidae is a family of millipedes in the order Chordeumatida. Adult millipedes in this family have 28 or 30 segments. There are about 5 genera and at least 30 described species in Trichopetalidae.

<span class="mw-page-title-main">Metopidiotrichidae</span> Family of millipedes

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.

Zygopauropus is a monotypic genus of pauropod in the family Brachypauropodidae. The only species in this genus is Zygopauropus hesperius, first described by J.W. MacSwain and U.N. Lanham of the University of California at Berkeley in 1948. This genus is notable as one of only four genera of pauropods in which adults have only eight pairs of legs rather than the nine leg pairs usually found in adults in the order Tetramerocerata. Before the discovery of Z. hesperius, adult pauropods were thought to have only nine or (rarely) ten pairs of legs.

Decapauropus is a large genus of pauropods in the family Pauropodidae that includes more than 300 species. This genus was originally described by Paul Remy in 1931 to contain the newly discovered type species Decapauropus cuenoti. As the name of this genus suggests, this genus is notable for including females with ten pairs of legs instead of the nine leg pairs usually found in adult pauropods in the order Tetramerocerata. Before the discovery of D. cuenoti, adult pauropods were thought to have invariably nine pairs of legs.

References

  1. ↑ Scheller, Ulf (2008). "A reclassification of the Pauropoda (Myriapoda)". International Journal of Myriapodology. 1 (1): 1–38. doi: 10.1163/187525408X316730 .
  2. 1 2 3 4 5 6 7 8 "Encyclopedia of Arkansas". Encyclopedia of Arkansas. Retrieved 2022-08-17.
  3. ↑ Minelli, Alessandro (2011). "Class Chilopoda, Class Symphyla and Class Pauropoda. In: Zhang, Z.-Q. (Ed.) Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness" (PDF). Zootaxa . 3148: 157–158. doi:10.11646/zootaxa.3148.1.31.
  4. 1 2 "ITIS - Report: Pauropoda". www.itis.gov. Retrieved 2024-02-28.
  5. 1 2 Cedric Gillott (2005). Entomology (3rd ed.). Springer. ISBN   978-1-4020-3182-3.
  6. ↑ Wang, Jiajia; Bai, Yu; Zhao, Haifeng; Mu, Ruinan; Dong, Yan (23 December 2021). "Reinvestigating the phylogeny of Myriapoda with more extensive taxon sampling and novel genetic perspective". PeerJ. 9: e12691. doi: 10.7717/peerj.12691 . ISSN   2167-8359. PMC   8710254 . PMID   35036164. S2CID   245468355.
  7. ↑ "Class Pauropoda | Terrestrial Mandibulates | The Diversity of Animal Life". biocyclopedia.com. Retrieved 2024-02-28.
  8. 1 2 3 4 5 6 7 8 Scheller, Ulf (2011). "Pauropoda". Treatise on Zoology - Anatomy, Taxonomy, Biology. The Myriapoda, Volume 1: 467–508. doi:10.1163/9789004188266_022. ISBN   9789004156111.
  9. 1 2 Snodgrass, R. E. (1952). Textbook of Arthropod Anatomy. Ithaca, NY: Cornell Univ. p. 250. ISBN   978-1-5017-4080-0. OCLC   1102791607.
  10. ↑ THE PAUROPODA - Savannah River Ecology Laboratory
  11. 1 2 David C. Coleman, D. A. Crossley, Jr. & Paul F. Hendrix (2004). Fundamentals of Soil Ecology (2nd ed.). Academic Press. p. 133. ISBN   978-0-12-179726-3.{{cite book}}: CS1 maint: multiple names: authors list (link)
  12. ↑ Alcocer, Yuanxin (Amy) Yang. "Pauropoda: Characteristics, Classification & Examples". study.com .
  13. 1 2 "pauropod | arthropod class | Britannica". www.britannica.com. Retrieved 2022-08-17.
  14. 1 2 British Museum (Natural History).; History), British Museum (Natural; Bell, F. J.; Calman, W. T.; Hirst, A. S. (1910). Guide to the Crustacea, Arachnida, Onychophora and Myriopoda exhibited in the Department of Zoology, British Museum (Natural History) ... London: Printed by order of the Trustees.
  15. ↑ Entomological Society of Washington; Washington, Entomological Society of (1943). Proceedings of the Entomological Society of Washington. Vol. 45. Washington, etc: Entomological Society of Washington.
  16. ↑ "ITIS - Report: Hexamerocerata". www.itis.gov. Retrieved 2024-02-28.
  17. 1 2 3 4 Scheller, Ulf (2008-01-01). "A reclassification of the Pauropoda (Myriapoda)". International Journal of Myriapodology. 1 (1): 1–38. doi: 10.1163/187525408X316730 . ISSN   1875-2535.
  18. ↑ "ITIS - Report: Tetramerocerata". www.itis.gov. Retrieved 2024-02-28.
  19. ↑ "ITIS - Report: Pauropodidae". www.itis.gov. Retrieved 2024-02-28.
  20. 1 2 Sadler, Pamela (2022-01-06). "Pauropods - Reproductive Biology". GUWS Medical. Retrieved 2022-08-17.
  21. ↑ Peter Ax (2000). "Pauropoda". Multicellular Animals: The phylogenetic system of the Metazoa. Volume 2 of Multicellular Animals: A New Approach to the Phylogenetic Order in Nature. Springer. pp. 231–233. ISBN   978-3-540-67406-1.
  22. ↑ Krishna (2020-10-28). "Myriapods: their Characteristics, Anatomy, Habitat, Diet, and Reproduction". ckrokill. Retrieved 2022-08-17.
  23. 1 2 "Class Pauropoda". keys.lucidcentral.org. Retrieved 2022-08-18.
  24. ↑ "Pauropods: Pauropoda | Encyclopedia.com". www.encyclopedia.com. Retrieved 2022-08-17.
  25. ↑ "Parthenogenesis - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-08-17.
  26. ↑ Fusco, Giuseppe (December 2005). "Trunk segment numbers and sequential segmentation in myriapods". Evolution & Development. 7 (6): 608–617. doi:10.1111/j.1525-142X.2005.05064.x. PMID   16336414. S2CID   21401688 . Retrieved 25 August 2020.
  27. ↑ Minelli, Alessandro (2011). The Myriapoda - Treatise on Zoology - Anatomy, Taxonomy, Biology. Brill Publishers. p. 495. ISBN   978-90-04-15611-1.

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