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

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. [2]

Discovery

The first pauropod species to be discovered and described was Pauropus huxleyi , found by Lord Avebury in his own garden in London in 1866. [12] [13] 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. [12] '

In 1870, Packard discovered a species of North American pauropod, extending the group's range. [14]

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. [15] [16] Tetramerocerata is much larger and more diverse, with eleven families, including Pauropodidae, Brachypauropodidae, and Eurypauropodidae. [8] [17] The family Pauropodidae is especially large, with 27 genera and 814 species, [18] 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, five or six tergites, and eight to ten pairs of legs. [8] Pauropods in this order are small (sometimes quite small) and white or brownish. [19] Most species have nine pairs of legs as adults, [9] [20] 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. [16] The order Tetramerocerata has a subcosmopolitan distribution. [16]

Pauropods in the order Hexamerocerata have a strongly telescopic antennal stalk with six segments. [16] 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. [19] The order Hexamerocerata has a mainly tropical range. [8]

Reproduction and development

Pauropods, like all other myriapods, are gonochoric. [21] 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. [22] Parthogenesis can occur in some species, especially when environmental conditions are unfavourable. [2] [23] [24]

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. [25]

Behavior and diet

Paurapods have a distinctive method of movement characterized by bursts of speed and frequent changes of direction. [2] Pauropods are shy of light and will attempt to distance themselves from it. [26] 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] [27] [28] [2] 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. [28] 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] [22]

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">Centipede</span> Many-legged arthropods with elongated bodies

Centipedes are predatory arthropods belonging to the class Chilopoda of the subphylum Myriapoda, an arthropod group which includes millipedes and other multi-legged animals. Centipedes are elongated segmented (metameric) creatures with one pair of legs per body segment. All centipedes are venomous and can inflict painful stings, injecting their venom through pincer-like appendages known as forcipules or toxicognaths, which are actually modified legs instead of fangs. Despite the name, no species of centipede has exactly 100 legs; the number of pairs of legs is an odd number that ranges from 15 pairs to 191 pairs.

<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. This family has a subcosmopolitan distribution. These pauropods usually live in the soil on mountains and hills. This family also includes the only known fossil pauropod (Eopauropus).

<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. These features have inspired the common names bristly millipedes or pincushion millipedes. This order includes about 148 species in four families worldwide, which represent 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. This family has a nearly worldwide distribution. Pauropods in this family are 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.

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

Siphonotidae is a family of millipedes in the order Polyzoniida. This family includes more than 70 species distributed among 13 genera. These millipedes are found in South America, South Africa, Madagascar, Southeast Asia, and New Zealand. Millipedes in this family have a narrow telson and are quick and active.

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">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.

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.

Zygopauropus is a monotypic genus of pauropod in the family Brachypauropodidae. The only species in this genus is Zygopauropus hesperius, which is found in the western United States. 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 Zygopauropus, 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 the French zoologist 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.

Decapauropus cuenoti is a species of pauropod in the family Pauropodidae. As the name of the genus Decapauropus suggests, this species 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 9 "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. JSTOR   10.7591/j.ctvn1tb6g. 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. 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.
  13. ↑ Pauropoda (Myriapoda), a class new to the Dutch fauna, with the description of a new species
  14. ↑ Entomological Society of Washington; Washington, Entomological Society of (1943). Proceedings of the Entomological Society of Washington. Vol. 45. Washington, etc: Entomological Society of Washington.
  15. ↑ "ITIS - Report: Hexamerocerata". www.itis.gov. Retrieved 2024-02-28.
  16. 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.
  17. ↑ "ITIS - Report: Tetramerocerata". www.itis.gov. Retrieved 2024-02-28.
  18. ↑ "ITIS - Report: Pauropodidae". www.itis.gov. Retrieved 2024-02-28.
  19. 1 2 Sadler, Pamela (2022-01-06). "Pauropods - Reproductive Biology". GUWS Medical. Retrieved 2022-08-17.
  20. ↑ 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.
  21. ↑ Krishna (2020-10-28). "Myriapods: their Characteristics, Anatomy, Habitat, Diet, and Reproduction". ckrokill. Retrieved 2022-08-17.
  22. 1 2 "Class Pauropoda". keys.lucidcentral.org. Retrieved 2022-08-18.
  23. ↑ "Pauropods: Pauropoda | Encyclopedia.com". www.encyclopedia.com. Retrieved 2022-08-17.
  24. ↑ "Parthenogenesis - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-08-17.
  25. ↑ 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.
  26. ↑ Minelli, Alessandro (2011). The Myriapoda - Treatise on Zoology - Anatomy, Taxonomy, Biology. Brill Publishers. p. 495. ISBN   978-90-04-15611-1.
  27. ↑ Alcocer, Yuanxin (Amy) Yang. "Pauropoda: Characteristics, Classification & Examples". study.com .
  28. 1 2 "pauropod | arthropod class | Britannica". www.britannica.com. Retrieved 2022-08-17.

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