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Symphyla

From Wikipedia, the free encyclopedia
Not to be confused withSymphyta.

Symphyla
Temporal range:99–0MaMidCretaceoustoPresent
Scutigerellasp. (Scutigerellidae)
Scollopendrellid symphylan (Scolopendrellidae)
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Symphyla
Ryder,1880
Families

Scutigerellidae
Scolopendrellidae

Symphylans,also known asgarden centipedesorpseudocentipedes,are soil-dwellingarthropodsof theclassSymphylain the subphylumMyriapoda.Symphylans resemblecentipedes,but are very small, non-venomous, and only distantly related to both centipedes andmillipedes.[1][2]More than 200 species are known worldwide.[3]

Symphyla are primarilyherbivoresanddetritusfeeders living deep in the soil, under stones, in decaying wood, and in other moist places.[4]They are rapid runners,[4]can move quickly through the pores between soil particles, and are typically found from the surface down to a depth of about 50 centimetres (20 in). Theyconsume decaying vegetation,but can do considerable harm in anagriculturalsetting by consuming seeds, roots, and root hairs in cultivated soil.[1][2]For example, the garden symphylan,Scutigerella immaculatacan be a pest of crops. A species ofHanseniellahas been recorded as a pest ofsugar caneandpineapplesinQueensland.[5][6]A few species are found in trees[7][8]and in caves.[9]A species ofSymphylellahas been shown to be predominantly predatory,[10]and some species aresaprophagous.

Description[edit]

Several individuals ofScutigerellasp., showing their small size

Symphyla are small,crypticmyriapods without eyes and withoutpigment.[4]The body is soft and generally 2 to 10 millimetres (0.08 to 0.4 in) long, divided into two body regions: head and trunk.[4]An exceptional size is reached inHanseniella magna,which attains lengths of 12-13 mm (0.5 in).[11]

The head has long, segmentedantennae,a postantennal organ, three pairs ofmouthparts:mandibles,the long first maxillae, and the second pair of maxillae which are fused to form the lower lip or labium of the mouth. The antennae serve as sense organs. Disc-likeorgans of Tömösváry,which probably sense vibrations, are attached to the base of the antennae, as they are in centipedes.[2]

The trunk comprises 15–24 segments, which are protected by overlapping dorsal plates. Ten or twelve segments bearlegs.The first segment is large and usually provided with a pair of legs, the last segment is slender, lacks legs, and possesses a pair ofcerci.Symphylans have been reported as living up to four years, andmoultthroughout their life.[2]Immature individuals have six pairs of legs on hatching, but they add an additional pair at eachmoultuntil the adultinstar,which usually has twelve pairs of legs.[12][13]This mode of development is known ashemianamorphosis.[14]Although most adult symphylans have twelve leg pairs, the first pair is absent or vestigial in some species (e.g., those in the genusSymphylella), so adults in some species have only eleven leg pairs.[15][16]

Symphylans have several features linking them to early insects, such as a labium (fused second maxillae), an identical number of head segments and certain features of their legs.[1]Each pair of legs is associated with an eversible structure, called a "coxal sac", that helps the animal absorb moisture, and a small stylus that may be sensory in function. Similar structures are found in the most primitive insects.

Life stages of symphylans: eggs, juvenile, and adultScutigerella immaculata

Symphylans breathe through a pair ofspiracleson the sides of their head, and are the only arthropods with spiracle openings on the head.[17]These are connected to a system oftracheaethat branch through the head and the first three segments of the body only.[2]

The genital openings are located on the fourth body segment, but the animals do not copulate. Instead, the male deposits 150 to 450 packages of sperm, orspermatophores,on small stalks. The female then picks these up in her mouth, which contains special pouches for storing the sperm. She then lays her eggs, and attaches them to the sides of crevices or to moss or lichen with her mouth, smearing the sperm over them as she does so. The eggs are laid in groups of eight to twelve.[2]

Symphylans also havespinneretswhose secretions turn into a silk-like thread.[18]One fossil species,Symphylella patrickmuelleri,was found preserved inBurmese Amberreleasing long threads of silk.[19]The silk plays a role in reproduction: the male deposits up to 450 spermatophores on stalks of silk.[20]Symphylans have also been reported releasing silk as a defense[21]and to suspend themselves in the air.[2]

Fossil record and evolution[edit]

The symphylan fossil record is poorly known, with only five species recorded, all placed in living genera. The oldest records of both families are found inBurmese amberfrom the middleCretaceous,approximately 99 million years ago. As a result, both families are thought to have diverged before the end of the Mesozoic Era.[22][23][24]

Despite their common name, morphological studies commonly place symphylans as more closely related tomillipedesandpauropodsthan thecentipedes,in the cladeProgoneata.[25][26]Molecular studieshave shown conflicting results, with some supporting the Progoneata clade, others aligning symphylans with centipedes or other arthropods, although some are weakly supported.[27][25]The clade is believed to bemonophyletic.[28]

References[edit]

  1. ^abcC. Gillott (2005).Entomology, 3rd Edition.Springer Verlag.ISBN978-1-4020-3182-3.
  2. ^abcdefgBarnes, Robert D. (1982).Invertebrate Zoology.Philadelphia, PA: Holt-Saunders International. pp. 817–818.ISBN978-0-03-056747-6.
  3. ^"ITIS - Report: Symphyla".www.itis.gov.Retrieved2024-02-28.
  4. ^abcdPenny Greenslade (2002-03-31)."Class: Symphyla".Australian Faunal Directory.Australian National University.Archived fromthe originalon 2015-09-24.
  5. ^H. Boyle (1981). "Symphyla control in young plant cane".Cane Growers' Quarterly Bulletin.44:115–116.
  6. ^D. A. H. Murray & D. Smith (1983). "Effect of Symphyla,Hanseniellasp., on establishment of pineappes in south-east Queensland ".Queensland Journal of Agricultural Science.40:121–123.
  7. ^J. Adis & U. Scheller (1984)."On the natural history and ecology ofHanseniella arborea(Myriapoda, Symphyla, Scutigerellidae), a migrating symphylan from an Amazonian black-water inundation forest ".Pedobiologia.27:35–41.doi:10.1016/S0031-4056(23)05818-3.S2CID89444581.
  8. ^S. Clark & P. Greenslade (1996). "Review of TasmanianHanseniellaBagnall (Symphyla: Scutigerellidae) ".Invertebrate Taxonomy.10(1): 189–212.doi:10.1071/IT9960189.
  9. ^Eberhard, S.M. & Spate (1995). "Cave Invertebrate Survey; toward an atlas of NSW Cave Fauna".A Report Prepared Under NSW Heritage Assistance Program NEP.94:765.
  10. ^D. E. Walter, J. C. Moore & S. Loring (1989). "Symphylellasp. (Symphyla: Scolopendrellidae predators of arthropods and nematodes in grassland soils ".Pedobiologia.33:113–116.
  11. ^Scheller, U. (1996)https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1440-6055.1996.tb01391.x
  12. ^"Garden Symphylans".Integrated Pest Management on Peppermint-IPMP3.0.Oregon State University.Archived fromthe originalon 2007-08-03.Retrieved2007-07-02.
  13. ^"Symphylans".Entry: Symphylans.Encyclopedia of Arkansas.Retrieved2021-05-29.
  14. ^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.PMID16336414.S2CID21401688.Retrieved25 August2020.
  15. ^Szucsich, Nikola; Scheller, Ulf (2011). "Symphyla". In Minelli, Alessandro (ed.).The Myriapoda. Volume 1.Leiden: Brill. pp. 445–466.ISBN978-90-04-18826-6.OCLC812207443.
  16. ^Minelli, Alessandro; Golovatch, Sergei I. (2013-01-01),"Myriapods",in Levin, Simon A (ed.),Encyclopedia of Biodiversity (Second Edition),Waltham: Academic Press, pp. 421–432,doi:10.1016/b978-0-12-384719-5.00208-2,ISBN978-0-12-384720-1,retrieved2022-02-28
  17. ^BIOLOGICAL SCIENCE FUNDAMENTALS AND SYSTEMATICS - Volum III
  18. ^"X: The Symphyla"(PDF).Arthropod Anatomy.JSTOR10.7591/j.ctvn1tb6g.14.
  19. ^Moritz, Leif; Wesener, Thomas (2018-04-01)."Symphylella patrickmuelleri sp. nov. (Myriapoda: Symphyla): The oldest known Symphyla and first fossil record of Scolopendrellidae from Cretaceous Burmese amber".Cretaceous Research.84:258–263.Bibcode:2018CrRes..84..258M.doi:10.1016/j.cretres.2017.11.018.ISSN0195-6671.
  20. ^"Symphylans".Encyclopedia of Arkansas.Retrieved2023-05-02.For reproduction, males do not copulate with the female. Rather, they deposit 150 to 450 sperm packets (spermatophores) on top of short stalks of silk on the ground.
  21. ^Schulze, L. (Jan 1975),Structure, composition and properties of spun products
  22. ^Moritz, Leif; Wesener, Thomas (2017). "Symphylella patrickmuellerisp. nov. (Myriapoda: Symphyla): The oldest known Symphyla and first fossil record of Scolopendrellidae from Cretaceous Burmese amber ".Cretaceous Research.84:258–263.Bibcode:2018CrRes..84..258M.doi:10.1016/j.cretres.2017.11.018.
  23. ^Minelli, Alessandro (2011).Treatise on Zoology - Anatomy, Taxonomy, Biology. The Myriapoda.BRILL. p. 459.ISBN978-90-04-15611-1.
  24. ^Wesener, Thomas; Moritz, Leif (2018-12-17)."Checklist of the Myriapoda in Cretaceous Burmese amber and a correction of the Myriapoda identified by Zhang (2017)"(PDF).Check List.14(6): 1131–1140.doi:10.15560/14.6.1131.ISSN1809-127X.
  25. ^abShear, William A.; Edgecombe, Gregory D. (2010). "The geological record and phylogeny of the Myriapoda".Arthropod Structure & Development.39(2–3): 174–190.doi:10.1016/j.asd.2009.11.002.PMID19944188.
  26. ^Gai, Yonghua; Song, Daxiang; Sun, Hongying; Yang, Qun; Zhou, Kaiya (2008)."The complete mitochondrial genome ofSymphylellasp. (Myriapoda: Symphyla): Extensive gene order rearrangement and evidence in favor of Progoneata ".Molecular Phylogenetics and Evolution.49(2): 574–585.doi:10.1016/j.ympev.2008.08.010.PMID18782622.
  27. ^Regier, Jerome C.; Wilson, Heather M.; Shultz, Jeffrey W. (2005). "Phylogenetic analysis of Myriapoda using three nuclear protein-coding genes".Molecular Phylogenetics and Evolution.34(1): 147–158.doi:10.1016/j.ympev.2004.09.005.PMID15579388.
  28. ^Jin, Ya-Li; Godeiro, Nerivania Nunes; Bu, Yun (2023-05-04)."Description of the first species of Scutigerella (Symphyla, Scutigerellidae) from China, with mitogenomic and genetic divergence analysis".ZooKeys(1157): 145–161.doi:10.3897/zookeys.1157.99686.ISSN1313-2970.PMC10193434.PMID37215163.

Further reading[edit]

  • C. A. Edwards (1990). "Symphyla". In Daniel L. Dindal (ed.).Soil Biology Guide.New York: Wiley. pp. 891–910.ISBN978-0-471-04551-9.
  • U. Scheller (1961). "A review of the Australian Symphyla (Myriapoda)".Australian Journal of Zoology.9(1): 140–171.doi:10.1071/ZO9610140.
  • U. Scheller (1982)."Symphyla".In Sybil P. Parker (ed.).Synopsis and Classification of Living Organisms.New York: McGraw-Hill. pp.688–689.ISBN978-0-07-079031-5.
  • R. J. Tillyard (1930). "The evolution of the class Insecta".Papers and Proceedings of the Royal Society of Tasmania.1930:1–89.

External links[edit]

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