Symphyla

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Symphyla
Temporal range: 99–0  Ma
Scutigerella 116012425.jpg
Scutigerella sp. (Scutigerellidae)
Garden Centipede-Symphyla sp. (8578774949).jpg
Scollopendrellid symphylan (Scolopendrellidae)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Symphyla
Ryder, 1880
Families

Scutigerellidae
Scolopendrellidae

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. [1] [2] More than 200 species are known worldwide. [3]

Contents

Symphyla are primarily herbivores and detritus feeders 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). They consume decaying vegetation, but can do considerable harm in an agricultural setting by consuming seeds, roots, and root hairs in cultivated soil. [1] [2] For example, the garden symphylan, Scutigerella immaculata can be a pest of crops. A species of Hanseniella has been recorded as a pest of sugar cane and pineapples in Queensland. [5] [6] A few species are found in trees [7] [8] and in caves. [9] A species of Symphylella has been shown to be predominantly predatory, [10] and some species are saprophagous.

Description

Several individuals of Scutigerella sp., showing their small size Scutigerella 63392733.jpg
Several individuals of Scutigerella sp., showing their small size

Symphyla are small, cryptic myriapods without eyes and without pigment. [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 in Hanseniella magna , which attains lengths of 12-13 mm (0.5 in). [11]

The head has long, segmented antennae, a postantennal organ, three pairs of mouthparts: 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-like organs of Tömösváry, which probably sense vibrations, are attached to the base of the antennae, as they are in centipedes. [2]

The trunk comprises 14 segments, which is covered by microhairs on the lateral and ventral integument, and by a various number of dorsal tergal plates, from 15 in Scutigerella and Hanseniella, and up till 24 in Ribautiella, increasing the flexibility of the body. Legs are found on the first 12 segments. The 13th segment, which is fused with the 12th segment, bears a pair of spinnerets that resembles cerci, and the 14th segment has a pair of long sensory hairs (trichobothria). Around the anal opening there is a small telson. [12] [13] [14] [15] Symphylans have been reported as living up to four years, and moult throughout their life. [2] Immature individuals have six or seven pairs of legs on hatching, but they add an additional pair at each moult until the adult instar, which usually has twelve pairs of legs. [16] [17] This mode of development is known as hemianamorphosis. [18] Although most adult symphylans have twelve leg pairs, the first pair is absent or vestigial in some species (e.g., those in the genus Symphylella ), so adults in some species have only eleven leg pairs. [19] [20] The species with 12 pairs are the only myriapods with actual legs on the first body segment, as the first pair of legs is modified into forcipules in centipedes, and in pauropods the segment is a reduced collum which bears ventrally a pair of small papillae, while in millipedes it's a collum without any appendages at all. [21]

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 adult Scutigerella immaculata Garden centipede (Scutigerella immaculata) life stages.jpg
Life stages of symphylans: eggs, juvenile, and adult Scutigerella immaculata

Symphylans breathe through a pair of spiracles on the sides of their head, and are the only arthropods with spiracle openings on the head. [22] These are connected to a system of tracheae that 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, or spermatophores, 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]

The spinnerets produce secretions that turn into a silk-like thread. [23] One fossil species, Symphylella patrickmuelleri, was found preserved in Burmese Amber releasing long threads of silk. [24] The silk plays a role in reproduction: the male deposits up to 450 spermatophores on stalks of silk. [25] Symphylans have also been reported releasing silk as a defense [26] and to suspend themselves in the air. [2]

Fossil record and evolution

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 in Burmese amber from the middle Cretaceous, approximately 99 million years ago. As a result, both families are thought to have diverged before the end of the Mesozoic Era. [27] [28] [29]

Despite their common name, morphological studies commonly place symphylans as more closely related to millipedes and pauropods than the centipedes, in the clade Progoneata. [30] [31] Molecular studies have shown conflicting results, with some supporting the Progoneata clade, others aligning symphylans with centipedes or other arthropods, although some are weakly supported. [32] [30] The clade is believed to be monophyletic. [33]

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">Pauropoda</span> Class of arthropods

Pauropoda is a class of small, pale, millipede-like arthropods in the subphylum Myriapoda. More than 900 species in twelve families are found worldwide, living in soil and leaf mold. Pauropods look like centipedes or millipedes and may be a sister group of the latter, but a close relationship with Symphyla has also been posited. The name Pauropoda derives from the Greek pauros and pous or podus, 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.

<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">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.

Nannarrup is a genus of soil centipedes in the family Mecistocephalidae; this genus includes a single species, Nannarrup hoffmani, also known as Hoffman's dwarf centipede. This centipede was discovered in Central Park in New York City and was the first new species to be discovered in that park in more than a century. This species is the smallest species in the family Mecistocephalidae, reaching only 10.3 mm in length, and has only 41 pairs of legs, the minimum number recorded in this family.

<span class="mw-page-title-main">Arthropod</span> Phylum of invertebrates with jointed exoskeletons

Arthropods are invertebrates in the phylum Arthropoda. They possess an exoskeleton with a cuticle made of chitin, often mineralised with calcium carbonate, a body with differentiated (metameric) segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species.

<i>Geophilus flavus</i> Species of centipede

Geophilus flavus is a terrestrial, soil-dwelling, species of centipede in the Geophilidae family. G. flavus occurs in a range of habitats across central Europe, North America, Australia and other tropical regions. Geophilomorph centipedes, like centipedes generally, are primary predators, hunting predominantly in underground soil burrows or above ground leaf litter. Their consumption behaviours are influenced by environment and seasonal factors. Given their lack of economic value and marginal medical significance, G.flavus remains largely understudied in mainstream research. Some recent studies have detailed the evolutionary development of G.flavus and Geophilidae generally, illustrating developed predatory features like forcipule venom glands.

<span class="mw-page-title-main">Himantariidae</span> Family of centipedes

Himantariidae is a monophyletic family of centipedes in the order Geophilomorpha and superfamily Himantarioidea, found almost exclusively in the Northern Hemisphere. Centipedes in this family feature a short head with a concave labral margin bearing a row of denticles, a single dentate lamella and some pectinate lamellae on each mandible, second maxillae with strongly tapering telopodites and slightly spatulate claws, and a stout forcipular segment with short forcipules and a wide tergite; the ultimate legs usually have no pretarsus, and the female gonopods are distinct and biarticulate.

<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.

<i>Siphoniulus</i> Genus of millipedes

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.

<span class="mw-page-title-main">Mecistocephalidae</span> Family of centipedes

Mecistocephalidae is a monophyletic family of centipedes in the order Geophilomorpha. It is the only family in the suborder Placodesmata. Most species in this family live in tropical or subtropical regions, but some occur in temperate regions. This family is the third most diverse in the order Geophiliomorpha, with about 170 species, including about 130 species in the genus Mecistocephalus.

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">Scolopendrellidae</span> Family of many-legged arthropods

Scolopendrellidae is a family of symphylans in the class Symphyla. There are about 9 genera and at least 100 described species in Scolopendrellidae.

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

Scutigerellidae is a family of pseudocentipedes in the class Symphyla. There are about 5 genera and at least 140 described species in Scutigerellidae.

<i>Scutigerella immaculata</i> Species of many-legged arthropod

Scutigerella immaculata, commonly known as the garden symphylan or glasshouse symphylid, is a species of myriapod in the family Scutigerellidae. It may have originated in Europe but now has a cosmopolitan distribution and can be a pest of crops.

Burmese amber is fossil resin dating to the early Late Cretaceous Cenomanian age recovered from deposits in the Hukawng Valley of northern Myanmar. It is known for being one of the most diverse Cretaceous age amber paleobiotas, containing rich arthropod fossils, along with uncommon vertebrate fossils and even rare marine inclusions. A mostly complete list of all taxa described up to the end of 2023 can be found in Ross (2024).

Geophilus arenarius is a species of soil centipede in the family Geophilidae. This centipede is found in Algeria. As part of the carpophagus species-complex, this species is closely related to both G. carpophagus and G. easoni.

<i>Scutigerella</i> Genus of symphylans

Scutigerella is a genus of symphylans with sub-cosmopolitan distribution. It is the second-largest clade in the family Scutigerellidae, comprising 38 species.

References

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  2. 1 2 3 4 5 6 7 Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. pp. 817–818. ISBN   978-0-03-056747-6.
  3. ↑ "ITIS - Report: Symphyla". www.itis.gov. Retrieved 2024-02-28.
  4. 1 2 3 4 Penny Greenslade (2002-03-31). "Class: Symphyla". Australian Faunal Directory . Australian National University. Archived from the original on 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, Hanseniella sp., 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 of Hanseniella 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 . S2CID   89444581.
  8. ↑ S. Clark & P. Greenslade (1996). "Review of Tasmanian Hanseniella Bagnall (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). "Symphylella sp. (Symphyla: Scolopendrellidae predators of arthropods and nematodes in grassland soils". Pedobiologia. 33 (2): 113–116. Bibcode:1989Pedob..33..113W. doi:10.1016/S0031-4056(24)00190-2.
  11. ↑ Scheller, U. (1996) https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1440-6055.1996.tb01391.x
  12. ↑ Multicellular Animals: Volume II: The Phylogenetic System of the Metazoa
  13. ↑ The Invertebrates: A Synthesis
  14. ↑ Biology of Arthropoda
  15. ↑ Intestinal Microorganisms of Termites and Other Invertebrates
  16. ↑ "Garden Symphylans". Integrated Pest Management on Peppermint-IPMP3.0. Oregon State University. Archived from the original on 2007-08-03. Retrieved 2007-07-02.
  17. ↑ "Symphylans". Entry: Symphylans. Encyclopedia of Arkansas . Retrieved 2021-05-29.
  18. ↑ 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.
  19. ↑ Szucsich, Nikola; Scheller, Ulf (2011). "Symphyla". In Minelli, Alessandro (ed.). The Myriapoda. Volume 1. Leiden: Brill. pp. 445–466. ISBN   978-90-04-18826-6. OCLC   812207443.
  20. ↑ 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, ISBN   978-0-12-384720-1 , retrieved 2022-02-28
  21. ↑ Textbook of Arthropod Anatomy
  22. ↑ BIOLOGICAL SCIENCE FUNDAMENTALS AND SYSTEMATICS - Volum III
  23. ↑ "X: The Symphyla" (PDF). Arthropod Anatomy. JSTOR   10.7591/j.ctvn1tb6g.14.
  24. ↑ 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. ISSN   0195-6671.
  25. ↑ "Symphylans". Encyclopedia of Arkansas. Retrieved 2023-05-02. 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.
  26. ↑ Schulze, L. (Jan 1975), Structure, composition and properties of spun products
  27. ↑ Moritz, Leif; Wesener, Thomas (2017). "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.
  28. ↑ Minelli, Alessandro (2011). Treatise on Zoology - Anatomy, Taxonomy, Biology. The Myriapoda. BRILL. p. 459. ISBN   978-90-04-15611-1.
  29. ↑ 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)". Check List. 14 (6): 1131–1140. doi: 10.15560/14.6.1131 . ISSN   1809-127X. S2CID   92289899.
  30. 1 2 Shear, William A.; Edgecombe, Gregory D. (2010). "The geological record and phylogeny of the Myriapoda". Arthropod Structure & Development. 39 (2–3): 174–190. Bibcode:2010ArtSD..39..174S. doi:10.1016/j.asd.2009.11.002. PMID   19944188.
  31. ↑ Gai, Yonghua; Song, Daxiang; Sun, Hongying; Yang, Qun; Zhou, Kaiya (2008). "The complete mitochondrial genome of Symphylella sp. (Myriapoda: Symphyla): Extensive gene order rearrangement and evidence in favor of Progoneata". Molecular Phylogenetics and Evolution. 49 (2): 574–585. Bibcode:2008MolPE..49..574G. doi:10.1016/j.ympev.2008.08.010. PMID   18782622.
  32. ↑ 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. Bibcode:2005MolPE..34..147R. doi:10.1016/j.ympev.2004.09.005. PMID   15579388.
  33. ↑ 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. Bibcode:2023ZooK.1157..145J. doi: 10.3897/zookeys.1157.99686 . ISSN   1313-2970. PMC   10193434 . PMID   37215163.

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