Archaeognatha

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Archaeognatha
Temporal range: Devonian–Recent [1] : 320 
Rock bristletail.JPG
Rock bristletail
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Subclass: Monocondylia
Haeckel, 1866
Order: Archaeognatha
Börner, 1904
Families [2]
Synonyms
  • Microcoryphia (Verhoeff 1904)
  • Trinemura (Crampton 1916)
  • Protothysanura (Crampton 1924 non Smith 1897)

The Archaeognatha are an order of apterygotes, known by various common names such as jumping bristletails. Among extant insect taxa they are some of the most evolutionarily primitive; they appeared in the Middle Devonian period at about the same time as the arachnids. Specimens that closely resemble extant species have been found as both body and trace fossils (the latter including body imprints and trackways) in strata from the remainder of the Paleozoic Era and more recent periods. [3] For historical reasons an alternative name for the order is Microcoryphia. [4]

Contents

Until the late 20th century the suborders Zygentoma and Archaeognatha comprised the order Thysanura; both orders possess three-pronged tails comprising two lateral cerci and a medial epiproct or appendix dorsalis. Of the three organs, the appendix dorsalis is considerably longer than the two cerci; in this the Archaeognatha differ from the Zygentoma, in which the three organs are subequal in length. [4] In the late 20th century, it was recognized that the order Thysanura was paraphyletic, thus the two suborders were each raised to the status of an independent monophyletic order, with Archaeognatha sister taxon to the Dicondylia, including the Zygentoma. [5]

The order Archaeognatha is cosmopolitan; it includes roughly 500 species in two families. [6] No species is currently evaluated as being at conservation risk. [7]

Description

Archaeognatha are small insects with elongated bodies and backs that are arched, especially over the thorax. Their abdomen ends in three long tail-like structures, of which the lateral two are cerci, while the medial filament, which is longest, is an epiproct. The tenth abdominal segment is reduced. [8] The antennae are flexible. The two large compound eyes meet at the top of the head, and there are three ocelli. The mouthparts are partly retractable, with simple chewing mandibles and seven-segmented maxillary palps which are commonly longer than the legs. [9] [1] : 341–343 

Unlike other insect orders, they do not have olfactory receptor-coreceptors (Orco), which have either been lost or were never present in the first place. [10] [11]

Archaeognatha differ from Zygentoma in various ways, such as their relatively small head, their bodies being compressed laterally (from side to side) instead of flattened dorsiventrally, and in their being able to use their tails to spring up to 30 cm (12 in) into the air if disturbed. They have eight pairs of short appendages called styli on abdominal segments 2 to 9. Family Machilidae is also unique among insects in possessing small muscleless styli on the second and third thoracic legs, [12] but are absent on the second pair of thoracic legs in some genera. [13] Similar stylets on the legs are absent in family Meinertellidae. [14] They have one or two pairs of eversible membranous vesicles on the underside of abdominal segments 1 to 7, which are used to absorb water and assisting with molting. [15] There are nine pairs of spiracles; two pairs on the thorax, and seven pairs on abdominal segments 2 to 8. [16] The pair of spiracles on the first abdominal segment has been lost. [17]

Lateral aspect of an archaeognathan, showing arched profile and abdominal styli Jumping Bristletails (15567941692).jpg
Lateral aspect of an archaeognathan, showing arched profile and abdominal styli
Head of a machilid, showing compound eyes, prominent maxillary palps, and detachable scales. Tete de Trigoniophthalmus alternatus.jpg
Head of a machilid, showing compound eyes, prominent maxillary palps, and detachable scales.
Drawing of a scale, much magnified, from a species in the family Machilidae Lubbock Machilis Scale p0437P.png
Drawing of a scale, much magnified, from a species in the family Machilidae

Further unusual features are that the abdominal sternites are each composed of three sclerites, and they cement themselves to the substrate before molting, often using their own feces as glue. [18] The body is covered with readily detached scales, that make the animals difficult to grip and also may protect the exoskeleton from abrasion. The thin exoskeleton offers little protection against dehydration, and they accordingly must remain in moist air, such as in cool, damp situations under stones or bark.

Etymology

The name Archaeognatha is derived from the Greek ἀρχαῖος, archaios, meaning 'ancient', and γνάθος, gnathos, meaning 'jaw'. This refers to the articulation of the mandibles, which are different from those of other insects. It was originally believed that Archaeognatha possessed a single phylogenetically primitive condyle each (thus the name "Monocondylia"), where all more derived insects have two, but this has since been shown to be incorrect; all insects, including Archaeognatha, have dicondylic mandibles, but archaeognaths possess two articulations that are homologous to those in other insects, though slightly different. [19]

An alternative name, Microcoryphia, [4] comes from the Greek μικρός, mikros, 'small', and κορυφή, koryphē, which in context means 'head'. [20]

Taxonomy

FamiliesNo. of SpeciesDefining NotesImage
Machilidae 250Most are restricted to rocky shorelinesNeed specific image
Meinertellidae 170 [21] Lack scales at base of hind legs and antennaeNeed specific image

Biology

Archaeognatha occur in a wide range of habitats. While most species live in moist soil, others have adapted to chaparral, and even sandy deserts. They feed primarily on algae, but also lichens, mosses, or decaying organic detritus.

Three types of mating behavior are known. In some species the male spins a silk thread (carrier thread) stretched out on the ground. On the thread there are droplets of sperm which the female will take up when her ovipositor makes contact. In others a packet of sperm (spermatophore) is deposited on the top of a short stalk. If a female takes up the sperm or not is often random, but in many species the male will try to lead the female's genitals over the sperm during courtship. A more direct way of fertilization occurs in species of the genus Petrobius, where the male place a droplet of sperm directly on the female's ovipositor. [22] [23] One hypothesis is that the external genitals of insects started as structures specialized for water-uptake, which could reach deeper crevices than the coxal vesicles, and over time the female would use it to take up sperm from the ground instead of water. [24] After fertilization she lays a batch of around 30 eggs in a suitable crevice. The young resemble the adults, and take up to two years to reach sexual maturity, depending on the species and conditions such as temperature and available food.

Unlike most insects, the adults continue to moult after reaching adulthood, and typically mate once at each instar. Archaeognaths may have a total lifespan of up to four years, longer than most larger insects. [1]

Related Research Articles

<span class="mw-page-title-main">Thysanura</span> Deprecated order of insects

Thysanura is the now deprecated name of what was, for over a century, recognised as an order in the class Insecta. The two constituent groups within the former order, the Archaeognatha and the Zygentoma, share several characteristics, such as of having three long caudal filaments, the lateral ones being the cerci, while the one between (telson) is a medial cerciform appendage, specifically an epiproct. They are also both wingless, and have bodies covered with fine scales, rather like the scales of the practically unrelated Lepidoptera. In the late 20th century, it was recognized that the two suborders were not sister taxa, therefore Thysanura was paraphyletic, and the two suborders were each raised to the status of an independent monophyletic order, with Archaeognatha sister taxon to the Dicondylia, including the Zygentoma.

Several wingless hexapods are known as bristletails:

<span class="mw-page-title-main">Apterygota</span> Subclass of insects

The name Apterygota is sometimes applied to a former subclass of small, agile insects, distinguished from other insects by their lack of wings in the present and in their evolutionary history; notable examples are the silverfish, the firebrat, and the jumping bristletails. Their first known occurrence in the fossil record is during the Devonian period, 417–354 million years ago. The group Apterygota is not a clade; it is paraphyletic, and not recognized in modern classification schemes. As defined, the group contains two separate clades of wingless insects: Archaeognatha comprises jumping bristletails, while Zygentoma comprises silverfish and firebrats. The Zygentoma are in the clade Dicondylia with winged insects, a clade that includes all other insects, while Archaeognatha is sister to this lineage.

The most recent understanding of the evolution of insects is based on studies of the following branches of science: molecular biology, insect morphology, paleontology, insect taxonomy, evolution, embryology, bioinformatics and scientific computing. It is estimated that the class of insects originated on Earth about 480 million years ago, in the Ordovician, at about the same time terrestrial plants appeared. Insects are thought to have evolved from a group of crustaceans. The first insects were landbound, but about 400 million years ago in the Devonian period one lineage of insects evolved flight, the first animals to do so. The oldest insect fossil has been proposed to be Rhyniognatha hirsti, estimated to be 400 million years old, but the insect identity of the fossil has been contested. Global climate conditions changed several times during the history of Earth, and along with it the diversity of insects. The Pterygotes underwent a major radiation in the Carboniferous while the Endopterygota underwent another major radiation in the Permian.

<span class="mw-page-title-main">Entognatha</span> Class of wingless and ametabolous arthropods

The Entognatha are a class of wingless and ametabolous arthropods, which, together with the insects, makes up the subphylum Hexapoda. Their mouthparts are entognathous, meaning that they are retracted within the head, unlike the insects. Entognatha are apterous, meaning that they lack wings. The class contains three orders: Collembola, Diplura and Protura. These three groups were historically united with the now-obsolete order Thysanura to form the class Apterygota, but it has since been recognized that the hexapodous condition of these animals has evolved independently from that of insects, and independently within each order. The orders might not be closely related, and Entognatha is now considered to be a polyphyletic group.

<span class="mw-page-title-main">Machilidae</span> Family of jumping bristletails

The Machilidae are a family of insects belonging to the order Archaeognatha. There are around 250 described species worldwide. These insects are wingless, elongated and more or less cylindrical with a distinctive humped thorax and covered with tiny, close-fitting scales. The colour is usually grey or brown, sometimes intricately patterned. There are three "tails" at the rear of the abdomen: two cerci and a long central epiproct. They have large compound eyes, often meeting at a central point. They resemble the silverfish and the firebrat, which are from a different order, Zygentoma.

<span class="mw-page-title-main">Zygentoma</span> Order of insects

Zygentoma are an order in the class Insecta, and consist of about 550 known species. The Zygentoma include the so-called silverfish or fishmoths, and the firebrats. A conspicuous feature of the order are the three long caudal filaments. The two lateral filaments are cerci, and the medial one is an epiproct or appendix dorsalis. In this they resemble the Archaeognatha, although the cerci of Zygentoma, unlike in the latter order, are nearly as long as the epiproct.

<span class="mw-page-title-main">Meinertellidae</span> Family of jumping bristletails

The Meinertellidae are a small family of basal insects belonging to the order Archaeognatha. They are sometimes known as rock bristletails. These insects can be distinguished from members of the other Archaeognatha family, Machilidae, by the lack of scales at the base of the legs and antennae, head, and palps; along with possession of small abdominal sternites protruding slightly between the coxal plates. They can also be distinguished by patches of reddish to violet-brown hypodermal pigment on the appendages.

<span class="mw-page-title-main">Silverfish</span> Small land insect in the order Zygentoma

The silverfish is a species of small, primitive, wingless insect in the order Zygentoma. Its common name derives from the insect's silvery light grey colour, combined with the fish-like appearance of its movements. The scientific name indicates that the silverfish's diet consists of carbohydrates such as sugar or starches. While the common name silverfish is used throughout the global literature to refer to various species of Zygentoma, the Entomological Society of America restricts use of the term solely for Lepisma saccharinum.

<span class="mw-page-title-main">Dicondylia</span> Unranked taxon between Insecta and Pterygota

The Dicondylia are a taxonomic group (taxon) that includes all insects except the jumping bristletails (Archaeognatha). Dicondylia have a mandible attached with two hinges to the head capsule (dicondyl), in contrast to a hypothetical ancestral mandible with a single ball joint (monocondyl); the members of Archaeognatha do in fact have dicondylic mandibles, though they are not identical to the structure seen in "true" dicondylic insects.

Most insects reproduce oviparously, i.e. by laying eggs. The eggs are produced by the female in a pair of ovaries. Sperm, produced by the male in one testis or more commonly two, is transmitted to the female during mating by means of external genitalia. The sperm is stored within the female in one or more spermathecae. At the time of fertilization, the eggs travel along oviducts to be fertilized by the sperm and are then expelled from the body ("laid"), in most cases via an ovipositor.

Coreamachilis is a genus of jumping bristletails in the family Machilidae. There is at least one described species in Coreamachilis, C. coreanus.

Haslundichilis is a genus of jumping bristletails in the family Machilidae. There are at least two described species in Haslundichilis.

Heteropsontus is a genus of jumping bristletails in the family Machilidae. There is one described species in Heteropsontus, H. americanus.

Leptomachilis is a genus of jumping bristletails in the family Machilidae. There is one described species in Leptomachilis, L. californica.

Metagraphitarsus is a genus of jumping bristletails in the family Machilidae.

Meximachilis is a genus of jumping bristletails in the family Machilidae. There are at least three described species in Meximachilis.

Pseudocatamachilis is a genus of jumping bristletails in the family Machilidae. There is at least one described species in Pseudocatamachilis, P. torquata.

<i>Tricholepidion</i> Species of silverfish

Tricholepidion is a genus of wingless insect belonging to Zygentoma, with only a single described species T. gertschi, native to the northern coast of California in Western North America. It lives under dead bark and in rotting wood of conifers in mesophytic forests. It is alternatively considered the only living member of the family Lepidotrichidae, which also includes Lepidotrix from Eocene aged European amber, or the only member of the family Tricholepidiidae. The taxonomic position of Tricholepidion is uncertain, in some molecular phylogenetics studies it has been recovered as less closely related to flying insects (Pterygota) than the rest of Zygentoma is, rendering Zygentoma paraphyletic. Each compound eye contains ~40 ommatidia, and they have three ocelli. Scales on the body are absent. Unlike Archaeognatha and the other families of Zygentoma, which have three- and sometimes two-segmented tarsi, they have five-segmented tarsi like many winged insects.

<i>Petridiobius arcticus</i> Species of jumping bristletail

Petridiobius arcticus is a species of jumping bristletail in the family Machilidae. It is found in Europe and Northern Asia and North America.

References

  1. 1 2 3 Howell V. Daly; John T. Doyen & Alexander H. Purcell (1998). Introduction to Insect Biology and Diversity (2nd ed.). Oxford University Press. ISBN   0-19-510033-6.
  2. ↑ "Order Archaeognatha Börner 1904". The Paleobiology Database . Retrieved 26 November 2020.
  3. ↑ Patrick R. Getty; Robert Sproule; David L. Wagner & Andrew M. Bush (2013). "Variation in wingless insect trace fossils: insights from neoichnology and the Pennsylvanian of Massachusetts". PALAIOS. 28 (4): 243–258. Bibcode:2013Palai..28..243G. doi:10.2110/palo.2012.p12-108r. S2CID   86430759.
  4. 1 2 3 Timothy J. Gibb (27 October 2014). Contemporary Insect Diagnostics: The Art and Science of Practical Entomology. Academic Press. pp. 78–. ISBN   978-0-12-404692-4.
  5. ↑ A. Blanke, M. Koch, B. Wipfler, F. Wilde, B. Misof (2014) Head morphology of Tricholepidion gertschi indicates monophyletic Zygentoma. Frontiers in Zoology 11:16 doi:10.1186/1742-9994-11-16
  6. ↑ Barnard, Peter C. (19 September 2011). The Royal Entomological Society Book of British Insects. ISBN   9781444344967.
  7. ↑ NC State University, ENT 425 | General Entomology | Resource Library | Compendium [Archeognatha]
  8. ↑ Gillot, Cedric (14 March 2013). Entomology. ISBN   9781461569183.
  9. ↑ Resh, Vincent H.; Cardé, Ring T. (22 July 2009). Encyclopedia of Insects. ISBN   9780080920900.
  10. ↑ Wicher, D.; Miazzi, F. (2021). "Functional properties of insect olfactory receptors: Ionotropic receptors and odorant receptors". Cell and Tissue Research. 383 (1): 7–19. doi:10.1007/s00441-020-03363-x. PMC   7873100 . PMID   33502604.
  11. ↑ Brand, Philipp; Robertson, Hugh M.; Lin, Wei; Pothula, Ratnasri; Klingeman, William E.; Jurat-Fuentes, Juan Luis; Johnson, Brian R. (2018). "The origin of the odorant receptor gene family in insects". eLife. 7. doi:10.7554/eLife.38340. PMC   6080948 . PMID   30063003.
  12. ↑ Snodgrass, R. E. (31 May 2018). Principles of Insect Morphology. ISBN   9781501717918.
  13. ↑ Mendes, Luís F. (1990). "An Annotated List of Generic and Specific Names of Machilidae (Microcoryphia, Insecta) with Identification Keys for the Genera and Geographical Notes".
  14. ↑ Sturm, Helmut (1997). "A New Subgenus and Two New Species of the Genus Machilinus (Meinertellidae, Archaeognatha = Microcoryphia, "Apterygota", Insecta) from Mexico". Journal of the New York Entomological Society. 105 (1/2): 15–23. JSTOR   25010224.
  15. ↑ McGavin, George C.; Davranoglou, Leonidas-Romanos (4 January 2023). Essential Entomology. ISBN   978-0-19-265483-0.
  16. ↑ Davies, R. G. (11 November 2013). Outlines of Entomology. ISBN   9789401705080.
  17. ↑ Proceedings of the 1st Dresden Meeting on Insect Phylogeny: "Phylogenetic Relationships within the Insect Orders". (Dresden, September 19-21, 2003)
  18. ↑ Abbott, John C.; Abbott, Kendra (13 October 2020). Common Insects of Texas and Surrounding States. ISBN   9781477310359.
  19. ↑ Blanke, Alexander; Machida, Ryuichiro; Szucsich, Nikolaus Urban; Wilde, Fabian; Misof, Bernhard (2015). "Mandibles with two joints evolved much earlier in the history of insects: Dicondyly is a synapomorphy of bristletails, silverfish and winged insects". Systematic Entomology. 40 (2): 357–364. doi:10.1111/syen.12107. S2CID   85309726.
  20. ↑ H. G. Liddell (1889). An Intermediate Greek-English Lexicon: Based on the 7th Ed of Liddell & Scott's Lexicon.
  21. ↑ Song, Zhi-Shun; Huang, Fu-Sheng; Liang, Ai-Ping (2011). "Machilontus (s. str.) medogensis Song & Huang, sp. nov. from Tibet, the northernmost record of the genus Machilontis Silvestri, 1912 and the first record of the family Meinertellidae (Insecta: Microcoryphia: Machiloidea) in China". Zootaxa. 2822: 61. doi:10.11646/zootaxa.2822.1.4.
  22. ↑ Walker, Andrew A.; Church, Jeffrey S.; Woodhead, Andrea L.; Sutherland, Tara D. (2013). "Silverfish silk is formed by entanglement of randomly coiled protein chains". Insect Biochemistry and Molecular Biology. 43 (7): 572–579. doi:10.1016/j.ibmb.2013.03.014. PMID   23578395.
  23. ↑ Klass, Klaus-Dieter; Matushkina, Natalia A. (2012). "The exoskeleton of the female genitalic region in Petrobiellus takunagae (Insecta: Archaeognatha): Insect-wide terminology, homologies, and functional interpretations". Arthropod Structure & Development. 41 (6): 575–591. doi:10.1016/j.asd.2012.06.003. PMID   22766521.
  24. ↑ 9th Dresden Meeting on Insect Phylogeny 2019
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