The evolutionary ancestry of arthropods dates back to the Cambrian period. The group is generally regarded as monophyletic, and many analyses support the placement of arthropods with cycloneuralians (or their constituent clades) in a superphylum Ecdysozoa. Overall, however, the basal relationships of animals are not yet well resolved. Likewise, the relationships between various arthropod groups are still actively debated. Today, arthropods contribute to the human food supply both directly as food, and more importantly, indirectly as pollinators of crops. Some species are known to spread severe disease to humans, livestock, and crops. (Full article...)
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Female
Zygoballus sexpunctatus is a species of jumping spider which occurs in the southeastern United States where it can be found in a variety of grassy habitats. Adult spiders measure between 3 and 4.5 mm in length. The cephalothorax and abdomen are bronze to black in color, with reddish brown or yellowish legs. The male has distinctive enlarged chelicerae (the mouthparts used for grasping prey) and front femora (the third, and typically largest, leg segments). Like many jumping spiders, Z. sexpunctatus males exhibit ritualized courtship and agonistic behavior. (Full article...)
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Illustration of PWL 2014/5186-LSb, the counterpart portion of the holotype specimen of P. salgadoi
Pruemopterus is a genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Pruemopterus, P. salgadoi, is known only from a single fossil specimen discovered in geological deposits of Early Devonian age in Germany. The name of the genus is derived from the Prüm river and the surrounding Prüm valley, which contains the finding place of the fossil, and the Ancient Greekπτερόν (pteron, "wing"), referring to the eurypterid swimming paddles, and the species name honors the Brazilian photographer and photojournalist Sebastião Salgado.
Pruemopterus was a very small adelophthalmid eurypterid, with the only known specimen measuring about 2.5 centimeters (0.98 in) in length. Although superficially similar to the related genus Parahughmilleria, Pruemopterus can be distinguished from other adelophthalmids by several features, most notably its wide and vaguely rectangular carapace (head plate) and its rounded, rather than elongated, eyes. Pruemopterus lived alongside other Early Devonian animals, including several other eurypterid genera, in a shallow brackish to fresh water environment. (Full article...)
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Phengaris rebeli (formerly Maculinea rebeli), common name mountain Alcon blue, is a species of butterfly in the family Lycaenidae. It was first found and described in Styria, Austria, on Mount Hochschwab around 1700. Although it was initially classified as a subspecies of P. alcon, a European researcher, Lucien A. Berger, designated it as a separate species in 1946. Genetic similarities between P. rebeli and P. alcon have led many researchers to argue that the two are the same species and differences are due to intraspecific variation.
Although P. rebeli is found across the Palearctic (see subspecies), it is difficult to determine the species' precise range due to confusion with P. alcon.
Behavioral ecologists have found its role as a brood parasite to be of particular interest as, unlike many brood parasites, it does not directly oviposit in the hosts' nests. P. rebeli parasitizes the colony ant speciesMyrmica schencki as a larva by using chemical mimicry to trick the ants into believing that they are ant larvae; thus, the ants bring P. rebelicaterpillars back to their nests and feed them. P. rebeli is dependent on the plant Gentiana cruciata early in its life cycle and is vulnerable to parasitism by Ichneumon eumerus while inside the nest of M. schencki. It was placed on the IUCN Red List in 2000 and is classified as a species vulnerable to extinction. (Full article...)
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Fossil specimen of A. mansfieldi illustrated by James Hall
Adelophthalmus is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Adelophthalmus have been discovered in deposits ranging in age from the Early Devonian to the Early Permian, which makes it the longest lived of all known eurypterid genera, with a total temporal range of over 120 million years. Adelopththalmus was the final genus of the Eurypterina suborder of eurypterids and consisted the only known genus of swimming eurypterids from the Middle Devonian until its extinction during the Permian, after which the few surviving eurypterids were all walking forms of the suborder Stylonurina.
Fossils of Adelophthalmus have been described from four continents; North America, Europe, Asia and Australia, which indicates that Adelophthalmus might have had a nearly cosmopolitan (worldwide) distribution, one of few eurypterid genera to achieve one besides potentially Pterygotus. The territorial expansion of Adelophthalmus had begun early, with representatives found in both Siberia and Australia during the Devonian, but it first gained its almost cosmopolitan distribution following the amalgamation of the supercontinent Pangaea during the Carboniferous and Permian.
The generic name Adelophthalmus means "no obvious eye", referencing that the holotype fossil seemingly represented an eyeless eurypterid, with a carapace (head plate) completely lacking any indication of eyes. Though this has caused much subsequent confusion, including the naming of several junior synonyms, the apparent eyelessness of the type specimen is treated by modern researchers as a preservational artifact, and not a feature that any species of Adelophthalmus would have possessed in life. (Full article...)
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Y. geinitzi worker
Yantaromyrmex is an extinctgenus of ants first described in 2013. Members of this genus are in the subfamily Dolichoderinae of the family Formicidae, known from Middle Eocene to Early Oligocene fossils found in Europe. The genus currently contains five described species, Y. constrictus, Y. geinitzi, Y. intermedius, Y. mayrianum and Y. samlandicus. The first specimens were collected in 1868 and studied by Austrian entomologist Gustav Mayr, who originally placed the fossils in other ant genera until the fossils were reviewed and subsequently placed into their own genus. These ants are small, measuring from 4 to 6 mm (0.16 to 0.24 in) in length and can be characterized by their trapezoidal shaped head-capsules and oval compound eyes that are located slightly to the rear of the capsules midpoint, with no known ocelli present. (Full article...)
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Ant mimicry or myrmecomorphy is mimicry of ants by other organisms; it has evolved over 70 times. Ants are abundant all over the world, and potential predators that rely on vision to identify their prey, such as birds and wasps, normally avoid them, because they are either unpalatable or aggressive. Some arthropods mimic ants to escape predation (Batesian mimicry), while some predators of ants, especially spiders, mimic them anatomically and behaviourally in aggressive mimicry. Ant mimicry has existed almost as long as ants themselves; the earliest ant mimics in the fossil record appear in the mid-Cretaceous alongside the earliest ants.
In myrmecophily, mimic and model live commensally together; in the case of ants, the mimic is an inquiline in the ants' nest. Such mimics may in addition be Batesian or aggressive mimics. To overcome ants' powerful defences, mimics may imitate ants chemically with ant-like pheromones, visually, or by imitating an ant's surface microstructure to defeat the ants' tactile inspections. (Full article...)
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The Colorado potato beetle (Leptinotarsa decemlineata) is also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle, or the potato bug. It is a major pest of potato crops. It is about 10 mm (3⁄8 in) long, with a bright yellow/orange body and five bold brown stripes along the length of each of its elytra. Native to the Rocky Mountains, it spread rapidly in potato crops across America and then Europe from 1859 onwards.
The meat ant (Iridomyrmex purpureus), also known as the gravel ant or southern meat ant, is a species of antendemic to Australia. A member of the genus Iridomyrmex in the subfamily Dolichoderinae, it was described by British entomologist Frederick Smith in 1858. The meat ant is associated with many common names due to its appearance, nest-building behaviour and abundance, of which its specific name, purpureus, refers to its coloured appearance. It is among the best-known species of ant found throughout Australia; it occurs in almost all states and territories except for Tasmania. Its enormous distribution, aggression and ecological importance have made this ant a dominant species.
The meat ant is monomorphic (occurs in a particular form), although there is evidence that certain populations can be polymorphic. It is characterised by its dark-bluish body and red head. It is a medium to large species, measuring 6–12 mm (0.24–0.47 in). The workers and males are approximately the same sizes at 6–7 mm (0.24–0.28 in) and 8 mm (0.31 in), respectively. The queens are the largest and appear mostly black, measuring 12.7 mm (0.50 in). The iridescence in workers ranges from green or blue to plain green and purple, varying in different body parts and castes. Meat ants inhabit open and warm areas in large, oval-shaped mounds that are accompanied by many entrance holes. The nest area is always cleared of vegetation and covered with materials including gravel, pebbles and dead vegetation. They are also polydomous, where a colony may be established in a series of satellite nests connected by well-defined paths and trails. Satellite nests are constructed away from the main nest and nearby areas with valuable food sources so workers can exploit them.
Queens mate with a single male and colonies may have more than one queen until the workers arrive, where they both exhibit antagonism. It takes around one or two months for an individual egg to develop into an adult. Colonies range in size, varying between 11,000 individuals to over 300,000. The meat ant is a diurnal species (active throughout most of the day), especially when it is warm. It forages on trees and collects sweet substances such as honeydew and nectar, and also captures insects or collects the remains of animals. A number of predators eat these ants, including the short-beaked echidna (Tachyglossus aculeatus), numerous species of birds, blind snakes and spiders. This species is also a competitor of the banded sugar ant (Camponotus consobrinus). Meat ants establish territorial borders with neighbouring colonies and solve disputes through ritualised fighting. (Full article...)
C. maenas is a widespread invasive species, listed among the 100 of the World's Worst Invasive Alien Species. It is native to the north-east Atlantic Ocean and Baltic Sea, but has colonised similar habitats in Australia, South Africa, South America and both Atlantic and Pacific coasts of North America. It grows to a carapace width of 90 mm (3+1⁄2 in), and feeds on a variety of mollusks, worms, and small crustaceans, affecting a number of fisheries. Its successful dispersal has occurred by a variety of mechanisms, such as on ships' hulls, sea planes, packing materials, and bivalves moved for aquaculture. (Full article...)
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Lycorma imperialis is a planthopperindigenous to parts of China and Indo-Malaysia. L. imperialis was originally discovered in 1846 by Adam White and has one recognized non-nominate subspecies, L. i. punicea. L. imperialis has undergone a number of reclassifications since its discovery and is one of four species in the genusLycorma. L. imperialis follows a hemimetabolous life cycle and will undergo a series of nymphal stages (instars) before maturing to an adult.
Lycorma imperialis and L. i. punicea are referred to as "lanternflies" or "lantern bugs" due to their crimson hindwings and their forewings, which can range from blue green to brick red. They do not, however, emit light. L. imperialis can cause substantial damage to agricultural industries due to its specialized, sap sucking mouthparts and the resulting mold that develops from its honeydew excrement. (Full article...)
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Scyllarides latus, the Mediterranean slipper lobster, is a species of slipper lobster found in the Mediterranean Sea and in the eastern Atlantic Ocean. It is edible and highly regarded as food, but is now rare over much of its range due to overfishing. Adults may grow to 1 foot (30 cm) long, are camouflaged, and have no claws. They are nocturnal, emerging from caves and other shelters during the night to feed on molluscs. As well as being eaten by humans, S. latus is also preyed upon by a variety of bony fish. Its closest relative is S. herklotsii, which occurs off the Atlantic coast of West Africa; other species of Scyllarides occur in the western Atlantic Ocean and the Indo-Pacific. The larvae and young animals are largely unknown. (Full article...)
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P. longiceps
Prionomyrmex is an extinct genus of bulldog ants in the subfamilyMyrmeciinae of the family Formicidae. It was first described by Gustav Mayr in 1868, after he collected a holotype worker of P. longiceps in Baltic amber. Three species are currently described, characterised by their long mandibles, slender bodies and large size. These ants are known from the Eocene and Late Oligocene, with fossil specimens only found around Europe. It is suggested that these ants preferred to live in jungles, with one species assumed to be an arboreal nesting species. These ants had a powerful stinger that was used to subdue prey. In 2000, it was suggested by Cesare Baroni Urbani that the living species Nothomyrmecia macrops and a species he described both belonged to Prionomyrmex, but this proposal has not been widely accepted by the entomological community. Instead, scientists still classify the two genera distinctive from each other, making Nothomyrmecia a valid genus. (Full article...)
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Brownimecia clavata holotype
Brownimecia is an extinctgenus of ants, the only genus in the tribeBrownimeciini and subfamily Brownimeciinae of the Formicidae. Fossils of the identified species, Brownimecia clavata and Brownimecia inconspicua, are known from the Late Cretaceous of North America. The genus is one of several ants described from Late Cretaceous ambers of New Jersey. Brownimecia was initially placed in the subfamily Ponerinae, until it was transferred to its own subfamily in 2003; it can be distinguished from other ants due to its unusual sickle-like mandibles and other morphological features that makes this ant unique among the Formicidae. B. clavata is also small, measuring 3.43 millimetres (0.135 in), and a stinger is present in almost all of the specimens collected. The morphology of the mandibles suggest a high level of feeding specialization. (Full article...)
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Avitomyrmex is an extinct genus of bulldog ants in the subfamily Myrmeciinae which contains three described species. The genus was described in 2006 from Ypresian stage (Early Eocene) deposits of British Columbia, Canada. Almost all the specimens collected are queens, with an exception of a single fossilised worker. These ants are large, and the eyes are also large and well-developed; a sting is present in one species. The behaviour of these ants may have been similar to extant Myrmeciinae ants, such as foraging solitarily for arthropod prey and never leaving pheromone trails to food sources. Avitomyrmex has not been assigned to any tribe, instead generally being regarded as incertae sedis within Myrmeciinae. However, its identity as an ant has been challenged, although it is undoubtedly a hymenopteran insect. (Full article...)
Beetles are insects that form the orderColeoptera (/koʊliːˈɒptərə/), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 described species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal species; new species are discovered frequently, with estimates suggesting that there are between 0.9 and 2.1 million total species. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae (ladybirds or ladybugs) eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops. Some others also have unique characteristics, such as the common eastern firefly, which uses a light-emitting organ for mating and communication purposes
Beetles typically have a particularly hard exoskeleton including the elytra, though some such as the rove beetles have very short elytra while blister beetles have softer elytra. The general anatomy of a beetle is quite uniform and typical of insects, although there are several examples of novelty, such as adaptations in water beetles which trap air bubbles under the elytra for use while diving. Beetles are holometabolans, which means that they undergo complete metamorphosis, with a series of conspicuous and relatively abrupt changes in body structure between hatching and becoming adult after a relatively immobile pupal stage. Some, such as stag beetles, have a marked sexual dimorphism, the males possessing enormously enlarged mandibles which they use to fight other males. Many beetles are aposematic, with bright colors and patterns warning of their toxicity, while others are harmless Batesian mimics of such insects. Many beetles, including those that live in sandy places, have effective camouflage.
Image 4 This fully-grown robber crab has tough fabric forming its joints, delicate biomineralized cuticle over its sensory antennae, optic-quality over its eyes, and strong, calcite-reinforced chitin armouring its body and legs; its pincers can break into coconuts (from Arthropod exoskeleton)
Image 5Mature queen of a termite colony, showing how the unsclerotised cuticle stretches between the dark sclerites that failed to stretch as the abdomen grew to accommodate her ovaries (from Arthropod exoskeleton)
Image 11This Zoea-stage larva is hardly recognisable as a crab, but each time it sheds its cuticle it remodels itself, eventually taking on its final crab form (from Arthropod exoskeleton)
Image 13Ghost crab, showing a variety of integument types in its exoskeleton, with transparent biomineralization over the eyes, strong biomineralization over the pincers, and tough chitin fabric in the joints and the bristles on the legs (from Arthropod exoskeleton)
Image 16Some of the various hypotheses of myriapod phylogeny. Morphological studies (trees a and b) support a sister grouping of Diplopoda and Pauropoda, while studies of DNA or amino acid similarities suggest a variety of different relationships, including the relationship of Pauropoda and Symphyla in tree c. (from Myriapoda)
Image 17Crab larva barely recognisable as a crab, radically changes its form when it undergoes ecdysis as it matures (from Arthropod exoskeleton)
Image 18In honeypot antrepletes, the abdomens of the workers that hold the sugar solution grow vastly, but only the unsclerotised cuticle can stretch, leaving the unstretched sclerites as dark islands on the clear abdomen (from Arthropod exoskeleton)
Image 25The house centipedeScutigera coleoptrata has rigid sclerites on each body segment. Supple chitin holds the sclerites together and connects the segments flexibly. Similar chitin connects the joints in the legs. Sclerotised tubular leg segments house the leg muscles, their nerves and attachments, leaving room for the passage of blood to and from the hemocoel (from Arthropod exoskeleton)
Image 26Formation of anterior segments across arthropod taxa based on gene expression and neuroanatomical observations, Note the chelicera(Ch) and chelifore(Chf) arose from somite 1 and thus correspond to the first antenna(An/An1) of other arthropods. (from Chelicerata)
The orb-weaver spiders (family Araneidae) are the familiar builders of spiral wheel-shaped webs often found in gardens, fields and forests. The family is a large one, including over 2800 species in over 160 genera worldwide, making it the third largest known (behind Salticidae and Linyphiidae). The web has always been thought of as an engineering marvel.
A European paper wasp (Polistes dominula) heating a bubble of regurgitated fluid in the sunlight. This is a common practice among many winged insects, and it is believed to be a way to facilitate digestion or to cool themselves off.
The Ozyptila praticola species of crab spider is found throughout Europe and the Middle East. They do not build webs to trap prey, but are active hunters. Crab spiders are so named because of their first two pairs of legs, which are held out to the side giving them a crab-like appearance. Also, like crabs, these spiders move sideways and backwards more easily than forwards.
The red rock crab (Grapsus grapsus) is one of the most common crabs along the western coast of the Americas. Adults are quite variable in color, including brownish-red, mottled or spotted brown, pink, yellow, bright orange and red. It feeds on algae primarily, sometimes sampling other plant matter and dead animals.
A fishing spider with two of its legs missing. Most likely some predator (a bird, or given its habitat a large fish or frog) grasped the spider by the missing limbs which were jettisoned by the spider in response, a process known as autotomy.
The Adonis blue (Polyommatus bellargus) is a butterfly in the family Lycaenidae, found in Europe and parts of West Asia. This photograph, taken in a chalk meadow at Yoesden Bank in Buckinghamshire, England, shows the underside of the folded wings of a male Adonis blue; the upper side is a bright, sky-blue.
The Globe Skimmer (Pantala flavescens) is the most widespread dragonfly species on the planet, found between about the 40th parallels of latitude, or where the annual mean temperature is above 20 °C (68 °F), except in Europe where there are only occasional sightings.
Xylotrupes socrates (Siamese rhinoceros beetle, or "fighting beetle"), male, on a banana leaf. This scarab beetle is particularly known for its role in insect fighting in Northern Laos and Thailand.
A male Roesel's bush-cricket (Metrioptera roeseli), a European bush-cricket named after August Johann Rösel von Rosenhof, a German entomologist. Its song is very similar to that of Savi's Warbler. Its body length as an adult insect is 15 to 18 mm. It is brown with a pale margin to the sides of the pronotum. Its forewings usually reach midway along its abdomen at rest. However there is a macropterous form of this insect (f. diluta), in which the wings reach beyond the tip of the abdomen. This form appears predominantly during hot summers and enables the species to extend its geographical range rapidly while conditions are suitable; such migrations may also be in response to local overpopulation.
Pieris brassicae, the large white, is a species of butterfly in the family Pieridae, common in Europe, Asia and North Africa. The larva pictured here, which was found at a market in Fronton, France, is a serious pest of plants in the cabbage family, Brassicaceae. The eggs are laid in batches on the undersides of the leaves of plants rich in mustard-oil glucosides, and consumption of these substances as they chew the leaves makes the larvae distasteful; the bright colouration of the larvae signals to predators that they taste bad. Additionally, the adult butterflies emit an unpleasant smell and display warning colours.
A macro view of a Gonia capitatafly feeding on honey, showing its proboscis and pedipalps (the two appendages protruding from the proboscis), two types of insect mouthparts. The proboscis actually comprises the labium, a quadrupedal structure, and a sponge-like labellum at the end. Flies eat solid food by secreting saliva and dabbing it over the food item. As the saliva dissolves the food, the solution is then drawn up into the mouth as a liquid. The labellum's surface is covered by minute food channels which form a tube leading to the esophagus, and food is drawn up the channels by capillary action.
Purana tigrina is a species of cicada found in Southeast Asia. This adult male was photographed in Kadavoor, Kerala, in southern India, and is about one inch (25 mm) in length. The mouthparts are adapted to piercing plant tissues and sucking sap; the male abdomen houses the tymbal, an organ used in the production of song, while the female abdomen is tipped by a large, saw-edged ovipositor.
Two Melangyna viridiceps (called Common Hoverflies in Australia) mating in mid-air. The male, which can be identified by the eyes meeting at the top of its head, is on top. The term "hoverfly" refers to about 6,000 species of flying insects in the family Syrphidae. They are often seen hovering at flowers and are important pollinators.
The longtail tadpole shrimp (Triops longicaudatus) is a freshwater crustacean resembling a miniature horseshoe crab. It is one of the oldest animal species still in existence. Like its relative Triops cancriformis, the longtail tadpole shrimp is considered a living fossil because its basic prehistoric morphology has changed little in the last 70 million years, exactly matching ancient fossils.
A female subimago of a March Brown mayfly (Rhithrogena germanica). Mayflies belong to the orderEphemeroptera, and the only insects that have a subimago phase. This stage is a favourite food of many fish, and many fishing flies are modeled to resemble them. They are aquatic insects whose nymph stage usually lasts one year in freshwater. The adults are short-lived, from as little as thirty minutes to a few days depending on the species.
The yellow fever mosquito (Aedes aegypti) is a species of mosquito known for its ability to spread yellow fever and dengue fever. The mosquito can be recognized by the white markings on its legs and a marking in the form of a lyre on its thorax. Though originally from Africa, the yellow fever mosquito can now be found in tropical regions around the world.
The red rock crab (Grapsus grapsus), also known as "Sally Lightfoot", is one of the commonest crabs along the western seaboard of the Americas. John Steinbeck wrote of them, "Everyone who has seen them has been delighted with them ... These little crabs, with brilliant cloisonné carapaces, walk on their tiptoes, they have remarkable eyes and an extremely fast reaction time." He tried to catch them but to little avail. "If you walk slowly, they move slowly ahead of you in droves. If you hurry, they hurry. When you plunge at them, they seem to disappear in a puff of blue smoke."
The light blue soldier crab (Mictyris longicarpus) inhabits beaches in the Indo-Pacific region. Soldier crabs filter sand or mud for microorganisms. They congregate during the low tide, and bury themselves in a corkscrew pattern during high tide, or whenever they are threatened.
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