|Solifugid from Arizona|
Solifugae is an order of animals in the class Arachnida known variously as camel spiders, wind scorpions, sun spiders, or solifuges. The order includes more than 1,000 described species in about 153 genera. Despite the common names, they are neither true scorpions (order Scorpiones) nor true spiders (order Araneae). Much like a spider, the body of a solifugid has two tagmata: an opisthosoma (abdomen) behind the prosoma (that is, in effect, a combined head and thorax). At the front end, the prosoma bears two chelicerae that, in most species, are conspicuously large. The chelicerae serve as jaws and in many species also are used for stridulation. Unlike scorpions, solifugids do not have a third tagma that forms a "tail". Most species of Solifugae live in dry climates and feed opportunistically on ground-dwelling arthropods and other small animals. The largest species grow to a length of 12–15 cm (5–6 in), including legs. A number of urban legends exaggerate the size and speed of the Solifugae, and their potential danger to humans, which is negligible.
In biological classification, the order is
In biological classification, class is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order.
Arachnida is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Spiders are the largest order in the class, which also includes scorpions, ticks, mites, harvestmen, and solifuges. In 2019, a molecular phylogenetic study also placed horseshoe crabs in Arachnida.
Solifugae are moderately small to large arachnids (a few millimeters to several centimeters in body length), with the larger species reaching 12–15 cm (5–6 in) in length, including legs. In practice, the respective lengths of the legs of various species differ drastically, so the resulting figures are often misleading. More practical measurements refer primarily to the body length, quoting leg lengths separately, if at all. The body length is up to 7 cm (3 in). Most species are closer to 5 cm (2 in) long, and some small species are under 1 cm (0.4 in) in head-plus-body length when mature.
Like that of the spider order, the Araneae, the body plan of the Solifugae has two main tagmata: the prosoma, or cephalothorax, is the anterior tagma, and the 10-segmented abdomen, or opisthosoma, is the posterior tagma. As shown in the illustrations, the solifugid prosoma and opisthosoma are not separated by nearly as clear a constriction and connecting tube or "pedicel" as occurs in "true spiders", the order Araneae. The lack of the pedicel reflects another difference between the Solifugae and spiders, namely that solifugids lack both spinnerets and silk, and do not spin webs. Spiders need considerable mobility of their abdomens in their spinning activities, and the Solifugae have no need for any such adaptation.
In biology, a tagma is a specialized grouping of multiple segments or metameres into a coherently functional morphological unit. Familiar examples are the head, the thorax, and the abdomen of insects. The segments within a tagma may be either fused or so jointed as to be independently moveable.
The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax. This fusion of the head and thorax is seen in chelicerates and crustaceans; in other groups, such as the Hexapoda, the head remains free of the thorax. In horseshoe crabs and many crustaceans, a hard shell called the carapace covers the cephalothorax.
Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans.
The prosoma comprises the head, the mouthparts, and the somites that bear the legs and the pedipalps. The alternative name "cephalothorax" reflects the fact that the prosoma includes the parts that in insects form the head plus the thorax. Though it is not split into two clear tagmata, the prosoma does have a large, relatively well-defined anterior carapace, bearing the animal's eyes and chelicerae, while a smaller posterior section bears the legs.
Somites are divisions of the body of an animal or embryo. The divisions are also known as metameric segments.
Like pseudoscorpions and harvestmen, the Solifugae lack book lungs, having instead a well-developed tracheal system that inhales and exhales air through a number of spiracles; one pair between the second and third pair of walking legs, two pairs on the abdomen on abdominal segments three and four, and an unpaired spiracle on the fifth abdominal segment.
A pseudoscorpion, also known as a false scorpion or book scorpion, is an arachnid belonging to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida.
A book lung is a type of respiration organ used for atmospheric gas exchange that is found in many arachnids, such as scorpions and spiders. Each of these organs is found inside an open ventral abdominal, air-filled cavity (atrium) and connects with the surroundings through a small opening for the purpose of respiration.
Among the most distinctive features of the Solifugae are their large chelicerae, which in many species are longer than the prosoma. Each of the two chelicerae has two articles (segments, parts connected by a joint),forming a powerful pincer, much like that of a crab; each article bears a variable number of teeth, largely depending on the species. The chelicerae of many species are surprisingly strong; they are capable of shearing hair or feathers from vertebrate prey or carrion, and of cutting through skin and thin bones such as those of small birds. Many Solifugae stridulate with their chelicerae, producing a rattling noise.
The chelicerae are the mouthparts of the Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", some chelicerae, such as those found in spiders, are hollow and contain venom glands, and are used to inject venom into prey or a (perceived) threat.
Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mechanism is typically that of one structure with a well-defined lip, ridge, or nodules being moved across a finely-ridged surface or vice versa, and vibrating as it does so, like the dragging of a phonograph needle across a vinyl record. Sometimes it is the structure bearing the file which resonates to produce the sound, but in other cases it is the structure bearing the scraper, with both variants possible in related groups. Common onomatopoeic words for the sounds produced by stridulation include chirp and chirrup.
Like most other arachnids, although Solifugae appear to have five pairs of legs, only the hind four pairs actually are "true" legs. Each true leg has seven segments: coxa, trochanter, femur, patella, tibia, metatarsus, and tarsus.
The first, or anterior, of the five pairs of leg-like appendages are not "actual" legs, but pedipalps, and they have only five segments each. The pedipalps of the Solifugae function partly as sense organs similar to insects' antennae, and partly in locomotion, feeding, and fighting. In normal locomotion, they do not quite touch the ground, but are held out to detect obstacles and prey; in that attitude, they look particularly like an extra pair of legs or perhaps arms. Reflecting the great dependence of the Solifugae on their tactile senses, their anterior true legs commonly are smaller and thinner than the posterior three pairs. That smaller anterior pair acts largely in a sensory role as a supplement to the pedipalps, and in many species they accordingly lack tarsi. At the tips of their pedipalps, Solifugae bear eversible adhesive organs, which they may use to capture flying prey, and which at least some species certainly use for climbing smooth surfaces.
For the most part, only the posterior three pairs of legs are used for running.On the undersides of the coxae and trochanters of the last pair of legs, Solifugae have fan-shaped sensory organs called malleoli or racquet (or racket) organs. Sometimes, the blades of the malleoli are directed forward, sometimes not. They have been suspected to be sensory organs for the detection of vibrations in the soil, perhaps to detect threats and potential prey or mates. These structures may be chemoreceptors.
Males are usually smaller than females, with relatively longer legs.Unlike females, the males bear a pair of flagella, one on each chelicera. In the accompanying photograph of a male solifugid, one flagellum is just visible near the tip of each chelicera. The flagella, which bend back over the chelicerae, are sometimes called horns and are believed to have some sexual connection, but their function has not yet been clearly explained.
Some species have very large central eyes. They look like simple eyes or ocelli, and are surprisingly sophisticated. They can recognise forms, and are used in hunting and avoiding enemies. These eyes are remarkable in their internal anatomy; they may represent the last step in the integration of the aggregate of simple ocelli into a compound eye, and of further integration of a compound eye into a simple eye.In contrast, lateral eyes are absent in many species, and where they are present at all, they are only rudimentary.
The Solifugae are an order of their own, though are sometimes confused with spiders, which form a completely distinct order, the Araneae. The order comprises over 1000 described species in 153 genera assigned to the following 12 families: 213:
The family Protosolpugidae is only known from one fossil species from the Pennsylvanian.
Although the Solifugae are considered to be endemic indicators of desert biomes, 1 they occur widely in semidesert and scrub. Some species also live in grassland or forest habitats. Solifugae generally inhabit warm and arid habitats, including virtually all warm deserts and scrublands in all continents except Antarctica and Australia.:
Solifugae are carnivorous or omnivorous, with most species feeding on termites, darkling beetles, and other small, ground-dwelling arthropods. Solifuges are aggressive hunters and voracious opportunistic feeders and have been recorded as feeding on snakes, small lizards, and rodents.Prey is located with the pedipalps and killed and cut into pieces by the chelicerae. The prey is then liquefied and the liquid ingested through the pharynx. Although they do not normally attack humans, their chelicerae can penetrate human skin, and painful bites have been reported.
Various other predators, such as the large slit-faced bat, scorpions, toads, and insectivores, may prey on Solifugae.
Solifugae are typically univoltine (reproducing once a year). 8 Reproduction can involve direct or indirect sperm transfer; when indirect, the male emits a spermatophore on the ground and then inserts it with his chelicerae in the female's genital pore. To do this, he flings the female on her back.:
The female then digs a burrow, into which she lays 50 to 200 eggs – some species then guard them until they hatch. Because the female does not feed during this time, she will try to fatten herself beforehand, and a species of 5 cm (2.0 in) has been observed to eat more than 100 flies during that time in the laboratory. Solifugae undergo a number of stages including, egg, postembryo, 9–10 nymphal instars, and adults.
The name Solifugae derives from Latin, and means "those that flee from the sun". The order is also known by the names Solpugida, Solpugides, Solpugae, Galeodea, and Mycetophorae. Their common names include camel spider, wind scorpion, scorpion carrier, jerrymunglum,sun scorpion, and sun spider. In southern Africa, they are known by a host of names, including red romans, haarskeerders ("hair cutters") and baardskeerders ("beard cutters"), the latter two relating to the belief they use their formidable jaws to clip hair from humans and animals to line their subterranean nests.
Solifugids have been recognised as distinct taxa from ancient times. The Greeks recognized that they were distinct from spiders; spiders were called ἀράχνη (arachne) while Solifugae were named φαλάγγιον (phalangion). In Aelian's De natura animalium, they are mistakenly mentioned, along with scorpions, as responsible for the abandoning of a country in Ethiopia. Anton August Heinrich Lichtenstein theorised in 1797 that the "mice" that plagued the Philistines in the Old Testament were Solifugae.[ citation needed ] During World War I, troops [ clarification needed ] stationed in Abū Qīr, Egypt, would stage fights between captive "jerrymanders," as they referred to them, and placed bets on the outcome. Similarly, British troops stationed in Libya in World War II would stage fights between solifugids and scorpions. :2–3
Solifugae are the subject of many legends and exaggerations about their size, speed, behaviour, appetite, and lethality. They are not especially large, the biggest having a leg span of about 12 cm (4.7 in). They are fast on land compared to other invertebrates, with their top speed estimated to be 16 km/h (10 mph), close to half as fast as the fastest human sprinter.
The Solifugae apparently have neither venom glands nor any venom-delivery apparatus such as the fangs of spiders, stings of wasps, or venomous setae of caterpillars (e.g., Lonomia or Acharia species).One 1978 study is frequently quoted, in which the authors report detection of an exception in India, in that Rhagodes nigrocinctus had venom glands, and that injection of the secretion into mice was frequently fatal. However, no supporting studies have confirmed either statement, such as by independent detection of the glands as claimed, or the relevance of the observations, if correct. Even the authors of the original account denied having found any means of delivery of the putative venom by the animal, and the only means of administering the material to the mice was by parenteral injection. Given that many non-venoms such as saliva, blood and glandular secretions can be lethal if injected, and that no venomous function was even speculated upon in this study, there is still no evidence for even one venomous species of solifugid.
Because of their unfamiliar spider-like appearance and rapid movements, Solifugae have startled or even frightened many people. This fear was sufficient to drive a family from their home when one was allegedly discovered in a soldier's house in Colchester, England, and caused the family to blame the solifugid for the death of their pet dog.An Arizona resident developed painful lesions due to a claimed solifugid bite but could not produce a specimen for confirmation. Though they are not venomous, the powerful chelicerae of a large specimen may inflict a painful nip, but nothing medically significant.
The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda. It contains the sea spiders, arachnids, and several extinct lineages, such as the eurypterids.
Amblypygi is an ancient order of arachnid chelicerate arthropods also known as whip spiders and tailless whip scorpions. The name "amblypygid" means "blunt tail", a reference to a lack of the flagellum that is otherwise seen in whip scorpions. They are harmless to humans. Amblypygids possess no silk glands or venomous fangs. They rarely bite if threatened, but can grab fingers with their pedipalps, resulting in thorn-like puncture injuries.
Schizomida is an order of arachnids, generally less than 5 millimetres (0.20 in) in length.
The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, or daddy longlegs. As of April 2017, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.
The order Ricinulei is a group of arachnids known as hooded tickspiders, though they are not true spiders. Like most arachnids, they are predatory, eating small arthropods. In older works they are sometimes referred to as Podogona.
The Acari are a taxon of arachnids that contains mites and ticks. The diversity of the Acari is extraordinary and their fossil history goes back to at least the early Devonian period. Acarologists have proposed a complex set of taxonomic ranks to classify mites. In most modern treatments, the Acari are considered a subclass of the Arachnida and are composed of two or three superorders or orders: Acariformes, Parasitiformes, and Opilioacariformes; the latter is often considered a subgroup within the Parasitiformes. The monophyly of the Acari is open to debate, and the relationships of the acarines to other arachnids is not at all clear. In older treatments, the subgroups of the Acarina were placed at order rank, but as their own subdivisions have become better understood, treating them at the superorder rank is more usual.
Pedipalps are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and anterior to the first pair of walking legs.
Ammotrechidae is a family of solifuges distributed in the Americas and the Caribbean Islands. It includes 22 described genera and at least 83 species. Members of this family can be distinguished from members of other families by the absence of claws on tarsi of leg I, tarsal segmentation 1-2-2-(2-4), pedipalps with pairs of lateroventral spines, and by males having an immovable flagellum on the mesal face of each chelicerum. The propeltidium of the Ammotrechidae is recurved.
The anatomy of spiders includes many characteristics shared with other arachnids. These characteristics include bodies divided into two tagmata, eight jointed legs, no wings or antennae, the presence of chelicerae and pedipalps, simple eyes, and an exoskeleton, which is periodically shed.
Opiliones are an order of arachnids and share many common characteristics with other arachnids. However, several differences separate harvestmen from other arachnid orders such as spiders. The bodies of opliones are divided into two tagmata : the abdomen (opisthosoma) and the cephalothorax (prosoma). Unlike spiders, the juncture between the abdomen and cephalothorax is often poorly defined. Harvestmen have chelicerae, pedipalps and four pairs of legs. Most harvestmen have two eyes, although there are eyeless species.
Tarantulas comprise a group of large and often hairy spiders belonging to the family Theraphosidae. Currently, about 1,000 species have been identified. The term tarantula is usually used to describe members of the family Theraphosidae, although many other members of the same infraorder (Mygalomorphae) are commonly referred to as "tarantulas" or "false tarantulas". Some of the more common species have become popular in the exotic pet trade. New World species kept as pets have urticating hairs that can cause irritation to the skin, and in extreme cases, cause damage to the eyes.
Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs able to inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every habitat with the exceptions of air and sea colonization. As of July 2019, at least 48,200 spider species, and 120 families have been recorded by taxonomists. However, there has been dissension within the scientific community as to how all these families should be classified, as evidenced by the over 20 different classifications that have been proposed since 1900.
Chelypus ('clawfoot') is a genus of slow-moving, burrowing sunspiders confined to the deserts and arid regions of Southern Africa. There are 6 known species.
Malleolus (plural: malleoli) is a fan-shaped chemoreceptor or Racquet Organ, an array of which are carried in pairs on the ventral or undersides of Solpugidae. They are the counterpart of pectines in scorpions, and modified walking limbs in the uropygids and amblypygids. Most species have 5 pairs of malleoli on the ventral surface of the fourth pair of legs of both sexes, while juveniles and other species have 2-3 pairs.
In most animals the central pathways of olfactory systems are associated with glomerular neuropil and lack topographic mapping of sensory inputs. Among arthropods, the insect and crustacean olfactory (antennal) pathways are typical examples. Two orders of chelicerate arthropods, the scorpions and solpugids (Cl. Arachnida), present striking exceptions to this generalization. The major chemosensory organs of scorpions are the pectines, two ventral appendages that contact the substrate intermittently as the animal searches for food or mates. In solpugids chemosensory input is from the antennalized pedipalps and first leg pairs, and from ten fan-shaped malleoli extending ventrally to the substrate from the 4th leg pair. The pectinal and malleolar sensory systems have highly ordered arrangement of 105 to 106 primary chemoreceptors, with one (pectines) forming a two-dimensional array and the other (malleoli) assembled in a linear array. The spatial frequencies of these chemoreceptive inputs exceed 100/mm and 1000/mm, respectively, indicating a capacity for resolving structure of chemical deposits on substrates. Using several histological and axonal tracing techniques, the organization of pectinal and malleolar central projections has been resolved. The pectinal projection terminates posteriorly in the cephalothoracic mass and shows a high degree of topographic precision, perhaps to the level of individual receptors in the sensory field. This chemosensory 'map' is imposed on laminar cytoarchitecture posteriorly in the brain but merges anteriorly into glomerular substructures. The sensory projection from the malleoli shows less topographic order with fewer and larger glomeruli reminiscent of the insect olfactory system. These comparisons between arthropod taxa suggest that olfactory projections are, to varying degrees, typically glomerular but may evolve topographic and laminar organization when the stimulus field is of fixed form.
Chanbria is a genus of camel spiders. It consists of four species found in the Sonoran Desert in Mexico and the southwestern United States.
Chimerarachne is a genus of extinct arachnids containing a single species Chimerarachne yingi. Fossils of Chimerarachne were discovered in Burmese amber from Myanmar which dates to the mid-Cretaceous, about 100 million years ago. Its classification is disputed, either belonging to Uraraneida a group otherwise known from the Devonian to Permian, or a separate clade closer to spiders. Since the earliest spider fossils are from the Carboniferous, either answer results in an at least a 170 myr ghost lineage with no fossil record, making it a Lazarus taxon. The size of the animal is quite small, being only 2.5 mm in body length, with the tail being about 3mm in length. These fossils resemble spiders in having two of their key defining features: spinnerets for spinning silk, and a modified male organ on the pedipalp for transferring sperm. At the same time they retain a whip-like tail, rather like that of a whip scorpion and uraraneids. Chimerarachne is not ancestral to spiders, being much younger than the oldest spiders which are known from the Carboniferous, but it appears to be a late survivor of an extinct group which was probably very close to the origins of spiders. It suggests that there used to be spider-like animals with tails which lived alongside true spiders for at least 200 million years.
Kingdom - Animalia Animal, animaux, animals.
Camel Spider Feeding by Stefan F. Wirth
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