| Loxosceles gaucho | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Arachnida |
| Order: | Araneae |
| Infraorder: | Araneomorphae |
| Family: | Sicariidae |
| Genus: | Loxosceles |
| Species: | L. gaucho |
| Binomial name | |
| Loxosceles gaucho Heineken & Lowe, 1832 | |
Loxosceles gaucho commonly known in English as the gaucho spider. [1] is a highly venomous recluse spider endemic to South America.
Adult females grow up to 7–12 mm, the maximum reported is 14 mm. They are mainly characterized by their brown color, leading to them be colloquially referred to as ''Aranha marrom'' (Portuguese for brown spider) in Brazil, the body is characterized by a pale to dark brown color (often reddish), with a dorsal violin-shaped mark, slightly darker on the carapace, with long and slender legs, without dark marks or stripes. Males have the thoracic region with the clearest impression, consisting of bands, with the anterior portion of the cephalothorax forming in the rear direction a '' V '' design, while pedipalps have the last short articles and curved stylus. Females have the anterior portion of the cephalothorax forming a '' U '' shape backwards. Like many recluse spiders, It is nocturnal, hunting preys such as insects and arthropods with their strong webs, and is more active in the hottest seasons of the year. [1] [2]
They usually spin irregular webs in cracks, crevices and corners (which is why some people call them the corner spider), along or under large rocks. It often can be found in human's houses, in dark places, like clothes, shoes, socks and other parts of the house, this species mainly occurs in Central and Southern Brazil, but have been introduced to Tunisia. [1]
One study of 81 cases of cutaneous and cutaneous-hemolytic loxoscelism, from a geographical area where most accidents are caused by L. gaucho, reported bite-related symptoms such as massive hemolysis and acute kidney injury (in two cases). In 25 cases, an increase in serum bilirubin and LDH was observed, suggestive of hemolysis. anemia (14.7%), reticulocytosis (56%), thrombocytopenia (17.6%), an increase in D-dimer and fever were also reported. [3] A study with the venom of L. gaucho showed the main local bite reactions, such as pain, edema, erythema, ecchymosis, pallor and dermonecrosis, and systemic like Hemolysis. [4] In the state of São Paulo alone, Brazil, it is responsible for causing viscerocutaneous loxoscelism in 3.1% of cases. [5]
The brown recluse, Loxosceles reclusa, Sicariidae is a recluse spider with a necrotic venom. Similar to other recluse spider bites, their bite sometimes requires medical attention. The brown recluse is one of three spiders with medically significant venom in North America.
The chelicerae are the mouthparts of the Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly to pincers. Some chelicerae, such as those found on nearly all spiders, are hollow and contain venom glands, and are used to inject venom into prey or a perceived threat. In Pisaurina mira, also known as the nursery web spider, the chelicerae are utilized to snatch the prey once it becomes within reach, facilitating the "sit-and-wait ambush predator" behavior. Both pseudoscorpions and harvestmen have structures on their chelicerae that are used for grooming.
The recluse spiders, also known as brown spiders, fiddle-backs, violin spiders, and reapers, is a genus of spiders that was first described by R. T. Lowe in 1832. They are venomous spiders known for their bite, which sometimes produces a characteristic set of symptoms known as loxoscelism.
Sicariidae is a family of six-eyed venomous spiders known for their potentially necrotic bites. The family consists of three genera and about 160 species. Well known spiders in this family include the brown recluse spider and the six-eyed sand spider.
The Mediterranean recluse spider is a species of spider that originated in the Mediterranean region as its name implies, but can now be found in many parts of the world.
A spider bite, also known as arachnidism, is an injury resulting from the bite of a spider. The effects of most bites are not serious. Most bites result in mild symptoms around the area of the bite. Rarely they may produce a necrotic skin wound or severe pain.
Sphingomyelin phosphodiesterase D (EC 3.1.4.41, sphingomyelinase D) is an enzyme of the sphingomyelin phosphodiesterase family with systematic name sphingomyelin ceramide-phosphohydrolase. These enzymes catalyse the hydrolysis of sphingomyelin, resulting in the formation of ceramide 1-phosphate and choline:
Sicarius is a genus of recluse spiders that is potentially medically significant to humans. It is one of three genera in its family, all venomous spiders known for a bite that can induce loxoscelism. They live in deserts and arid regions of the Southern Hemisphere, and females use a mixture of sand and silk when producing egg sacs. Most are native to South America, with the exception of Central America's S. rugosus, known primarily for its self-burying behavior. The name is Latin for assassin.
The Chilean recluse spider, Loxosceles laeta, is a highly venomous spider of the family Sicariidae. In Spanish, it is known as araña de rincón, or "corner spider"; in Brazilian Portuguese, as aranha-marrom or "brown spider". It is considered by many to be the most dangerous of recluse spiders, and its bites often result in serious systemic reactions, up to and including death.
Loxoscelism is a condition occasionally produced by the bite of the recluse spiders. The area becomes dusky and a shallow open sore forms as the skin around the bite dies (necrosis). It is the only proven type of necrotic arachnidism in humans. While there is no known therapy effective for loxoscelism, there has been research on antibiotics, surgical timing, hyperbaric oxygen, potential antivenoms and vaccines. Because of the number of diseases that may mimic loxoscelism, it is frequently misdiagnosed by physicians.
Loxosceles deserta, commonly known as the desert recluse, is a brown spider of the family Sicariidae.
The pathophysiology of a spider bite is due to the effect of its venom. A spider envenomation occurs whenever a spider injects venom into the skin. Not all spider bites inject venom – a dry bite, and the amount of venom injected can vary based on the type of spider and the circumstances of the encounter. The mechanical injury from a spider bite is not a serious concern for humans. Some spider bites do leave a large enough wound that infection may be a concern. However, it is generally the toxicity of spider venom that poses the most risk to human beings; several spiders are known to have venom that can cause injury to humans in the amounts that a spider will typically inject when biting.
Sicarius thomisoides is a species of spider in the family Sicariidae, found in Chile. It is the type species of the genus Sicarius. Its correct name has been the source of confusion. It has often been known by the synonym Sicarius terrosus, a name which has also often been used incorrectly for other species.
Sicarius ornatus is a species of venomous spider found in South America (Brazil). It has a highly toxic venom like the other South American sicariid, Loxosceles laeta and the African Hexophthalma hahni, but there are few human bites recorded. Its venom has active sphingomyelinase D, and can lead to a severe pathology.
Sicarius tropicus is a species of six-eyed sand spider (Sicarius) endemic in South American caatinga in Brazil. Like related spiders, it is venomous, but only one medically-significant bite has been recorded, causing dermonecrotic lesions in a 17-year-old boy.
Loxosceles intermedia, the Brazilian brown recluse spider, is a highly venomous spider species in the family Sicariidae native to Brazil and Argentina.
Loxosceles similis, is a species of a venomous recluse spider endemic to South America.
List of reported attacks and species involved in Latin America.
Loxosceles adelaida is a species of venomous recluse spider found in South America.
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