The brown recluse, Sicariidae is a recluse spider with necrotic venom. Similar to those of other recluse spiders, their bites sometimes require medical attention. The brown recluse is one of three spiders in North America with medically significant venom, the others being the black widow and the Chilean recluse.
Atracidae is a family of mygalomorph spiders, commonly known as Australian funnel-web spiders or atracids. It has been included as a subfamily of the Hexathelidae, but is now recognized as a separate family. All members of the family are native to Australia. Atracidae consists of three genera: Atrax, Hadronyche, and Illawarra, comprising 35 species. Some members of the family produce venom that is dangerous to humans, and bites by spiders of six of the species have caused severe injuries to victims. The bites of the Sydney funnel-web spider and northern tree-dwelling funnel-web spider are potentially deadly, but no fatalities have occurred since the introduction of modern first-aid techniques and antivenom.
Agelenopsis, commonly known as the American grass spiders, is a genus of funnel weavers first described by C.G. Giebel in 1869. They weave sheet webs that have a funnel shelter on one edge. The web is not sticky, but these spiders make up for that shortcoming by running very rapidly. The larger specimens can grow to about 19 mm in body length. They may be recognized by the arrangement of their eight eyes into three rows. The top row has two eyes, the middle row has four eyes, and the bottom row has two eyes. They have two prominent hind spinnerets, somewhat indistinct bands on their legs, and two dark bands running down either side of the cephalothorax.
The Pholcidae are a family of araneomorph spiders. The family contains over 1,800 individual species of pholcids, including those commonly known as cellar spider, daddy long-legs spider, carpenter spider, daddy long-legger, vibrating spider, gyrating spider, long daddy, and skull spider. The family, first described by Carl Ludwig Koch in 1850, is divided into 94 genera.
The Agelenidae are a large family of spiders in the suborder Araneomorphae. Well-known examples include the common "grass spiders" of the genus Agelenopsis. Nearly all Agelenidae are harmless to humans, but the bite of the hobo spider may be medically significant, and some evidence suggests it might cause necrotic lesions, but the matter remains subject to debate. The most widely accepted common name for members of the family is funnel weaver.
Tegenaria is a genus of fast-running funnel weavers that occupy much of the Northern Hemisphere except for Japan and Indonesia. It was first described by Pierre André Latreille in 1804, though many of its species have been moved elsewhere. The majority of these were moved to Eratigena, including the giant house spider and the hobo spider.
The spider species Tegenaria domestica, commonly known as the barn funnel weaver in North America and the domestic house spider in Europe, is a member of the funnel-web family Agelenidae.
The giant house spider has been treated as either one species, under the name Eratigena atrica, or as three species, E. atrica, E. duellica and E. saeva. As of April 2020, the three species view was accepted by the World Spider Catalog. They are among the largest spiders of Central and Northern Europe. They were previously placed in the genus Tegenaria. In 2013, they were moved to the new genus Eratigena as the single species Eratigena atrica. In 2018, the three separate species were restored. The bite of these species does not pose a threat to humans or pets, and they are generally reluctant to bite, preferring instead to hide or escape.
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.
The rare spider species Tegenaria silvestris is mostly found in caves, or on dumps; sometimes it occurs on forest edges, or in dry forests. It constructs its web under tree trunks and dead wood, and in tree caves.
Tegenaria parietina is a rather rare spider in Europe, with a distribution also including Northern Africa to Central Asia and Sri Lanka, and from the West Indies to Uruguay and Argentina, where it may have been introduced. In the UK it is sometimes known as the cardinal spider because of the legend that Cardinal Wolsey was terrified by this species at Hampton Court, or, conversely, because he regarded them as lucky and forbade anyone to harm them. In 2013, Tegenaria taprobanica was included in this species.
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.
Agelenopsis aperta, also known as the desert grass spider or funnel-web spider, is a species of spider belonging to the family Agelenidae and the genus Agelenopsis. It is found in dry and arid regions across the southern United States and into northwestern Mexico. Their body is about 13–18 mm long and they have relatively long legs in order to run after their prey. Desert grass spiders can withstand very low temperatures even though they do not cold harden. It constructs the characteristic funnel-shaped webs in crevices where the funnel will fit, where they wait in the tube for prey which they can run after using their long legs. They often hunt for their prey at night.
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.
Eratigena is a genus of spider in the family Agelenidae. Most of its species were moved from the genus Tegenaria in 2013. Which is what this genus is named after, being an anagram of Tegenaria. Two species that frequently build webs in and around human dwellings are now placed in this genus. Eratigena agrestis is the hobo spider, native to Europe and Central Asia, introduced to North America. Eratigena atrica is the giant house spider, native to Europe and also introduced into North America.
Aterigena is a genus of funnel weavers first described by A. Bolzern, A. Hänggi & D. Burckhardt in 2010. The name is an anagram of Tegenaria. It was created in 2010 for a group of Tegenaria and Malthonica species that formed a clade in a phylogenetic analysis. The genus was later found to be monophyletic, further separating Eratigena from Tegenaria and Malthonica.
Agelenopsis emertoni is a species of funnel weaver in the family of spiders known as Agelenidae. It is found in the United States. The spider was named to honour arachnologist James H. Emerton. A. emertoni is distinguished from other Agelenopsis species in the genus by the male's loosely coiling embolus making more than one full circle, and a claw-like conductor tip. These features are sclerites of the male sex organ which is used to inseminate the female. The female has a distinctive conducting tube in her genitalia. The male can be between 6 and 13mm. Distribution is in the following states of the USA: Arkansas, Colorado, Florida, Georgia, Louisiana, Massachusetts, Mississippi, Missouri, New Jersey, New York, North Carolina, Oklahoma, Pennsylvania, Tennessee, Texas, Virginia.
Agelenopsis pennsylvanica, commonly known as the Pennsylvania funnel-web spider or the Pennsylvania grass spider, is a species of spider in the family Agelenidae. The common name comes from the place that it was described, Pennsylvania, and the funnel shape of its web. Its closest relative is Agelenopsis potteri.
Eratigena duellica, the giant house spider, is a species of funnel weaver in the spider family Agelenidae. It is found in Canada, the United States, and Europe. The related species Eratigena atrica is also called the giant house spider.
