Theridiosoma Temporal range: | |
---|---|
T. gemmosum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Order: | Araneae |
Infraorder: | Araneomorphae |
Family: | Theridiosomatidae |
Genus: | Theridiosoma O. Pickard-Cambridge, 1879 [1] |
Type species | |
T. gemmosum (L. Koch, 1877) | |
Species | |
33, see text | |
Synonyms [1] | |
|
Theridiosoma is a genus of ray spiders that was first described by Octavius Pickard-Cambridge in 1879. [3] They use their web as a high speed slingshot to actively hunt for prey.
Mature spiders in this genus have a body length of 0.5–2.5 mm. The carapace ranges from dark brown to light tan, sometimes with distinct markings around the eye region or fovea, The sternum is smooth, with sparse bristles, and is usually darker towards the margin. A pit organ is present on the anterior margin of the sternum, at both corners. The abdomen is ovoid in shape, and taller than wide or long; the dorsal side of the abdomen often bears a light, thin median band and/or symmetrical light spots, the ventral side is dark. The metatarsi of the legs are typically shorter than the tibiae. As with other spiders in the family, the tibiae of the 3rd and 4th legs bear a group of long, vibration-sensitive trichobothria. Species in this genus exhibit only slight sexual dimorphism; males are similar to females in colouration but are slightly smaller, with proportionally longer legs. [4] [5]
The eyes are all approximately equal in size. The PME are very close together, sometimes touching, separated by less than half their diameter. The AME are also close together, but are typically separated by around half their diameter. [4]
This genus is found throughout the world. [5] Their preferred habitat is typical for the family; they construct a web in wet, shaded understories of forests, [4]
All species construct a vertical orb web in dark, damp places. At the end of web construction, the radial threads are fused at the centre so that only four, the "rays", reach the hub. The spider's rear legs are used to hold these rays while the front legs hold onto an extra line of thread, which is used to pull the web into a cone and keep it under tension. When potential prey nears the web the spider releases the tension in the web, causing it to slam into the prey. The spider then bites the prey, and wraps it in silk. [5] The speeds with which the spiders slingshot themselves is very high; speeds exceeding 4.1m/s with accelerations exceeding 1300m/s2 have been observed. [6]
As of June 2020 [update] it contains thirty-three species, found in Oceania, Asia, Central America, Africa, South America, North America, Europe, and the Caribbean: [1]
Formerly included:
Anyphaenidae is a family of araneomorph spiders, sometimes called anyphaenid sac spiders. They are distinguished from the sac spiders of the family Clubionidae and other spiders by having the abdominal spiracle placed one third to one half of the way anterior to the spinnerets toward the epigastric furrow on the underside of the abdomen. In most spiders the spiracle is just anterior to the spinnerets. Like clubionids, anyphaenids have eight eyes arranged in two rows, conical anterior spinnerets and are wandering predators that build silken retreats, or sacs, usually on plant terminals, between leaves, under bark or under rocks. There are more than 600 species in over 50 genera worldwide.
Theridiosomatidae, commonly known as Ray Spiders, are a family of araneomorph spiders first described by Eugène Simon in 1881. The family includes 137 species divided between 20 genera. They are most recognizable for their construction of cone-shaped webs.
Telemidae, also known as long-legged cave spiders, is a family of small haplogyne spiders. Most are cave dwelling spiders with six eyes, though some do not have any eyes at all. There are about 104 described species in sixteen genera.
Argyrodes, also called dewdrop spiders, is a genus of comb-footed spiders that was first described by Eugène Louis Simon in 1864. They occur worldwide, and are best known for their kleptoparasitism. They can spin their own webs, but tend to invade and reside in their hosts' webs. This relationship can be commensal or even mutual if the dewdrop spider feeds on small trapped insects that are not eaten by the host. Some species can even prey upon the host.
Linothele is a genus of curtain web spiders that was first described by Ferdinand Karsch in 1879. All but one of the described species are from South America. The exception is L. septentrionalis from the far-away Bahamas, although it has certain features that suggest it may belong in another genus. Additionally, an undescribed species of Linothele is known from Panama.
Mimetus is a genus of pirate spiders in the family Mimetidae. They are found worldwide.
Andasta is a genus of ray spiders that was first described by Eugène Louis Simon in 1895.
Patrera is a genus of anyphaenid sac spiders first described by Eugène Simon in 1903.
Chthonos is a genus of South American ray spiders that was created by Jonathan A. Coddington in 1986 because the previous name was preoccupied. Originally placed with the Orb-weaver_spiders under the name Tecmessa, it was transferred to the ray spiders in 1986.
Epilineutes is a monotypic genus of South and Central American ray spiders containing the single species, Epilineutes globosus. The genus was first described by Jonathan A. Coddington in 1986. The single species was first described in 1896 under the name Andasta globosa, but has also been referred to as Theridiosoma globosum.
Naatlo is a genus of ray spiders that was first described by Jonathan A. Coddington in 1986.
Ogulnius is a genus of ray spiders that was first described by Octavius Pickard-Cambridge in 1882.
Wendilgarda is a genus of ray spiders that was first described by Eugen von Keyserling in 1886.
Plato is a genus of ray spider. The American biologist Jonathan A. Coddington named and circumscribed the genus in 1986. It is a Neotropical genus and it is limited to South America. As of 2018, nine species are recognized. They are found in caves and have a distinctive cubic egg sac. The generic name comes from the ancient Greek philosopher Plato.
Baalzebub is a genus of ray spiders first described by Jonathan A. Coddington in 1986. Spiders in this genus typically live in dark environments, like caves.