Pedipalps are the secondary pair of forward appendages among 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.
The Mesothelae are a suborder of spiders. As of April 2024, two extant families were accepted by the World Spider Catalog, Liphistiidae and Heptathelidae. Alternatively, the Heptathelidae can be treated as a subfamily of a more broadly circumscribed Liphistiidae. There are also a number of extinct families.
Solifugae is an order of arachnids known variously as solifuges, sun spiders, camel spiders, and wind scorpions. The order includes more than 1,000 described species in about 147 genera. Despite the common names, they are neither true scorpions nor true spiders. Because of this, it is less ambiguous to call them "solifuges". Most species of solifuge 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 solifuges, and their potential danger to humans, which is negligible.
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 opiliones 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. Harvestmen were traditionally thought to have two eyes, except in the case of eyeless species. Developmental genetic work has shown that living species retain up to six eyes, including one pair of rudimentary median eyes and one pair of rudimentary lateral eyes.
Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. As of December 2023, 1,100 species have been identified, with 166 genera. 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. Many New World species kept as pets have setae known as 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 limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. 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 Antarctica, and have become established in nearly every land habitat. As of September 2024, 52,309 spider species in 134 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900.
Psalmopoeus irminia, also known as the Venezuelan suntiger, is a species of tarantula endemic to Venezuela, Guyana and Brazil. They were first described in 1994 by F. Saager.
This glossary describes the terms used in formal descriptions of spiders; where applicable these terms are used in describing other arachnids.
Agelena labyrinthica is a species of spider in the family Agelenidae. It is a widespread species in Europe and its range extends to Central and East Asia.
Aptostichus barackobamai is a large species of trapdoor spider in the family Euctenizidae named after the 44th President of the United States, Barack Obama. The species was first reported by Jason Bond of Auburn University in December 2012 as one of 33 new species of the genus Aptostichus. The species is endemic throughout northern California, forming burrows out of silk, dirt, and sand, from which it attacks prey. This spider is identified by its dark red to red-brown coloration with a stripped or chevron patterned abdomen. Breeding occurs during the winter and females tend to be larger than their male counterparts. A. barackobamai is part of the larger Aptostichus icenoglei species complex, and is a close relative to Aptostichus icenoglei and Aptostichus isabella.
Progradungula otwayensis, commonly known as the Otway odd-clawed spider, is a species of cribellate spider endemic to the Great Otway National Park of Victoria, Australia. It is one of only three species in the gradungulid genus Progradungula.
The two palpal bulbs – also known as palpal organs and genital bulbs – are the copulatory organs of a male spider. They are borne on the last segment of the pedipalps, giving the spider an appearance often described as like wearing boxing gloves. The palpal bulb does not actually produce sperm, being used only to transfer it to the female. Palpal bulbs are only fully developed in adult male spiders and are not completely visible until after the final moult. In the majority of species of spider, the bulbs have complex shapes and are important in identification.
Thiratoscirtus minimus is a species of jumping spider in the genus Thiratoscirtus that lives in Kenya. The species was first described in 2016 by Angelika Dawidowicz and Wanda Wesołowska. It is a medium-sized spider, with a cephalothorax] and an abdomen both typically 1.7 mm in length, although radically different in shape. The spider's carapace is oval and generally brown while its abdomen a narrower greyish-brown ovoid. The area around its eyes is black. It has yellow legs that are marked with grey rings and have multiple spines. The male has pedipalps that are similar to the related Thiratoscirtus gambari but has a smaller palpal tibia, which is recalled in the species name, which means "tiny".
Euophrys cochlea is a species of jumping spider in the genus Euophrys that is endemic to South Africa. The species was first described in 2014 by Wanda Wesołowska, Galina Azarkina and Anthony Russell-Smith. It is a medium-sized brown spider, with a body that consists of a cephalothorax that is between 1.7 and 2.4 mm long and an abdomen between 1.7 and 2.9 mm (0.11 in) long. The cephalothorax has a dark brown carapace, or topside. The spider's eye field is darker, with black rings around the eyes but marked with a white patch. The female has a yellowish-brown abdomen while the male is a darker brown. While the female has light brown to yellow legs, the male's legs whitish-yellow or yellowish-orange. The spider is most easily differentiated from others species in the genus by its screw-like embolus, part of the male's copulatory organs. This is recalled in the species name, the Latin word for screw.
Chimerarachne is a genus of extinct arachnids, containing five species. Fossils of Chimerarachne were discovered in Burmese amber from Myanmar which dates to the mid-Cretaceous, about 100 million years ago. It is thought to be closely related to spiders, but outside any living spider clade. The earliest spider fossils are from the Carboniferous, requiring at least a 170 myr ghost lineage with no fossil record. The size of the animal is quite small, being only 2.5 millimetres (0.098 in) in body length, with the tail being about 3 millimetres (0.12 in) 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.
Pachyballus miniscutulus is a species of jumping spider that is native to Ivory Coast and South Africa. It lives in open grassland and in vegetation near to streams. A very small spider, it has a cephalothorax that is ranges from 1 to 1.3 mm long and an abdomen that is between 1.7 and 1.9 mm long. The spider is generally dark brown on top. The bottom of its cephalothorax is yellowish-brown and its abdomen is grey-brown and has a distinctive scutum. This scutum is referenced in the species name, which is derived from the Latin words that mean "small shield". The spider has a dark brown clypeus and yellowish-brown spinnerets. Apart from the scutum, the spider can be identified by its copulatory organs. The male has a palpal bulb that has bulges that extend below its cymbium and the female has a heart-shaped epigyne that contains a spade-like or circular section and longer insemination ducts than Pachyballus mombasensis. A member of the genus Pachyballus, the species was first described in 2020 by Wanda Wesołowska, Galina Azarkina and Konrad Wiśniewski.
Pochyta aurantiaca is a species of jumping spider in the genus Pochyta that lives in Gabon. A small spider, it was first described in 2021 by Wanda Wesołowska and Tamás Szűts. It has an oval cephalothorax that is between 1.8 and 2.8 mm long and an ovoid abdomen, between 1.8 and 2.4 mm long. The female is lighter than the male and has a narrower abdomen. The spider has a generally yellow to light brown carapace and a yellowish abdomen, but the female specimens have patterns that can include black, reddish-orange and reddish patches. All the spiders have light yellow spinnerets. The front pair of legs are longer than the others and have brown spines. The spider has unique copulatory organs, with the male having a clump of long dense hairs around its small projection on the palpal tibia, called a tibial apophysis, and the female having sclerotized hoods around the copulatory openings on its epigyne.
Pochyta equatorialis is a species of jumping spider in the genus Pochyta that lives in Gabon and Uganda. A small spider, it has an oval cephalothorax that is between 1.9 and 2.3 mm long and an ovoid abdomen, between 1.9 and 2.4 mm long. The female is lighter than the male and has a smaller carapace. The female also has lighter spinnerets and legs. All the spiders have a darker eye field, which have a scattering bristles. The spider has distinctive copulatory organs, although the female is similar to the related Pochyta maddisoni. The male has a distinctive clump of long hairs on its palpal tibia, a blunt apophysis and an irregularly-shaped palpal bulb. The species was first described in 2021 by Wanda Wesołowska and Tamás Szűts and is named for its equatorial distribution.
Pochyta konilokho is a species of jumping spider in the genus Pochyta that is endemic to Guinea. A small spider, it was first described in 2021 by Wanda Wesołowska and Tamás Szűts. It has a generally yellowish with a cephalothorax that is typically 2.1 mm long and an abdomen that is typically 1,8 mm long. The spider's spinnerets are also yellow as are its pedipalps. Its legs are lighter, a whitish-yellowish, and have brown hairs as well as the spines that are common on the legs of spiders in the genus. The spider is hard to distinguish from others in the genus. The male has distinctive copulatory organs, especially the shape of its tibial apophysis. The female has not been described.
Pochyta tendicula is a species of jumping spider in the genus Pochyta that lives in Gabon. A small spider, it was first described in 2021 by Wanda Wesołowska and Tamás Szűts. It has a light brown oval cephalothorax that is typically 2.4 mm long and has eyes that are surrounded by dark rings. It has an ovoid abdomen, typically 2.2 mm long, that is generally greyish-beige on top and grey underneath. Its front pair of legs are longer than the others and marked with long spines. The male has distinctive copulatory organs, with a long embolus that projects from a small palpal bulb, and a small curved spike in the palpal tibia called a retrolateral tibial apophysis. The female has not been described.
