Sea spiders are marine arthropods of the order Pantopoda, belonging to the class Pycnogonida, hence they are also called pycnogonids. They are cosmopolitan, found in oceans around the world. The over 1,300 known species have leg spans ranging from 1 mm (0.04 in) to over 70 cm (2.3 ft). Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters.
Colossendeidae is a family of sea spiders. This family includes more than 100 species distributed among six genera. These sea spiders inhabit the deep sea mostly but are also found in shallower waters, especially in Antarctic and Arctic waters.
Camposaurus is a coelophysid dinosaur genus from the Norian stage of the Late Triassic period of North America. The pertinent fossil remains date back to the early to middle Norian stage, and is widely regarded as the oldest known neotheropod.
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa, trochanter, femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus, patella.
Nymphonidae is a family of sea spiders which has representatives in all the oceans. This family contains some 250 species, most of which are found in the genus Nymphon. Nymphonid bodies are between 1 and 15 mm long, the extent between the points of the legs reaching 150 mm. Most species are predators of hydroids. Like most sea spiders, species in this family have four pairs of legs, except for Pentanymphon antarcticum, which has five pairs, and Sexanymphon mirabilis, which has six pairs.
The mouthparts of arthropods have evolved into a number of forms, each adapted to a different style or mode of feeding. Most mouthparts represent modified, paired appendages, which in ancestral forms would have appeared more like legs than mouthparts. In general, arthropods have mouthparts for cutting, chewing, piercing, sucking, shredding, siphoning, and filtering. This article outlines the basic elements of four arthropod groups: insects, myriapods, crustaceans and chelicerates. Insects are used as the model, with the novel mouthparts of the other groups introduced in turn. Insects are not, however, the ancestral form of the other arthropods discussed here.
Pycnogonidae is a family of sea spiders.
Pycnogonum is a genus of sea spiders in the family Pycnogonidae. It is the type genus of the family.
Nymphon brevirostre is a species of sea spider first described by George Hodge in 1863. The species highly resembles other members of the genus Nymphon, and species identification from morphological traits alone is therefore a complex task.
Nymphon gracile is a species of sea spider first described by William Elford Leach in 1863. The species highly resembles other members of the genus Nymphon, and species identification from morphological traits alone is, therefore, a complex task.
Colossendeis is a genus of sea spider belonging to the family Colossendeidae. These sea spiders are typically found in the deep sea. This genus includes the largest pycnogonids, with leg spans ranging from 40 to 50 centimeters. This genus also includes some bioluminescent sea spiders.
Pseudomogrus mirandus is a species of jumping spider in the genus Pseudomogrus. It has been found in Turkmenistan on the steppe, although it may also live in Afghanistan and Iran. The species was first defined by Wanda Wesołowska in 1991, one of over 500 described by the arachnologist. She originally placed it in the genus Yllenus, but was moved to the new genus Logunyllus in 2016, and then to its present designation in 2019. The spider is small, with a carapace measuring between 1.6 and 1.78 mm long and an abdomen between 1.4 and 2.3 mm long. The male has a red-brown or dark brown carapace and dark grey abdomen, the female a brown carapace and greyish-brown abdomen. All have a covering of small white scales. The spider has yellow legs. The copulatory organs are distinctive and enable the spider to be distinguished from others in the genus. The female epigyne has a half-moon-shaped pocket and simple insemination ducts that lead to spherical spermathecae. The male lacks the ventral tibial apophysis common in other species and has a compound terminal apophysis that is of a similar length to its thin embolus.
Palaeoisopus is a monotypic genus of fossil pycnogonid, known only by one species, Palaeoisopus problematicus, discovered from the Lower Devonian Hunsrück Slate of Germany. It have several characters unusual for a pycnogonid, such as swimming legs with alternating size, medially-arranged eyes, and most significantly, a long, segmented abdomen, which were highly reduced in modern counterparts.
Colossendeis colossea is a species of sea spider in the family Colossendeidae. The species was first described by Edmund B. Wilson in 1881. It is the largest pycnogonid species known to science, reaching a leg span of 70 cm (28 in). Body length, including proboscis and abdomen, can reach 7 cm (2.8 in).
Detalik is a genus of jumping spiders, consisting of four species. The genus was circumscribed in 2021 by Wanda Wesołowska, along with descriptions of the type species Detalik anthonyi and two other species. These were all found in Nigeria, although another species described in 2022 lives in Ivory Coast. Generally, the members of the genus are very small spiders, between 3.5 and 5 mm long. They have distinctive features in their mouthparts, including a short fang on their jaws, or chelicerae, along with a two small teeth to the front and a large tooth to the back. The upper part of their body, the carapace, is noticeable for its almost vertical sloping back and the front legs are characterised with very long spikes on the tibia and metatarsus. While each species has unique reproductive organs, there are some common features: males have a spike at the back of a structure used during mating while females have their reproductive openings hidden in a small indentation in the visible part of their copulatory organs, the epigyne.
Prosotherium is an extinct genus of late Oligocene hegetotheriid notoungulate. It has been found in two Argentinian fossil formations, ie, the Sarmiento Formation in Chubut Province, and the Agua de la Piedra Formation in Mendoza Province.
Pochyta lucida 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 2.3 mm long and an ovoid abdomen that is 2.8 mm long. It is generally light, with a yellow carapace and greyish-beige abdomen, which is recalled in the species name, which can be translated "light". The spider's eye field is orange and there are dark rings around the eyes themselves. It has yellow legs, the front pair having extremely long spines as is typical for the genus. The female has distinctive copulatory organs, with a noticeable ridge in the middle of its epigyne and short insemination ducts. The male has not been described.
Decolopoda is a genus of sea spider belonging to the family Colossendeidae. This genus includes two valid species, D. australis and D. qasimi. As the name of this genus implies, these two species are among the seven species of sea spider with five pairs of legs instead of the usual four leg pairs. The species D. australis is notable as the first polymerous sea spider to be discovered.
Flagellopantopus is an extinct genus of pycnogonid arthropod known from the lower Devonian aged Hunsrück Slate. A single species is currently known, Flagellopantopus blocki, which was described from the Emsian aged Kaub Formation in Germany.
