Dodecolopoda | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Pycnogonida |
Order: | Pantopoda |
Family: | Colossendeidae |
Genus: | Dodecolopoda Calman & Gordon, 1933 |
Species: | D. mawsoni |
Binomial name | |
Dodecolopoda mawsoni Calman & Gordon, 1933 | |
Dodecolopoda is a monotypic genus of sea spider (class Pycnogonida) in the family Colossendeidae. [1] The only species in this genus is Dodecolopoda mawsoni. [1] This species is notable as one of only two species of sea spider with six pairs of legs (instead of the usual four leg pairs) and the first such species to be discovered. [2] [3]
This species was first described by the Scottish zoologists William Thomas Calman and Isabella Gordon of the British Museum (Natural History) in 1933. The original description is based on a male holotype found at a depth of 219 meters below the surface off the coast of MacRobertson Land. Calman and Gordon named this species for Sir Douglas Mawson, who obtained this specimen on his voyage to the Antarctic region in 1931. [4]
This sea spider is notable for not only its twelve legs but also its gigantic size, measuring 20 inches (510 mm) from tip to tip of its legs when fully extended. [4] The leg of the fourth pair on the holotype, for example, measures 240.3 millimetres (9.46 in) in length. [4] The sea spider's long legs act as stilts, holding its body well above the seabed surface below. [5] This species is the only sea spider to combine giant size with six pairs of legs, as the only other species with twelve legs (Sexanymphon mirabilis) is small. [6]
The twelve-legged sea spiders in the genus Dodecolopoda resemble the ten-legged species in the genus Decolopoda . For example, both genera feature long legs, a long proboscis that curves downward and is distally inflated, and a tarsus (third most distal article of the leg) that is much longer than the propodus (second most distal leg article). [6] The sea spiders in Dodecolopoda, however, are larger, feature a longer tarsus and shorter claw (most distal leg article) compared to the propodus, and have more legs than the species in Decolopoda. [4]
Both Dodecolopoda and Decolopoda resemble the eight-legged species in the genus Colossendeis (e.g., C. wilsoni) but retain chelifores as adults. [3] Phylogenetic analysis based on molecular data indicates that both Dodecolopoda and Decolopoda are nested within the genus Colossendeis in a phylogenetic tree. Thus, Colossendeis is paraphyletic with respect to these two polymerous (i.e., extra-legged) genera. This paraphyly would normally make both Dodecolopoda and Colossendeis junior synonyms of Decolopoda, the oldest name, and require all three genera to merge under the name Decolopoda. To avoid this disruption, authorities keep these genera under different names and retain Colossendeis as a paraphyletic genus. [7]
This sea spider is found in the Indian and Atlantic regions of the Southern Ocean and is endemic to the Antarctic region. [8] [9] Specimens have been found off the South Shetland Islands, the Palmer Archipelago, and Enderby Land, and in the Ross Sea, captured at depths ranging from 146 to 549 meters below the surface. The distribution of this species is probably circumpolar. [6]
Malacostraca is the second largest of the six classes of pancrustaceans just behind hexapods, containing about 40,000 living species, divided among 16 orders. Its members, the malacostracans, display a great diversity of body forms and include crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, amphipods, mantis shrimp, tongue-eating lice and many other less familiar animals. They are abundant in all marine environments and have colonised freshwater and terrestrial habitats. They are segmented animals, united by a common body plan comprising 20 body segments, and divided into a head, thorax, and abdomen.
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.
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.
Nymphon is a genus of sea spiders in the family Nymphonidae. The species of sea spiders within the genus Nymphon are all benthic organisms and are found in abyssal and bathyal areas of the ocean. This is a fully marine group and can be found at various depths ranging from the littoral zones to the deep sea. They are found in most major oceans across the globe with a strong distribution around polar regions: Arctic and Antarctic waters. Out of the sea spider genus, Nymphon is the most rich, with a majority of the species within the genis being found in the Southern Ocean region. This genus may also contain bioluminescent species.
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 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. Phylogenetic analysis based on molecular data indicates that this genus is paraphyletic with respect to the genera Decolopoda and Dodecolopoda, which are found to be nested within the genus Colossendeis in a phylogenetic tree.
Thiratoscirtus alveolus is a species of jumping spider in the genus Thiratoscirtus that lives in Nigeria. The species was first described in 2011 by Wanda Wesołowska and Russell-Smith. The holotype was found on Obudu Plateau, Cross River State at an altitude of 1,900 m (6,200 ft) above sea level. The spider is medium-sized, with a cephalothorax that is typically 2.8 mm long and an abdomen that is 2.8 mm in length. The body of the female is generally brown with a covering of delicate hairs. The mouthparts include powerful chelicerae with teeth that have multiple points and a short fang. It can be distinguished from other spiders in the genus by its copulatory organs, particularly the presence of two long and deep parallel troughs in the epigyne that lead to the gonopores. These are recalled in the name for the species, which can be translated "trough".
Callipallene is a genus of sea spiders in the family Callipallenidae. There are more than 30 described species in Callipallene.
Halonoproctidae is a family of mygalomorph spiders, split off from the family Ctenizidae in 2018. Species in the family are widely distributed in North and Central America, Australasia, Asia, southern Europe and North Africa. One species is recorded from Venezuela in South America. They are relatively large, sombrely coloured spiders, that live in burrows with some kind of trapdoor.
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).
Propallene longiceps is a species of sea spider in the family Callipallenidae. It is found in shallow water in the western Pacific Ocean.
Colossendeis proboscidea is a species of sea spider in the family Colossendeidae. It is native to the Arctic and northeast Atlantic.
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.