| Paralomis | |
|---|---|
 | |
| Paralomis granulosa | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Anomura |
| Family: | Lithodidae |
| Subfamily: | Lithodinae |
| Genus: | Paralomis White, 1856 [1] |
| Type species | |
| Paralomis granulosa (Hombron & Jacquinot, 1846) | |
| Synonyms [2] | |
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Paralomis is a widely distributed, highly speciose, and morphologically diverse genus of king crabs in the subfamily Lithodinae. [2] [3]
Like all king crabs, Paralomis has evolved a crab-like appearance through a process called carcinisation. [3] Paralomis has either a pentagonal or pyriform carapace. [3] At the very front, its rostrum consists of one short, conical spine projecting forward in the middle and one or more pairs of spines angled upward around the base. [3] [4] Like all king crabs, the gastric region, directly behind the rostrum, is elevated above the others. [3] Like Lithodes and Neolithodes , the cardiac region – directly behind the gastric region, separated by a deep groove – is triangular. [3] Its three pairs of walking legs – morphologically similar, with the middle pair typically being the longest – are not covered at their bases by the carapace. [3] In adults, the undersides of the dactyli feature horn-like spines. [3] The abdomen is more calcified than in other king crab genera: the second segment is undivided, the third segment has fused submedian and marginal (outer) plates, and segments three, four, and five are all entirely calcified. [3]
Paralomis is present in four of Earth's five oceans – namely the Atlantic, Pacific, Indian, and Southern – as well as all seven continents. [3] They are found from the very shallow intertidal zone to the deep, perpetually dark abyssal zone. [4] The deepest known species of Paralomis is P. bouvieri , which has been discovered living at 4,152 m (13,622 ft). [3]
Paralomis was described in 1856 by zoologist Adam White and named for its similarity to the genus Lomis . [1] In 1895, marine biologist James Everard Benedict incorrectly placed Paralomis granulosa , the genus' type species, under the genus Lithodes . [5] [3] Benedict therefore dissolved the genus and created two now-defunct ones – Leptolithodes and Pristopus – for other members of Paralomis. [5] [3] Paralomis is closely related to Echidnocerus , and the monospecific genus Glyptolithodes – nested cladistically inside Paralomis – may simply be a species of Paralomis. [6] [7] [8]
Paralomis contains over 70 species – more than any other king crab genus – and is the most morphologically diverse genus in the subfamily Lithodinae. [3] [4] It contains one fossil species, Paralomis debodeorum , which lived in New Zealand in the Middle–Late Miocene. [3] Paralomis is distinguished from other king crabs by its abdominal segments: the second is undivided, and the third, fourth, and fifth are entirely calcified. [3] Current scientific consensus is that Paralomis is monophyletic, although within this group, carcinologist Shane T. Ahyong in 2010 identified several informal subgroups of Paralomis. [3] Paralomis' relationship to other king crabs can be seen in the following cladogram: [6]
Lithodidae cladogram |
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Paralomis contains the following species: [2]
King crabs are decapod crustaceans of the family Lithodidae that are chiefly found in deep waters and are adapted to cold environments. They are composed of two subfamilies: Lithodinae, which tend to inhabit deep waters, are globally distributed, and comprise the majority of the family's species diversity; and Hapalogastrinae, which are endemic to the North Pacific and inhabit exclusively shallow waters. King crabs superficially resemble true crabs but are generally understood to be closest to the pagurid hermit crabs. This placement of king crabs among the hermit crabs is supported by several anatomical peculiarities which are present only in king crabs and hermit crabs, making them a prominent example of carcinisation among decapods. Several species of king crabs, especially in Alaskan and southern South American waters, are targeted by commercial fisheries and have been subject to overfishing.
Anomura is a group of decapod crustaceans, including hermit crabs and others. Although the names of many anomurans include the word crab, all true crabs are in the sister group to the Anomura, the Brachyura.
Lithodes is a genus of king crabs. Today there are about 30 recognized species, but others formerly included in this genus have been moved to Neolithodes and Paralomis. They are found in oceans around the world, ranging from shallow to deep waters, but mostly at depths of 100–1,000 m (300–3,300 ft). They are restricted to relatively cold waters, meaning that they only occur at high depths at low latitudes, but some species also shallower at high latitudes. They are medium to large crabs, and some species are or were targeted by fisheries.
Neolithodes is a genus of king crabs in the subfamily Lithodinae. They are found in all major oceans, both in high and low latitudes. Although there are records from water as shallow as 70 m (230 ft) in cold regions, most records are much deeper, typically 700–2,000 m (2,300–6,600 ft), with the deepest confirmed at 5,238 m (17,185 ft). They are fairly large to large crabs that typically are reddish in color and spiny, although the size of these spines varies depending on species.
Paralomis zealandica, also known as the prickly king crab, is a species of king crab which lives at a depth between 254–1,212 m (833–3,976 ft) in New Zealand. It has a spiky carapace.
Neolithodes agassizii is a species of king crab native to the Western Atlantic. They live at depths of 200–1,900 metres (660–6,230 ft), and have been found as far south as Rio de Janeiro, as far north as latitude 36°, and near the Equator. It has been found in the southwestern Caribbean Sea as well as the Gulf of Mexico.
Neolithodes yaldwyni is a species of king crab which is found in the Ross Sea from depths of 124–1,950 metres (407–6,398 ft). It had previously been misidentified as Neolithodes brodiei, and it closely resembles Neolithodes capensis.
Neolithodes capensis is a species of king crab which is found in the Southern Ocean and the western Indian Ocean. It has been found to a depth of 660–3,200 metres (2,170–10,500 ft). They have been found near Cape Point and around the Crozet and Kerguelen Islands in the subantarctic, and they are widespread in the Bellingshausen Sea on the Antarctic continental slope.
Neolithodes diomedeae is a species of king crab which is found in the eastern Pacific Ocean, the southwestern Atlantic Ocean, and the Bellingshausen and Scotia Seas in the Southern Ocean. They occur from 200 to 2,454 m.
Neolithodes nipponensis is a species of king crab which is found in Japan and Taiwan. It has been found at depths from 200–1,752 metres (656–5,748 ft).
Paralomis dawsoni is a species of king crab which lives in New Caledonia, northern New Zealand, and the Solomon Islands at depths of 400–1,118 m (1,312–3,668 ft). Alongside P. zealandica, it is one of the two most common species of Paralomis in New Zealand. As of 2023, the Department of Conservation in New Zealand classifies P. dawsoni as "Naturally Uncommon".
Lithodes aotearoa is a New Zealand species of king crab. It had formerly been confused with L. longispina and L. murrayi, but neither of those species are found in New Zealand. It is the second most widespread and common lithodid in New Zealand waters after Neolithodes brodiei, and the New Zealand Department of Conservation classifies it as "Not Threatened".
Lithodes jessica is a species of king crab in the genus Lithodes. It is found off the coast of New Zealand on the Lord Howe Rise at depths from 680–1,100 m (2,230–3,610 ft).
Lithodes macquariae is a species of king crab located off Macquarie Island, the Auckland Islands, and Peter I Island. It has been found at depths of 16–1,140 m (52–3,740 ft).
Paralomis okitoriensis is a species of king crab. It has been identified near Japan's southernmost atoll, Okinotorishima.
Lithodes unicornis is a species of king crab. It lives at the muddy bottoms of an oceanic plateau in the southern Atlantic Ocean's Walvis Ridge known as the Valdivia Bank, residing at a depth of about 935 m (3,068 ft).
Paralomis granulosa, also known as the false king crab, the Chilean snow crab, and centollón (Spanish), is a species of king crab. It lives around the southern tip of South America in Chile, Argentina, and the Falkland Islands. It is smaller than Lithodes santolla – a sympatric species of king crab – having a carapace length up to 115 mm (4.5 in), and weighing up to 1.5 kg (3.3 lb).
Lithodes australiensis is a species of king crab. They live in southeastern Australia, known as far north as Cape Hawke and as far south as the South Tasman Rise. They have been found at depths between 540–1,312 m (1,772–4,304 ft), but they typically live between 1,000–1,100 m (3,300–3,600 ft).
Lithodes robertsoni is a species of king crab. It has been found in New Zealand at depths between 935–1,259 m (3,068–4,131 ft). It is distributed from as far north as the Challenger Plateau to as far south as the Snares Islands. The largest yet-examined specimen is its male holotype whose carapace measures 128.1 mm (5.04 in) in postrostral length and 117.0 mm (4.61 in) in width.
| Authority control databases: National |
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