| 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]
| Authority control databases: National |
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