| Neolithodes | |
|---|---|
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| Neolithodes crab at the Davidson Seamount off California | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Anomura |
| Family: | Lithodidae |
| Subfamily: | Lithodinae |
| Genus: | Neolithodes A. Milne-Edwards & Bouvier, 1894 |
| Type species | |
| Neolithodes grimaldii (A. Milne-Edwards & Bouvier, 1894) | |
Neolithodes is a genus of king crabs in the subfamily Lithodinae. [1]
Neolithodes has a pyriform carapace which does not cover the bases of its walking legs. [2] Of its three pairs of walking legs, the rearmost are the longest, and all of them have a similar form. [3] At the very front center of the carapace, its rostrum consists of a median spine and a pair of upward-slanted (dorsal) spines. [3] Behind the rostrum sits the elevated gastric region, followed by a deep groove separating it from the triangular cardiac region. [3] The cervical groove behind that is shallow and indistinct. [3] When measuring the carapace's length without including the rostrum, [a] the carapace is always shorter than the walking legs. [3]
Its second abdominal segment consists of five plates: a median plate and paired submedian and marginal (outer) plates. [3] As in all king crabs, males have a symmetrical abdomen, but females' abdomens are skewed – enlarged on the left side and reduced on the right. [5] In males, the third through fifth abdominal segments are composed of spine-like nodules, while in females, these are composed of well-developed plates on the left and well-developed plates or simply spine-like nodules on the right. [3] In front of the abdomen is a deep, logitudinal sternal fissure between the frontmost pair of walking legs; [3] this fissure is also present in Lithodes and readily distinguishes the two genera from other king crabs. [6]
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). [7] [8] [9] Neolithodes grimaldii has been reported to a depth of 5,238 m (17,185 ft). [10]
Various sessile organisms such as barnacles are sometimes attached to their carapace and legs, [10] [11] and small commensal amphipods may live in their carapace. [12] They are occasionally the victims of parasitic snailfish of the genus Careproctus , which lay their egg mass in the gill chamber of the crab, forming a mobile "home" until they hatch. [7] Conversely, some juvenile Neolithodes have a commensal relationship with Scotoplanes sea cucumbers. To protect itself from large predators, the young king crab hides under the sea cucumber. [13]
Neolithodes was described in 1894 by carcinologists Alphonse Milne-Edwards and Eugène Louis Bouvier. [14] They initially placed the new species they found, Neolithodes grimaldii , in the closely related genus Lithodes , but they shortly thereafter constructed the genus Neolithodes based on the new species' distinctive abdomen, which they compared to the monotypic genus Dermaturus . [14] The word Neolithodes derives from the Greek neo, meaning "new", and Lithodes. [15] The name of the latter genus originates from the Latin lithodes, meaning "stone-like". [15] No known Neolithodes fossils exist. [16] Neolithodes' relationship to other king crabs can be seen in the following cladogram: [17]
Lithodidae cladogram |
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Neolithodes contains the following species: [1]
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Media related to Neolithodes at Wikimedia Commons
Data related to Neolithodes at Wikispecies
