Nematocarcinus, sometimes known as spider shrimp, is a genus of caridean shrimp, the nominotype of Nematocarcinidae. Similar to the other members of their family, Nematocarcinus inhabit the deep sea, walking on the seabed with their specialized, extremely elongate legs (the pereiopods). Despite continuing fisheries experiments, they are currently not commercially fished, but often appear as bycatch.
Description Nematocarcinus has a number of diagnostic characters, such as the shape and teeth of the rostrum, the shape of the third abdominal tergite, the shape of the fifth abdominal pleura along with short protuberances or a ridge on the inner surface of its anterior margin, the accessory teeth of the telson, and the ventral margin of the sixth abdominal somite (the distoventral organ) along with its associated setae. Another notable trait is their "mud shoes"; the long and slender pereopods possess tufts of long setae at the dactyls, which presumably helps distribute their weight over the pelagic sediment. In general, the bodies of these shrimp are rather delicate, and specimens are often damaged when collected by traditional methods such as trawling.
These shrimp are inhabitants of the deep sea, with some species living at over deep,Gulf of Mexico 2018: Image and Video Gallery and up to deep on the abyssal plains.Burukovsky, R.N. (2012) Deep sea shrimps of the family Nematocarcinidae (history of study, systematic, distribution, and biology). Prospekt nauki. St. Petersburg, 287 pp. [In Russian with English abstract] They may sometimes occur around hydrothermal vents.Komai, T. & Collins, P. (2009) Two species of caridean shrimps (Decapoda: Hippolytidae and Nematocarcinidae) newly recorded from hydrothermal vents on the Manus Basin, southwestern Pacific. Crustacean Research, 38, 28–41. In some regions, such as the Pacific Coast of Mexico, Nematocarcinus may be locally abundant; up to 500 shrimp per hectare. Members of this genus are very tolerant of hypoxic conditions (low dissolved oxygen content). Other than the Americas, Nematocarcinus is also known from the southern Indian Ocean, South-Western Pacific, North-Western Pacific, and the Southern Ocean.
Females may be highly fecund, with records of up to 15500 eggs carried by a female N. ensifer, though species such as N. lanceopes carry only 2400.
Species The following species are considered valid:
Nematocarcinus africanus Crosnier & Forest, 1973 Nematocarcinus agassizii Faxon, 1893 Nematocarcinus bituberculatus Chace, 1986 Nematocarcinus challengeri Burukovsky, 2006 Nematocarcinus combensis Burukovsky, 2000 Nematocarcinus crosnieri Burukovsky, 2000 Nematocarcinus cursor A. Milne-Edwards, 1881 Nematocarcinus ensifer (Smith, 1882) Nematocarcinus evansi Burukovsky, 2000 Nematocarcinus exilis (Spence Bate, 1888) Nematocarcinus faxoni Burukovsky, 2001 Nematocarcinus gracilipes Filhol, 1884 Nematocarcinus gracilis Spence Bate, 1888 Nematocarcinus hanamuri Burukovsky, 2000 Nematocarcinus kaiensis Burukovsky, 2000 Nematocarcinus lanceopes Spence Bate, 1888 Nematocarcinus longirostris Spence Bate, 1888 Nematocarcinus machaerophorus Burukovsky, 2003 Nematocarcinus manningi Burukovsky, 2003 Nematocarcinus novaezealandicus Burukovsky, 2006 Nematocarcinus nudirostris Burukovsky, 1991 Nematocarcinus parvus Burukovsky, 2000 Nematocarcinus paucidentatus Spence Bate, 1888 Nematocarcinus poupini Burukovsky, 2007 Nematocarcinus productus Spence Bate, 1888 Nematocarcinus proximatus Spence Bate, 1888 Nematocarcinus pseudocursor Burukovsky, 1990 Nematocarcinus pseudogracilis Burukovsky, 2007 Nematocarcinus richeri Burukovsky, 2000 Nematocarcinus romenskyi Burukovsky, 2000 Nematocarcinus rotundus Crosnier & Forest, 1973 Nematocarcinus safari Burukovsky, 2000 Nematocarcinus sigmoideus Macpherson, 1984 Nematocarcinus subtegulisfactus Burukovsky, 2000 Nematocarcinus subtilis Burukovsky, 2000 Nematocarcinus tenuipes Spence Bate, 1888 Nematocarcinus tenuirostris Spence Bate, 1888 Nematocarcinus tuerkayi Burukovsky, 2005 Nematocarcinus undulatipes Spence Bate, 1888 Nematocarcinus webberi Burukovsky, 2006 Nematocarcinus yaldwyni Burukovsky, 2006
References