| Hemigrapsus | |
|---|---|
 | |
| Hemigrapsus nudus | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Family: | Varunidae |
| Subfamily: | Varuninae |
| Genus: | Hemigrapsus Dana, 1851 |
| Type species | |
| Hemigrapsus crassimanus Dana, 1851 | |
Hemigrapsus is a genus of varunid crabs comprising thirteen species native almost exclusively in the Pacific Ocean, but two have been introduced to the North Atlantic region.
The natural range of the genus is restricted to the Pacific Ocean, except for Hemigrapsus affinis which lives along the Atlantic coasts of South America, from Cape São Roque (Rio Grande do Norte state, Brazil) to the San Matías Gulf, (Patagonia, Argentina). H. estellinensis is almost certainly extinct, but was endemic to a hypersaline spring in the Texas Panhandle, 500 mi (800 km) from the sea. [1] Populations of Hemigrapsus sanguineus have been introduced from the species' native range in East Asia to several places, and now range along the Atlantic coast of North American from Portland, Maine to North Carolina, along the West European coast from northern Spain to Denmark, and in the northern Adriatic Sea and northern Black Sea. [2] [3] [4] [5] H. takanoi is native to East Asia, but has been introduced to western Europe, now extending from northern Spain to Denmark, including the westernmost Baltic Sea area. [6] [7]
Fifteen species are currently recognised: [8]
The Decapoda or decapods are an order of crustaceans within the class Malacostraca, including many familiar groups, including crabs, lobsters, crayfish, shrimp, and prawns. Most decapods are scavengers. The order is estimated to contain nearly 15,000 species in around 2,700 genera, with around 3,300 fossil species. Nearly half of these species are crabs, with the shrimp and Anomura including hermit crabs, porcelain crabs, squat lobsters making up the bulk of the remainder. The earliest fossils of the group date to the Devonian.
Xanthidae is a family of crabs known as gorilla crabs, mud crabs, pebble crabs or rubble crabs. Xanthid crabs are often brightly coloured and are highly poisonous, containing toxins which are not destroyed by cooking and for which no antidote is known. The toxins are similar to the tetrodotoxin and saxitoxin produced by puffer fish, and may be produced by bacteria in the genus Vibrio living in symbiosis with the crabs, mostly V. alginolyticus and V. parahaemolyticus.
Portunidae is a family of crabs which contains the swimming crabs. Its members include many well-known shoreline crabs, such as the blue crab and velvet crab. Two genera in the family are contrastingly named Scylla and Charybdis; the former contains the economically important species black crab and Scylla paramamosain.
Tuerkayana hirtipes is a species of terrestrial crab.
The Grapsidae are a family of crabs known variously as marsh crabs, shore crabs, or talon crabs. The family has not been confirmed to form a monophyletic group and some taxa may belong in other families. They are found along the shore among rocks, in estuaries, marshes, and in some cases pelagic among drifting seaweeds and flotsam.
Macrophthalmus is a genus of crabs which are widespread across the Indo-Pacific. It contains the following species :
Hemigrapsus sexdentatus, also called the “common rock crab” or “common shore crab,” is a marine crab indigenous to the southern shores of New Zealand. This crab is a member of the Varunidae family in the order Decapoda.
Hemigrapsus crenulatus, the hairy-handed crab or papaka huruhuru, is a marine crab of the family Varunidae, endemic to the New Zealand coast, although a taxon in Chile may be conspecific. It is an intertidal species with semi-terrestrial tendencies. They are named by their characteristic setae, or patches of thick hair, on the chelipeds and legs. They can range from green to brown in coloration. Adult crabs are generally 2–4 cm (0.8–1.6 in) wide at the carapace, although the smallest mature crabs can be around just 1 cm (0.4 in) wide. and are able to survive and reproduce in environments of widely varying salinities.
Charybdis is a genus of swimming crabs in the family Portunidae. It is named after the monster Charybdis of Greek mythology.
Hemigrapsus sanguineus, the Japanese shore crab or Asian shore crab, is a species of crab from East Asia. It has been introduced to several other regions, and is now an invasive species in North America and Europe. It was introduced to these regions by ships from Asia emptying their ballast tanks in coastal waters.
The Gecarcinidae, the land crabs, are a family of true crabs that are adapted for terrestrial existence. Similar to all other crabs, land crabs possess a series of gills. In addition, the part of the carapace covering the gills is inflated and equipped with blood vessels. These organs extract oxygen from the air, analogous to the vertebrate lungs. Adult land crabs are terrestrial, but visit the sea periodically, where they breed and their larvae develop. Land crabs are tropical omnivores which sometimes cause considerable damage to crops. Most land crabs have one of their claws larger than the other.
The Sesarmidae are a family of crabs, previously included in the Grapsidae by many authors. Several species, namely in Geosesarma, Metopaulias, and Sesarma, are true terrestrial crabs. They do not need to return to the sea even for breeding.
The Varunidae are a family of thoracotrematan crabs. The delimitation of this family, part of the taxonomically confusing Grapsoidea, is undergoing revision. For a long time, they were placed at the rank of subfamily in the Grapsidae, but they appear to be closest to Macropthalmus and the Mictyridae, which are usually placed in the Ocypodoidea. It may thus be better to merge the latter superfamily with the Grapsoidea, retaining the latter name as it is older.
Hemigrapsus takanoi, the brush-clawed shore crab or Asian shore crab, is a small crab of the family Varunidae that lives on rocky shores surrounding the Pacific Ocean, and which is invasive along the European coastlines. This crab is omnivorous and eats small fish, invertebrates and algae.
Pilumnoidea is a superfamily of crabs, whose members were previously included in the Xanthoidea. The three families are unified by the free articulation of all the segments of the male crab's abdomen and by the form of the gonopods. The earliest fossils assigned to this group are of Eocene age.
Hemigrapsus estellinensis is an extinct species of crab, formerly endemic to the Texas Panhandle. It was discovered by Gordon C. Creel in 1962 and was probably already extinct before his description was published in 1964, after the Estelline Salt Springs where it lived were contained by the United States Army Corps of Engineers. H. estellinensis is closely related to species from the Pacific Ocean such as Hemigrapsus oregonensis, but lived 800 km (500 mi) inland in a hypersaline spring. It differed from its relatives by the pattern of spots on its back, and by the relative sizes of its limbs.
Hemigrapsus penicillatus is a species of crab. The native range of Hemigrapsus penicillatus extends from the Russian Far East along the coasts of Japan, China, Taiwan and Korea, as far south-west as Hong Kong. Although the species was reported from Hawaii in 1903, this is likely to have been an error; there are no recent records of the species in the central Pacific. Reports of H. penicillatus on the coasts of Europe refer to a related species, H. takanoi, which was only distinguished from H. penicillatus in 2005, several years after its discovery in Europe. Hemigrapsus penicillatus lives in the intertidal zone on stony or muddy shores.
Polyascus is a genus of barnacles in infraclass Rhizocephala. It was circumscribed in 2003 by Henrik Glenner, Jørgen Lützen, and Tohru Takahashi. They included three species, all transferred from Sacculina. The generic name polyascus refers to the typical presence of multiple external sac-like female bodies, known as externae. In Polyascus species, these originate from asexual reproduction.
Austruca is a genus of indo-west Pacific fiddler crabs in the family Ocypodidae. There are about 13 described species in this genus.
Media related to Hemigrapsus at Wikimedia Commons
Data related to Hemigrapsus at Wikispecies| Authority control databases: National |
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