Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers on each arm. They first appeared during the Jurassic period, around 200 million years ago.
Mangrove crabs are crabs that live in and around mangroves. They belong to many different species and families and have been shown to be ecologically significant by burying and consuming leaf litter. Mangrove crabs have a variety of phylogenies because mangrove crab is an umbrella term that encompasses many species of crabs. Two of the most common families are sesarmid and fiddler crabs. They are omnivorous and are predated on by a variety of mammals and fish. They are distributed widely throughout the globe on coasts where mangroves are located. Mangrove crabs have wide variety of ecological and biogeochemical impacts due to the biofilms that live in symbiosis with them as well as their burrowing habits. Like many other crustaceans, they are also a human food source and have been impacted by humans as well as climate change.
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.
Leptograpsus variegatus, known as the purple rock crab, is a marine large-eyed crab of the family Grapsidae, found in southern subtropical Indo-Pacific Oceans. It grows to around 50 millimetres (2.0 in) shell width. It is the only species in the genus Leptograpsus.
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 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.
Sesarma is a genus of terrestrial crabs endemic to the Americas.
Latreilliidae is a small family of crabs. They are relatively small, long-legged crabs found on soft bottoms at depths of up 700 metres (2,300 ft) in mostly tropical and subtemperate waters around the world. Their carapace is very small and doesn’t cover the bases of their legs, which protrude from the cephalothorax in a spider-like manner. The family and its type genus are named after Pierre André Latreille. The oldest known fossils from the Latreillidae have been dated to the middle of the Cretaceous period. It comprises seven extant species.
Minuca pugnax, commonly known as the Atlantic marsh fiddler crab, is a species of fiddler crab that lives on north-western shores of the Atlantic Ocean.
Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow. The larvae of crustaceans often bear little resemblance to the adult, and there are still cases where it is not known what larvae will grow into what adults. This is especially true of crustaceans which live as benthic adults, more-so than where the larvae are planktonic, and thereby easily caught.
Karstarma is a genus of karst-dwelling crabs formerly included in Sesarmoides.
Parasesarma leptosoma, also known as the arboreal crab, is an arboreal, leaf-eating mangrove crab, from East and South Africa where it is found on Rhizophora mucronata and Bruguiera gymnorhiza, but not on Avicennia marina. It occupies an ecological niche similar to that of another sesarmid, Aratus pisonii, from the Americas.
Geosesarma dennerle is a species of small land-living crabs found on Java, Indonesia.
Neosarmatium smithi, is a swimming crab species in the genus Neosarmatium. Distributed all over marine and brackish waters of Indo-West Pacific regions.
The Micro Mangrove Crab (Haberma tingkok) is a species of micro-mangrove crab native to Hong Kong. It was first discovered by Stefano Cannicci from the University of Hong Kong and Peter Ng from the University of Singapore in the Ting Kok Mangrove forests in the northeast of Hong Kong and listed on the World Register of Marine Species (WoRMS) in April 2017. It was the third species placed in the genus Haberma, which was described in 2002.
Armases is a genus of true crabs in the family Sesarmidae. There are about 13 described species in Armases.
Hepatus pudibundus, the flecked box crab, is a crab from the class Malacostraca. They are found in the Atlantic Ocean with Brazil having a dense population of H. pudibundus, as they are one of the most commonly seen crabs in the country. Many of the studies done on H. pudibubus have occurred in the Ubatuba region of Brazil, where there is a rapid expansion of tourism that is affecting marine ecosystems.
Parasesarma messa, commonly known as the maroon mangrove crab, is a species of burrowing crab found in Queensland, Australia. It lives in mangroves in estuaries and sheltered bays. It was originally described as Sesarma messa, but was placed in the genus Parasesarma in 2017. Perisesarma messa is also a synonym.
Sesarmops is a genus of crabs in the family Sesarmidae. Its members are distributed through the Indo–West-Pacific oceanic region. They live in freshwater forest streams near the coast, and in mangroves.
