''Neohelice granulata'' is a species of

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

in the family

Varunidae 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 ap ...

, and the only species in the genus ''Neohelice''. In 2009, it was estimated that ''N. granulata'' was the sixth most studied species of crab.

Distribution and ecology

''Neohelice'' is found in the south-western

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, from the Laguna Araruama in

Rio de Janeiro state Rio de Janeiro () is one of the 27 federative units of Brazil. It has the second largest economy of Brazil, with the largest being that of the state of São Paulo. The state, which has 8.2% of the Brazilian population, is responsible for 9.2% of ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

to the Golfo San José (on the north side of the

Valdes Peninsula The Valdes Peninsula (Spanish: ''Península Valdés'') is a peninsula into the Atlantic Ocean in the Biedma Department of north-east Chubut Province, Argentina. Around in size (not taking into account the isthmus of Carlos Ameghino which connects ...

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

). The diet of ''Neohelice'' in the wild most consists of sediment, ''

Spartina ''Spartina'' is a taxon of plants in the grass family, frequently found in coastal salt marshes. Its species are commonly known as cordgrass or cord-grass, and are native to the coasts of the Atlantic Ocean in western and southern Europe, north ...

'' and plant-derived

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

Taxonomic history

The first report of ''Neohelice'' was probably that made by

Alcide d’Orbigny Alcide Charles Victor Marie Dessalines d'Orbigny (6 September 1802 – 30 June 1857) was a French naturalist who made major contributions in many areas, including zoology (including malacology), palaeontology, geology, archaeology and anthropol ...

during an expedition to South America between 1826 and 1834. He included details of the crab's ecology, including their burrows, but did not name the species. The first person to describe the species taxonomically was

James Dwight Dana James Dwight Dana Royal Society of London, FRS FRSE (February 12, 1813 – April 14, 1895) was an American geologist, mineralogist, volcanologist, and zoologist. He made pioneering studies of mountain-building, volcano, volcanic activity, and the ...

, who named it ''Chasmagnathus granulatus'' in his 1851 work reporting the results of the

United States Exploring Expedition The United States Exploring Expedition of 1838–1842 was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States. The original appointed commanding officer was Commodore Thomas ap Catesby ...

(also known as the "Wilkes expedition"). In 1918,

Mary J. Rathbun Mary Jane Rathbun (June 11, 1860 – April 4, 1943) was an American zoologist who specialized in crustaceans. She worked at the Smithsonian Institution from 1884 until her death. She described more than a thousand new species and subspecies and ...

redescribed the species under the modified name "''Chasmagnathus granulata''", which remained in occasional use along Dana's name until 2006, when Katushi Sakai, Michael Türkay and Si-Liang Yang revised the genera '' Helice'' and ''

Chasmagnathus ''Chasmagnathus convexus'' is a common mud-flat crab of the family (biology), family Varunidae, which is endemism, endemic to East Asia. In Japan, this crab is commonly called ''hamagani''. This crab has two forms that differ in color; one is ol ...

''. They restricted both genera to those species occurring in

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...

, and erected a new genus for ''C. granulatus'', which thus became ''Neohelice granulata'', as well as the genera ''

Austrohelice The tunnelling mud crab, ''Austrohelice crassa'', is a marine large-eyed crab of the family Grapsidae, endemic to the sea coasts of New Zealand. Their carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or she ...

'' and '' Pseudohelice''.

Importance

''Neohelice granulata'' has emerged since the 1980s as a

model species A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...

in a variety of biological fields. Much of the

scientific research The scientific method is an empirical method for acquiring knowledge that has characterized the development of science since at least the 17th century (with notable practitioners in previous centuries; see the article history of scientific m ...

has focused on the species' tolerance of both fresh water and brine (euryhalinity) and its semiterrestrial habit. It has also been investigated for research into

neurophysiology Neurophysiology is a branch of physiology and neuroscience that studies nervous system function rather than nervous system architecture. This area aids in the diagnosis and monitoring of neurological diseases. Historically, it has been dominated b ...

neurobiology of learning and memory ''Neurobiology of Learning and Memory'' is a bimonthly peer-reviewed scientific journal covering neuroscience as it pertains to the processes of learning and memory. It was established in 1968 as ''Communications in Behavioral Biology Part A''. It ...

,Lessons from a crab: molecular mechanisms in different memory phases of Chasmagnathus. Romano A, Locatelli F, Freudenthal R, Merlo E, Feld M, Ariel P, Lemos D, Federman N, Fustiñana MS. Biol Bull. 2006 Jun;210(3):280-8. doi: 10.2307/4134564.

toxicology Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating expo ...

and

ecosystem dynamics An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

. Such breadth of study is unusual for a model organism. In 2009, Eduardo Spivak tallied the number of

scientific paper : ''For a broader class of literature, see Academic publishing.'' Scientific literature comprises scholarly publications that report original empirical and theoretical work in the natural and social sciences. Within an academic field, scienti ...

s published about different crab species over the previous 23 years, and found that ''Neohelice granulata'' was the sixth most studied crab species, after ''

Carcinus maenas ''Carcinus maenas'' is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab, or green shore crab. In North America and South Africa, it bears the name eur ...

'', ''

Callinectes sapidus ''Callinectes sapidus'' (from the Ancient Greek ,"beautiful" + , "swimmer", and Latin , "savory"), the blue crab, Atlantic blue crab, or regionally as the Chesapeake blue crab, is a species of crab native to the waters of the western Atlantic O ...

'', ''

Scylla serrata ''Scylla serrata'' (often called mud crab or mangrove crab, although both terms are highly ambiguous, and black crab) is an ecologically important species of crab found in the estuaries and mangroves of Africa, Australasia, and Asia. In their ...

'', ''

Cancer pagurus ''Cancer pagurus'', commonly known as the edible crab or brown crab, is a species of crab found in the North Sea, North Atlantic Ocean, and perhaps the Mediterranean Sea. It is a robust crab of a reddish-brown colour, having an oval carapace with ...

'' and ''

Metacarcinus magister The Dungeness crab (''Metacarcinus magister'') is a species of crab inhabiting eelgrass beds and water bottoms along the west coast of North America. It typically grows to across the carapace and is a popular seafood. Its common name comes from ...

'', but ahead of the invasive and edible

Chinese mitten crab The Chinese mitten crab ('; , "big sluice crab"), also known as the Shanghai hairy crab (, p ''Shànghǎi máoxiè''), is a medium-sized burrowing crab that is named for its furry claws, which resemble mittens. It is native to river ...

(''Eriocheir sinensis'') and the commercially important "snow crab", ''

Chionoecetes opilio ''Chionoecetes opilio'', a species of snow crab, also known as opilio crab or opies, is a predominantly epifaunal crustacean native to shelf depths in the northwest Atlantic Ocean and north Pacific Ocean. It is a well-known commercial species of ...

''.

Distribution and ecology

Taxonomic history

Importance

References

Further reading