''Nanhaipotamon hongkongense'' is a species of

freshwater crab Around 1,300 species of freshwater crabs are distributed throughout the tropics and subtropics, divided among eight family (biology), families. They show direct development and maternal care of a small number of offspring, in contrast to marine c ...

of the genus ''

Nanhaipotamon ''Nanhaipotamon'' is a genus of freshwater crabs, in the subfamily Potamiscinae, found in southern China and Taiwan. As of 2018, 18 species have been described. The genus is named after the South China Sea (; literally: 'South Sea'), for it occur ...

'', known to occur in

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

(

Hong Kong Island Hong Kong Island () is an island in the southern part of Hong Kong. The island, known originally and on road signs simply as "Hong Kong", had a population of 1,289,500 and a population density of , . It is the second largest island in Hong Kon ...

New Territories The New Territories (N.T., Traditional Chinese characters, Chinese: ) is one of the three areas of Hong Kong, alongside Hong Kong Island and Kowloon. It makes up 86.2% of Hong Kong's territory, and contains around half of the population of H ...

Lantau Island Lantau Island (also Lantao Island, Lan Tao or Lan Tau) is the largest island in Hong Kong, located west of Hong Kong Island and the Kowloon Peninsula, and is part of the New Territories. Administratively, most of Lantau Island is part of the ...

and a few smaller islands) and adjacent areas in

Shenzhen Shenzhen is a prefecture-level city in the province of Guangdong, China. A Special economic zones of China, special economic zone, it is located on the east bank of the Pearl River (China), Pearl River estuary on the central coast of Guangdong ...

and

Dongguan Dongguan,; pinyin: alternately romanized via Cantonese as Tungkun, is a prefecture-level city in central Guangdong Province, China. An important industrial city in the Pearl River Delta, Dongguan borders the provincial capital of Guangzhou t ...

Mainland China "Mainland China", also referred to as "the Chinese mainland", is a Geopolitics, geopolitical term defined as the territory under direct administration of the People's Republic of China (PRC) in the aftermath of the Chinese Civil War. In addit ...

Description and life history

''Nanhaipotamon hongkongense'' is a burrowing species that digs burrows into muddy banks of small rivers and creeks or moist soil. It is a nocturnal species that mostly stays in its burrow during the day and comes out at night or after heavy rainfalls. Offspring hatch as miniature versions of adult crabs after direct development, like with all potamid crabs.

Distribution and habitat

This species is semiterrestrial and inhabits the banks of hillstreams, but can also be found in places far away from running water, such as moist areas were groundwater seeps through the soil, generally in secondary evergreen broadleaf forests. Whereas adults are rarely reported from actual aquatic habitats, juveniles and small adults may be found under stones or leaves in small ditches, creeks and ponds. ''N. hongkongense'' occurs from 17 to 514 meters above sea level. Although it has been known to tolerate certain amounts of pollution, such as plastic trash, it is not abundant in modified landscapes and in or close to densely populated human settlements, there is, however, anecdotal evidence of single crabs in schools and residential areas. First considered to be a

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

, it was recorded from cities bordering

, namely

and

Conservation

As of 2008, ''N. hongkongense'' is assessed to be "

Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

" by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

, Major threats to the species include

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and pollution. Researchers reckon that there may exist several isolated sub-populations due to

habitat fragmentation Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological proces ...

, since many natural water courses have been piped or channelized in their downstream sections. The close proximity of habitats with large cities and the expected growth of them may put pressure on existing populations in the future. Currently, ''N. hongkongense'' is present in several protected areas in

References

{{Taxonbar, from=Q13874153 Potamoidea Freshwater crustaceans of Asia Crustaceans described in 1940 Invertebrates of Hong Kong

Description and life history

Distribution and habitat

Conservation

See also

References