Limnopilos | |
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Limnopilos naiyanetri, the type species of Limnopilos | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Malacostraca |
Order: | Decapoda |
Suborder: | Pleocyemata |
Infraorder: | Brachyura |
Family: | Hymenosomatidae |
Subfamily: | Hymenosomatinae |
Genus: | Limnopilos Chuang & Ng, 1991 |
Type species | |
Limnopilos naiyanetri |
Limnopilos is a genus of small hymenosomatid crabs endemic to Southeast Asia. The genus was described by Christina Chuang and Peter Ng in 1991, who identified the new species Limnopilos naiyanetri and distinguished it from the closely related genus Hymenicoides. Its true taxonomic classification was debated for several years, but in 2007 the discovery of a new species of crab in this genus solidified the distinction between Limnopilos and Hymenicoides. Many aspects of the genus Limnopilos are still poorly understood. Their ecology and natural history have not been studied in detail, and their reproductive cycle remains mysterious.
L. naiyanetri is the type species of this genus. The genus name Limnopilos refers to the fact that animals of this genus inhabit freshwater and are hairy. [1]
Species of this genus are quite small, the carapace reaching only 1 cm in width at maturity. The leg span may reach lengths of 2.5 cm. The carapace is circular and pilose and the dorsal surface is concave. There are distinct gastro-cardiac grooves and margin. The male chelae are stout, partially covered by dense setae, and lacking a tubercle. The rostrum is absent or weak. [2] [3] [1] The eyes, antennae, and antennules are visible from above. Both male and female abdomen-pleotelson are six-segmented. The male pleotelson is slightly trilobed. Female abdomen-pleotelson segments are distinctly demarcated. In L. sumatranus, there is a boundary between the first and second segments, or between the second and third segments in L. naiyanetri. Long, biramous pleopods are found on the second to fifth segments, developed from distal outer end of the inner surface of each segment. [4] Crabs of the genus Limnopilos can be distinguished from other hymenosomatid crabs by the following features: their telson is not distinctly trilobate, the eyes are not concealed from dorsal view by the anterior carapace, and male first pleopods have a simple structure. In both male and female individuals, all abdominal segments are free and unfused. [2] [1]
The three described species of Limnopilos are endemic to Southeast Asia. Limnopilos naiyanetri is found in Thailand. The first identified individuals were collected from a section of the Tha Chin River in the Nakhon Pathom province, where they were found on the roots of water hyacinths. The species is elusive and its presence has not been confirmed outside of this river basin. L. sumatranus was discovered in the Batang Hari River in Sumatra. L. microrhyncus is endemic to Malaysia and is found in the Kinabatangan River.
The genus Limnopilos was described in 1991 following the discovery of Limnopilos naiyanetri in Thailand. This genus and species were described by Christina Chuang and Peter Ng, but shortly thereafter in 1995 Ng reclassified the species as Hymenicoides naiyanetri. In this same publication, Ng described a new, closely related species collected from the Kinabatangan River in Malaysia: Hymenicoides microrhyncus. [3] In 1996, Ng and Chuang commented that the characteristics which made them decide the crab represented a new genus than Hymenicoides originally were the lack of a protuberance on the outer surface of the male cheliped and structural differences of the telson, but after reconsideration these seemed to be interspecific rather than intergeneric differences. [5] However, Danièle Guinot and Bertrand Richer de Forges studied specimens in 1997 and commented that the crabs may in fact represent a genus separate from Hymenicoides. [6] The genus Limnopilos and the species Limnopilos naiyanetri were confirmed in 2007, along with two new species of Limnopilos, by Tohru Naruse and Peter Ng. Specimens collected in the Batang Hari River in Sumatra were described by Naruse and Ng as L. sumatranus, and Hymenicoides microrhyncus and H. naiyanetri were reclassified to the genus Limnopilos. [2]
There are three species: [7]
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (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.
Hymenosomatidae is a family of crabs with some 110 described species in 24 genera. The following genera are placed in the Hymenosomatidae:
Tuerkayana hirtipes is a species of terrestrial crab.
Hexapus is a genus of crabs in the family Hexapodidae. It contains only three extant species found in the Indo-West Pacific. They inhabit the intertidal and subtidal areas of shorelines.
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Tiwaripotamon vietnamicum is a species of crab. Originally described as a species of Geothelphusa, it is now treated as part of the genus Tiwaripotamon, although it has also been suggested as a member of Hainanpotamon. It is only known from a single locality in Cúc Phương National Park, Ninh Bình Province, Vietnam.
Amarinus lacustris is a species of freshwater crab from Australia, New Zealand and nearby islands, where it lives in water of various salinities. It grows up to 10 mm (0.4 in) wide, with an H-shaped groove on its back. It is an omnivore and is eaten by crayfish and fish. It was first discovered in Lake Pupuke, near Auckland, and is the only freshwater crab in New Zealand.
Karstarma is a genus of karst-dwelling crabs formerly included in Sesarmoides.
Hainanpotamon is a genus of freshwater crabs, containing the following species:
Cancrocaeca xenomorpha is a species of troglobitic (cave-dwelling) freshwater crab from Sulawesi, the only species in the monotypic genus Cancrocaeca. It has been described as the world's "most highly cave-adapted species of crab".
Elamena is a genus of crab, containing the following species:
Geosesarma dennerle is a species of small land-living crabs found on Java, Indonesia.
Christmaplacidae is a family of crab in the superfamily Pseudozioidea containing the species Christmaplax mirabilis from Christmas Island, Australia, and Harryplax severus from Guam.
Latreillia elegans is a species of crab belonging to the family Latreilliidae. This family of crabs is identified by their appearance as small, long-legged crabs. The species belongs to the genus Latreillia which has only five identified species: L. elegans, L. metanesa, L. williamsi, L.valida, and L. pennifera. It was previously thought that L.elegans and L.mannengi were two separate species, but it has since been revealed that the two species are synonymous. All the thought to be differences between L.elegans and L.mannengi were in actuality overlaps. The L. mannengi is simply referring to the close relative to the species of L. elegans found in the western Atlantic.
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, for it occurs mostly in coastal areas. The genus was first described by R. Bott in 1968 as Isolapotamon (Nanhaipotamon), i.e., a subgenus of Isolapotamon.
Leptuca subcylindrica, commonly known as the Laguna Madre fiddler crab or the puffed fiddler crab, is a sparsely-studied species of fiddler crab native to southern Texas and northeastern Mexico in the Gulf of Mexico.
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Leptuca saltitanta, commonly known as the energetic fiddler crab, is a species of fiddler crab native to the eastern Pacific coasts, from El Salvador in Central America to Colombia in South America.
Leptuca terpsichores, commonly known as the dancing fiddler crab, is a species of fiddler crab native to the eastern Pacific coast of the Americas, from Nicaragua to Peru.
Limnopilos naiyanetri, commonly referred to as the Thai micro crab or pill-box crab, is a freshwater hymenosomatid crab endemic to Thailand. Its presence has only been confirmed in the Tha Chin River. The species was described in 1991 and represents the type species of Limnopilos. The Thai micro crab was first introduced to the aquarium hobby in 2008 when it was imported to Germany by the tropical fish importer Aquarium Glaser GmbH, and has slowly grown in popularity with aquarium hobbyists. It remains a relatively rare species on the market and detailed information on the husbandry of this species is scarce.