| Gecarcinucidae | |
|---|---|
 | |
| Thelphusa indica | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Section: | Eubrachyura |
| Subsection: | Heterotremata |
| Superfamily: | Gecarcinucoidea |
| Family: | Gecarcinucidae Rathbun, 1904 [1] |
| Genera | |
The Gecarcinucidae are a family of true freshwater crabs. They are found throughout South Asia, Southeast Asia and New Guinea, with a single genus found in Australia. [2]
The family Parathelphusidae is now demoted to the rank of subfamily, as the Parathelphusinae, within the Gecarcinucidae. [3] "Family" Parathelphusidae is now considered as a junior synonym. [4]
The Gecarcinucidae are thought to have originated in the Indian subcontinent when it was an island continent in the Paleogene, despite not being of ancient Gondwanan origins themselves (unlike other lineages that are thought to have originated in Insular India). Divergence estimates indicate that the Gecarcinucidae originate from Southeast Asian ancestors that dispersed to India during the middle Eocene, before India collided with Asia. This is thought to have occurred due to India drifting close enough to Southeast Asia to allow for biotic exchange between both regions. As the Gecarcinucidae are a freshwater group that could not disperse via marine habitats, this indicates that temporary land bridges may have formed in the Eocene between India and Southeast Asia, allowing for the dispersal of freshwater organisms to India while it was still isolated. Following the India-Asia collision, the Gecarcinucidae dispersed back into mainland Asia, and from there to Australasia. [5]
The Gecarcinucidae are thought to be the sister group to the Potamoidea (the superfamily comprising the Potamidae and Potamonautidae). [5]
Ceylonthelphusa is a genus of freshwater crabs endemic to Sri Lanka, where they live in moist lowland forests, swamps and rivers. Many of the species are on the IUCN Red List of threatened species, with the greatest risk factor being habitat loss. Ceylonthelphusa contains these species:
Parathelphusinae is a subfamily of freshwater crabs, which was formerly placed in the family Parathelphusidae; they are mainly found in South and Southeast Asia, but also found elsewhere in Asia and in Australia. The family is now considered as a junior synonym of the family Gecarcinucidae.
Oziotelphusa is a genus of freshwater crabs in the family Gecarcinucidae. Its members are found in Sri Lanka and southern India. The genus was formerly placed within family Parathelphusidae, but now it is accepted that Parathelphusidae is the junior synonym of Gecarcinucidae.
Perbrinckia is a genus of freshwater crabs of the family Gecarcinucidae that is endemic to Sri Lanka, named after Per Brinck. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical swamps, and rivers. It contains 14 species, most of which are included on the IUCN Red List as critically endangered species (CR) or vulnerable species (VU) because they are threatened by habitat loss; only one species is of least concern (LC).
Spiralothelphusa fernandoi is a species of crab in the family Gecarcinucidae.
Pseudothelphusidae is a family of freshwater crabs found chiefly in mountain streams in the Neotropics. They are believed to have originated in the Greater Antilles and then crossed to Central America via a Pliocene land bridge. Some species of this family are troglobitic.
Potamidae is a family of freshwater crabs. It includes more than 650 species and nearly 100 genera, which are placed into two subfamilies: Potaminae and Potamiscinae.
Somanniathelphusa is a genus of freshwater crabs found in southeast China, Taiwan, and southeast Asia. It includes the following species:
Geosesarma is genus of small freshwater or terrestrial crabs, typically less than 10 mm (0.4 in) across the carapace. They live and reproduce on land with the larval stages inside the egg. They are found from India, through Southeast Asia, to the Solomon Islands and Hawaii.
Potamon is a genus of freshwater or semiterrestrial crabs mainly found from Southern Europe through the Middle East, and as far east as north-western India. The only exception is the North African P. algeriense, which also is the only potamid of mainland Africa. Twenty species are currently recognised. These crabs are omnivores that have a broad ecological tolerance. The adult Potaman reach up to 50 mm in size during their 10-12 year life span.
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.
Johora is a genus of freshwater crabs found in the Malay Peninsula and surrounding islands. It includes the following species:
Seychellum alluaudi is a species of freshwater crab endemic to the Seychelles, and the only true freshwater crab in that country. It lives in rainforest streams on the archipelago's granitic high islands. Although it may be abundant, little is known about its biology. If its habitat were to decline in quality, S. alluaudi might become endangered, but it is currently listed as Vulnerable on the IUCN Red List.
Migmathelphusa olivacea is a species of freshwater crab found in Lake Poso on the Indonesian island of Sulawesi. It is the only species in its genus. It is listed by the IUCN as Endangered, given "its extent of occurrence and area of occupancy is less than 500 square kilometres (190 sq mi)", and its individuals being found in less than five locations. There is also a "decline in the extent and quality of its habitat and it is not found in a protected area". Being found around a lake, "present and future threats to this species include human-induced habitat loss/degradation due to population increases and industrial and agrarian development".
Indochinamon is a genus of freshwater crabs, typically found in the Indo-China region.
Eosamon is a genus of freshwater crabs in the subfamily Potamiscinae, found in East and South-East Asia.
Mekhongthelphusa is a genus of freshwater crabs in the family Gecarcinucidae, found in South-East Asia.
Insular India was an isolated landmass which became the Indian subcontinent. Across the latter stages of the Cretaceous and most of the Paleocene, following the breakup of Gondwana, the Indian subcontinent remained an isolated landmass as the Indian Plate drifted across the Tethys Ocean, forming the Indian Ocean. The process of India's separation from Madagascar first began 88 million years ago, but complete isolation only occurred towards the end of the Maastrichtian, a process that has been suggested to be the creation of the Deccan Traps. Soon after, the land mass moved northward rather quickly, until contact with Asia was established 55 million years ago. Even then, both landmasses did not become fully united until around 35 million years ago, and periods of isolation occurred as recently as 24 million years ago.
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.
Gubernatoriana is a genus of freshwater crabs, found among the Western Ghats in India.