Platythelphusa

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Platythelphusa
The Tanganyika problem; an account of the researches undertaken concerning the existence of marine animals in Central Africa (1903) (14587972137).jpg
Platythelphusa armata
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Subphylum:
Crustacea
Class:
Malacostraca
Order:
Decapoda
Infraorder:
Brachyura
Family:
Potamonautidae
Genus:
Platythelphusa

Type species
Platythelphusa armataA. Milne-Edwards, 1887
Species
  • Platythelphusa armataA. Milne-Edwards, 1887
  • Platythelphusa conculcata(Cunnington, 1907)
  • Platythelphusa denticulataCapart, 1952
  • Platythelphusa echinata(Capart, 1952)
  • Platythelphusa immaculataMarijnissen, Schram, Cumberlidge & Michel, 2004
  • Platythelphusa maculata(Cunnington, 1899)
  • Platythelphusa polita(Capart, 1952)
  • Platythelphusa praelongataMarijnissen, Schram, Cumberlidge & Michel, 2004
  • Platythelphusa tuberculata(Capart, 1952)

Platythelphusa is a genus of freshwater crabs endemic to Lake Tanganyika. It has been placed in a number of families, including a monotypic family, Platythelphusidae, as well as Potamidae and its current position in the Potamonautidae, and has also been treated as a subgenus of Potamonautes . It forms a monophyletic group, possibly nested within the genus Potamonautes, which would therefore be paraphyletic. [1] The genus is the only evolutionary radiation of crabs to have occurred in a freshwater lake, and it occurred recently, probably since the Pliocene. [2] This parallels the better known radiation of cichlid fishes in Lake Tanganyika. [3] Only one other species of freshwater crab is found in Lake Tanganyika, Potamonautes platynotus . [2]

Contents

Taxonomic history

The first freshwater crab to be described from Lake Tanganyika, by Alphonse Milne-Edwards in 1887, was considered so distinct from the other crabs known up to that time that it was placed in a new genus, as Platythelphusa armata. Twelve years later, a second species was described by W. A. Cunnington, leader of the third Tanganyika Expedition, and was also placed in a separate genus, as Limnothelphusa maculata. The same author later described a third species, Platythelphusa conculata, and eventually realised that all three belonged to the same genus, reducing Limnothelphusa to a taxonomic synonym. [4]

In 1952, Capart did not recognise the species P. conculcata, but added four new species, P. denticulata, P. echinata, P. polita and P. tuberculata. Since that time, P. conculcata has been restored, and two new species have been described, P. immaculata and P. praelongata. [5]

Distribution

All nine species live in relatively shallow waters around the edge of Lake Tanganyika. While four countries border Lake Tanganyika (Burundi, Democratic Republic of the Congo, Tanzania and Zambia), only two species have been found in all four countries, P. armata and P. conculcata. One species, P. polita, has been found in all except Zambia; two (P. echinata and P. tuberculata) have been found in Burundi and Tanzania; one has been found in Tanzania and Zambia (P. maculata); one is only known from Zambia (P. praelongata) and two have only been seen in Tanzania (P. denticulata and P. immaculata). However, many of the species are poorly known, and their true distributions may be wider than is currently known. [2]

Species

Fishermen on Lake Tanganyika Burundi - Lake Tanganyika fisheries.jpg
Fishermen on Lake Tanganyika

Platythelphusa armata

As the largest species in the genus (up to 6 cm or 2.4 in in carapace width), Platythelphusa armata is subject to small-scale fishery. [5] [6] Adults live at depths of 5–30 metres (16–98 ft), while juveniles live at depths of 1–10 metres (3.3–32.8 ft), and often inhabit discarded Neothauma tanganyicense shells. The species is listed as Least Concern by the IUCN. [7]

Platythelphusa conculcata

Platythelphusa conculcata is found at depths of 20–60 metres (66–197 ft), and is listed as Least Concern by the IUCN. [8]

Platythelphusa denticulata

Platythelphusa denticulata is known from few sites, all in Tanzania. Though it may have a low population, there is no evidence of a decline and it is listed as Least Concern by the IUCN. [9]

Platythelphusa echinata

Platythelphusa echinata is found at depths of 5–30 metres (16–98 ft) on the Tanzanian and Burundian shores of Lake Tanganyika. It lives where the substrate is rocky or sandy, and occasionally uses old Neothauma shells. [10]

Platythelphusa immaculata

Platythelphusa immaculata is known from only 25 specimens, but is listed as Least Concern, because there are no apparent threats to its survival. [11]

Platythelphusa maculata

Platythelphusa maculata lives on sand and rocks, and occasionally in Neothauma shells, at depths of 1–60 metres (3.3–196.9 ft), and is listed as Least Concern. [12]

Platythelphusa polita

Platythelphusa polita lives on sand and rocks, and occasionally in Neothauma shells, at depths of 5–60 metres (16–197 ft), and is listed as Least Concern. [13]

Platythelphusa praelongata

Platythelphusa praelongata lives at the greatest depth of any Platythelphusa species, the single known specimen having been collected at 40–80 metres (130–260 ft), around Mbita Island, and is listed as Data Deficient. [14]

Platythelphusa tuberculata

Platythelphusa tuberculata has longer legs than the other species, and lives at the northern end of Lake Tanganyika, on muddy substrates. It has been found in the stomachs of fish including Chrysichthys brachynema and Bathybagrus stappersii (formerly Chrysichthys stappersii). [15]

Related Research Articles

<span class="mw-page-title-main">Lake Tanganyika</span> Rift lake in east-central Africa

Lake Tanganyika is an African Great Lake. It is the second-oldest freshwater lake in the world, the second-largest by volume, and the second-deepest, in all cases after Lake Baikal in Siberia. It is the world's longest freshwater lake. The lake is shared among four countries—Tanzania, the Democratic Republic of the Congo (DRC), Burundi, and Zambia, with Tanzania (46%) and DRC (40%) possessing the majority of the lake. It drains into the Congo River system and ultimately into the Atlantic Ocean.

<i>Potamon potamios</i> Species of crab

Potamon potamios, the Levantine freshwater crab, is a semi-terrestrial crab occurring around the eastern Mediterranean, including many Mediterranean islands, extending as far south and west as the Sinai Peninsula.

<i>Neothauma</i> Genus of gastropods

Neothauma is a genus of freshwater snail with a gill and an operculum, an aquatic gastropod mollusc in the subfamily Bellamyinae of the family Viviparidae.

<i>Ceylonthelphusa</i> Genus of crabs

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:

Ceylonthelphusa armata is a species of freshwater crabs in the family Gecarcinucidae. The species is endemic to Sri Lanka, and is classed as an endangered due to habitat degradation.

Mahatha is a genus of freshwater crabs endemic to Sri Lanka. Four of the six species are critically endangered due to habitat loss, and two are listed as Least Concern on the IUCN Red List.

<i>Oziotelphusa</i> Genus of crabs

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).

Potamonautes choloensis is a species of freshwater crustacean in the family Potamonautidae.

Potamonautes gerdalensis is a species of crustacean in the family Potamonautidae. It is found in the Democratic Republic of the Congo, Kenya, Tanzania, and Uganda. Its natural habitats are rivers and freshwater lakes. It is threatened by habitat loss.

Potamonautes infravallatus is a species of crustacean in the family Potamonautidae. It is endemic to Tanzania. Its natural habitat is rivers.

Potamonautes platycentron is a species of freshwater crab in the family Potamonautidae, which is endemic to Lake Chala in Kenya and Tanzania. It was originally described by Franz Martin Hilgendorf in 1897, as Telphusa platycentron.

Potamonautes platynotus is a species of freshwater crab which is endemic to Lake Tanganyika, where it is the only freshwater crab outside the genus Platythelphusa. Although primarily aquatic, P. platynotus is sometimes seen out of water, and can survive for many hours without water.

Potamonautes raybouldi is a species of freshwater crab. It lives in water-filled tree holes in forests in the eastern Usambara Mountains of Tanzania and the Shimba Hills in Kenya. It is threatened by deforestation resulting from the expansion of the human population, and is listed as a vulnerable species on the IUCN Red List. The species was described in 2004, and named after Professor John N. Raybould of the University of Bristol, who collected the first specimens of the species.

Potamonautes rukwanzi is a species of crustacean in the family Potamonautidae. It is endemic to Uganda. Its natural habitat is freshwater lakes.

Potamonautes unisulcatus is a species of crustacean in the family Potamonautidae. It is only found in the Uluguru Mountains, Tanzania.

<i>Deckenia</i> (crab) Genus of crabs

Deckenia is a genus of freshwater crabs from East Africa, in the family Potamonautidae, or sometimes in a family of its own, Deckeniidae. The genus was named by Hilgendorf after Karl Klaus von der Decken who collected the first examples during his expeditions to Africa. Both species live in swamps from Eyl in Somalia to Dar es Salaam, Tanzania, both in coastal areas and further inland. A third species, Deckenia alluaudi, lives in the Seychelles, and has been transferred to a separate genus, Seychellum.

<i>Potamonautes sidneyi</i> Species of crab

Potamonautes sidneyi is a species of freshwater crab in the family Potamonautidae. The common name is the Natal river crab or Sidney's river crab, although they may also be referred to as "river crabs", "fresh water crabs" or "land crabs".

<span class="mw-page-title-main">Freshwater crab</span> Common name for a non-marine crab

Around 1,300 species of freshwater crabs are distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs, which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas. As a result, a large proportion are threatened with extinction.

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".

References

  1. ↑ Neil Cumberlidge, Richard M. von Sternberg & Savel R. Daniels (2008). "A revision of the higher taxonomy of the Afrotropical freshwater crabs (Decapoda: Brachyura) with a discussion of their biogeography". Biological Journal of the Linnean Society . 93 (2): 399–413. doi: 10.1111/j.1095-8312.2007.00929.x .
  2. 1 2 3 Saskia A. E. Marijnissen; Ellinor Michel; Savel R. Daniels; Dirk Erpenbeck; Steph B. J. Menken; Frederick R. Schram (2006). "Molecular evidence for recent divergence of Lake Tanganyika endemic crabs (Decapoda: Platythelphusidae)". Molecular Phylogenetics and Evolution . 40 (2): 628–634. doi:10.1016/j.ympev.2006.03.025. PMID   16647274.
  3. ↑ Walter Salzburger; Tanja Mack; Erik Verheyen; Axel Meyer (2005). "Out of Tanganyika: Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes". BMC Evolutionary Biology . 5 (1): 17. doi: 10.1186/1471-2148-5-17 . PMC   554777 . PMID   15723698.
  4. ↑ R. von Sternberg (1999). "A cladistic analysis of Platythelphusa A. Milne-Edwards, 1887, from Lake Tanganyika, East Africa (Decapoda: Potamoidea: Platythelphusidae) with comments on the phylogenetic position of the group". Journal of Natural History . 33 (4): 493–511. doi:10.1080/002229399300218.
  5. 1 2 Saskia A. E. Marijnissen; Frederick R. Schram; Neil Cumberlidge; Ellinor Michel (2004). "Two new species of Platythelphusa A. Milne-Edwards, 1887 (Decapoda, Potamoidea, Platythelphusidae) and comments on the taxonomic position of P. denticulata Capart, 1952 from Lake Tanganyika, East Africa". Crustaceana . 77 (5): 512–532. CiteSeerX   10.1.1.516.7995 . doi:10.1163/1568540041717984.
  6. ↑ N. Cumberlidge; R. von Sternberg; I. R. Bills; H. Martin (1999). "A revision of the genus Platythelphusa A. Milne-Edwards, 1887 from Lake Tanganyika, East Africa (Decapoda: Potamoidea: Platythelphusidae)". Journal of Natural History . 33 (10): 1487–1512. CiteSeerX   10.1.1.654.5532 . doi:10.1080/002229399299860.
  7. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa armata". IUCN Red List of Threatened Species . 2008: e.T44196A10861476. doi: 10.2305/IUCN.UK.2008.RLTS.T44196A10861476.en .
  8. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa conculcata". IUCN Red List of Threatened Species . 2008: e.T44197A10861759. doi: 10.2305/IUCN.UK.2008.RLTS.T44197A10861759.en .
  9. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa denticulata". IUCN Red List of Threatened Species . 2008: e.T44552A10918760. doi: 10.2305/IUCN.UK.2008.RLTS.T44552A10918760.en .
  10. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa echinata". IUCN Red List of Threatened Species . 2008: e.T44198A10862040. doi: 10.2305/IUCN.UK.2008.RLTS.T44198A10862040.en .
  11. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa immaculata". IUCN Red List of Threatened Species . 2008: e.T44553A10918991. doi: 10.2305/IUCN.UK.2008.RLTS.T44553A10918991.en .
  12. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa maculata". IUCN Red List of Threatened Species . 2008: e.T44518A10910802. doi: 10.2305/IUCN.UK.2008.RLTS.T44518A10910802.en .
  13. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa polita". IUCN Red List of Threatened Species . 2008: e.T44519A10911213. doi: 10.2305/IUCN.UK.2008.RLTS.T44519A10911213.en .
  14. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa praelongata". IUCN Red List of Threatened Species . 2008: e.T44554A10919219. doi: 10.2305/IUCN.UK.2008.RLTS.T44554A10919219.en .
  15. ↑ N. Cumberlidge & S. A. E. Marijnissen (2008). "Platythelphusa tuberculata". IUCN Red List of Threatened Species . 2008: e.T44199A10862353. doi: 10.2305/IUCN.UK.2008.RLTS.T44199A10862353.en .
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