Aeglidae Explained

The Aeglidae are a family of freshwater crustaceans currently restricted to South America. They are the only anomurans to be found in fresh water except for a single hermit crab species, Clibanarius fonticola, on Espiritu Santo, Vanuatu.[1] They live between 20° S and 50° S,[2] at altitudes between 320mand(-)3500mm (1,050feetand(-)11,500feetm).

Description

Aeglids resemble squat lobsters in that the abdomen is partly tucked under the thorax. The notable sexual dimorphism in the abdomen is related to the behaviour of carrying fertilised eggs on the pleopods.[3] The carapace length of the largest species may approach 6cm (02inches), but most are considerably smaller.

Aeglids are omnivorous, preferring plant matter, but also eating adult insects, molluscs, fish and fly larvae.[4]

The internal anatomy has been described for Aegla cholchol and generally resembles that of other anomurans, particularly galatheoid squat lobsters. The morphology of the antennal gland bladder differs from that in other anomurans in having a twisted tubular structure which was interpreted as an adaption to the freshwater lifestyle.[5]

Life cycle

Mating is preceded by a period of courtship, and does not coincide with moulting, as it does in many other decapods.[6] The eggs of aeglids hatch as juveniles which closely resemble the adults. They are cared for by their parents and live at the bottom of the body of water.[7]

Extant taxa

Aegla, the only extant genus in the family, contains around 74 described extant species. Of the 63 species and subspecies described by 2008, two are found in lakes, four in caves, and the remaining 57 are found mainly in rivers.[8] 42 species are found in Brazil, all restricted to the country's southern and southeastern regions (Rio Grande do Sul alone is home to 24). Other countries with species are Argentina, Bolivia, Chile, Paraguay and Uruguay.[8] More than a third of the species are considered threatened,[8] and in Brazil alone 26 species are officially recognized as threatened, including 8 critically endangered.[9]

Species

This list contains all the described species :

Fossil taxa

Haumuriaegla

Haumuriaegla glaessneri is a species known only from fossils of Haumurian age (Late Cretaceous) found near Cheviot, New Zealand.[10] At the time of its discovery, Haumuriaegla was the only known fossil from the family and the only marine member.

Protaegla

Protaegla miniscula was discovered in rocks of Albian age from the Tlayúa Formation, near Tepexi de Rodríguez, Mexico.[11]

Evolution

The family as a whole is thought to have originated around 75 million years ago in a marine environment,[8] and then entered South America from the Pacific side during the Oligocene.

Notes and References

  1. 10.2307/1548413 . Patsy A. McLaughlin . Talbot Murray . Clibanarius fonticola, new species (Anomura: Paguridea: Diogenidae), from a fresh-water pool on Espiritu Santo, Vanuatu . . 10 . 4 . 1990 . 695–702 . 1548413.
  2. . 60 . 1 . 63–70 . 2003 . Endemic and enigmatic: the reproductive biology of Aegla (Crustacea: Anomura: Aeglidae) with observations on sperm structure . Christopher C. Tudge . . 2010-03-10 . https://web.archive.org/web/20080823091257/http://museumvictoria.com.au/pages/4033/60_1_Tudge.pdf . 2008-08-23 . dead .
  3. Karine Delevati Colpo . Ludmilla Oliveira Ribeiro . Sandro Santos . 2005 . . 25 . 3 . 495–499 . Population biology of the freshwater anomuran Aegla longirostri (Aeglidae) from South Brazilian streams . 10.1651/C-2543. free .
  4. Natural diet of the freshwater anomuran Aegla longirostri (Crustacea, Anomura, Aeglidae) . Sandro Santos . Luciane Ayres-Peres . Rosana C. F. Cardoso . Carolina C. Sokolowicz . 10.1080/00222930701882466 . . 42 . 13 & 14 . 2008 . 1027–1037.
  5. Jonas Keiler . Stefan Richter . Christian S. Wirkner . 2016 . Revealing their innermost secrets: an evolutionary perspective on the disparity of the organ systems in anomuran crabs (Crustacea: Decapoda: Anomura) . . 85 . 4 . 361–386 . 2016-12-08 . https://web.archive.org/web/20170118095956/http://www.contributionstozoology.nl/vol85/nr04/a01 . 2017-01-18 . dead .
  6. Mating behavior of Aegla platensis (Crustacea, Anomura, Aeglidae) under laboratory conditions . M. Almerão . G. Bond-Buckup . M. de S. Mendonça Jr. . 2010 . . 28 . 87–94 . 10.1007/s10164-009-0159-7.
  7. Book: Littoral Communities. Macrocrustaceans . Pablo Collins . Veronica Williner . Federico Giri . 2007 . Martín H. Iriondo . Juan César Paggi . María Julieta Parma . The Middle Paraná River: Limnology of a Subtropical Wetland . limited . 978-3-540-70624-3 . . . 277–301 . 10.1007/978-3-540-70624-3_11.
  8. Global diversity of crabs (Aeglidae: Anomura: Decapoda) in freshwater . Georgina Bond-Buckup . Carlos G. Jara . Marcos Pérez-Losada . Ludwig Buckup . Keith A. Crandall . Keith A. Crandall . . 2008 . 595 . 1 . 267–273 . 10.1007/s10750-007-9022-4.
  9. [ICMBio]
  10. R. M. Feldmann . 1984 . Haumuriaegla glaessneri n. gen. and sp. (Decapoda; Anomura; Aeglidae) from Haumurian (Late Cretaceous) rocks near Cheviot, New Zealand . . 27 . 379–385 . 10.1080/00288306.1984.10422305.
  11. 10.1017/s0022336000024033. . 72 . 1 . 79–90 . Early Cretaceous arthropods from the Tlayúa Formation at Tepexi de Rodríguez, Puebla, Mexico . Rodney M. Feldmann . Francisco J. Vega . Shelton P. Applegate . Gale A. Bishop . amp.

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