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 320 and 3,500 m (1,050–11,480 ft).[3]

Aeglidae
Temporal range: Albian–Recent
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
(unranked): Reptantia
Infraorder: Anomura
Superfamily: Aegloidea
Dana, 1852
Family: Aeglidae
Dana, 1852
Genera
  • Aegla Leach, 1820
  • Haumuriaegla Feldmann, 1984
  • Protaegla Feldmann et al., 1998

Description

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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.[4] The carapace length of the largest species may approach 6 cm (2.4 in), but most are considerably smaller.[3]

Aeglids are omnivorous, preferring plant matter, but also eating adult insects, molluscs, fish and fly larvae.[5]

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.[6]

Life cycle

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Mating is preceded by a period of courtship, and does not coincide with moulting, as it does in many other decapods.[7] 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.[8]

Extant taxa

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Aegla, the only extant genus in the family, contains around 74 described extant species.[9] 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.[3] 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).[9] Other countries with species are Argentina, Bolivia, Chile, Paraguay and Uruguay.[3] More than a third of the species are considered threatened,[3] and in Brazil alone 26 species are officially recognized as threatened, including 8 critically endangered.[10]

Species

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This list contains all the described species as of 2013:[Note 1]

Fossil taxa

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Haumuriaegla

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Haumuriaegla glaessneri is a species known only from fossils of Haumurian age (Late Cretaceous) found near Cheviot, New Zealand.[13] At the time of its discovery, Haumuriaegla was the only known fossil from the family and the only marine member.

Protaegla

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Protaegla miniscula was discovered in rocks of Albian age from the Tlayúa Formation, near Tepexi de Rodríguez, Mexico.[14]

Evolution

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The family as a whole is thought to have originated around 75 million years ago in a marine environment,[3] and then entered South America from the Pacific side during the Oligocene.

References

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  1. ^ Patsy A. McLaughlin; Talbot Murray (1990). "Clibanarius fonticola, new species (Anomura: Paguridea: Diogenidae), from a fresh-water pool on Espiritu Santo, Vanuatu". Journal of Crustacean Biology. 10 (4): 695–702. doi:10.2307/1548413. JSTOR 1548413.
  2. ^ Christopher C. Tudge (2003). "Endemic and enigmatic: the reproductive biology of Aegla (Crustacea: Anomura: Aeglidae) with observations on sperm structure" (PDF). Memoirs of Museum Victoria. 60 (1): 63–70. Archived from the original (PDF) on 2008-08-23. Retrieved 2010-03-10.
  3. ^ a b c d e f Georgina Bond-Buckup; Carlos G. Jara; Marcos Pérez-Losada; Ludwig Buckup; Keith A. Crandall (2008). "Global diversity of crabs (Aeglidae: Anomura: Decapoda) in freshwater". Hydrobiologia. 595 (1): 267–273. doi:10.1007/s10750-007-9022-4.
  4. ^ Karine Delevati Colpo; Ludmilla Oliveira Ribeiro; Sandro Santos (2005). "Population biology of the freshwater anomuran Aegla longirostri (Aeglidae) from South Brazilian streams". Journal of Crustacean Biology. 25 (3): 495–499. doi:10.1651/C-2543.
  5. ^ Sandro Santos; Luciane Ayres-Peres; Rosana C. F. Cardoso; Carolina C. Sokolowicz (2008). "Natural diet of the freshwater anomuran Aegla longirostri (Crustacea, Anomura, Aeglidae)". Journal of Natural History. 42 (13 & 14): 1027–1037. doi:10.1080/00222930701882466.
  6. ^ 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)". Contributions to Zoology. 85 (4): 361–386. Archived from the original on 2017-01-18. Retrieved 2016-12-08.
  7. ^ M. Almerão; G. Bond-Buckup; M. de S. Mendonça Jr. (2010). "Mating behavior of Aegla platensis (Crustacea, Anomura, Aeglidae) under laboratory conditions". Journal of Ethology. 28: 87–94. doi:10.1007/s10164-009-0159-7.
  8. ^ Pablo Collins; Veronica Williner; Federico Giri (2007). "Littoral Communities. Macrocrustaceans". In Martín H. Iriondo; Juan César Paggi; María Julieta Parma (eds.). The Middle Paraná River: Limnology of a Subtropical Wetland. Heidelberg: Springer. pp. 277–301. doi:10.1007/978-3-540-70624-3_11. ISBN 978-3-540-70624-3.
  9. ^ a b c Sandro Santos; Carlos G. Jara; Marlise Ladvocat Bartholomei-Santos; Marcos Pérez-Losada; Keith A. Crandall (2013). "New species and records of the genus Aegla Leach, 1820 (Crustacea, Anomura, Aeglidae) from the West-Central region of Rio Grande do Sul, Brazil". Nauplius. 21 (2). doi:10.1590/S0104-64972013000200008.
  10. ^ ICMBio (Ministry of the Environment, Brazil): Portaria MMA nº 445, de 17 de dezembro de 2014 Archived 2022-05-03 at the Wayback Machine. Lista de Especies Ameaçadas - Saiba Mais. Retrieved 1 December 2018.
  11. ^ Patsy A. McLaughlin; Rafael Lemaitre; Keith A. Crandall (2010). "Annotated checklist of anomuran decapod crustaceans of the world (exclusive of the Kiwaoidea and families Chirostylidae and Galatheidae of the Galatheoidea). Part III – Aegloidea" (PDF). Zootaxa. Suppl. 23: 131–137. Archived from the original (PDF) on 2012-03-02. Retrieved 2010-11-04.
  12. ^ Sandro Santos; Georgina Bond-Buckup; Ludwig Buckup; Marcos Pérez-Losada; Maegan Finley; Keith A. Crandall (2012). "Three new species of Aegla (Anomura) freshwater crabs from the upper Uruguay River hydrographic basin in Brazil". Journal of Crustacean Biology. 32 (4): 529–540. doi:10.1163/193724012X635935.
  13. ^ R. M. Feldmann (1984). "Haumuriaegla glaessneri n. gen. and sp. (Decapoda; Anomura; Aeglidae) from Haumurian (Late Cretaceous) rocks near Cheviot, New Zealand". New Zealand Journal of Geology and Geophysics. 27: 379–385. doi:10.1080/00288306.1984.10422305.
  14. ^ Rodney M. Feldmann; Francisco J. Vega; Shelton P. Applegate & Gale A. Bishop. "Early Cretaceous arthropods from the Tlayúa Formation at Tepexi de Rodríguez, Puebla, Mexico". Journal of Paleontology. 72 (1): 79–90. doi:10.1017/s0022336000024033.
  1. ^ List comprises species listed by McLaughlin et al. (2010),[11] with updates from Santos et al. (2012)[12] and Santos et al. (2013).[9]
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