Aeglidae

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

Aeglidae, commonly known as pancoras are a family of freshwater crustaceans of South America. They are the only fresh water anomurans except for the hermit crab Clibanarius fonticola of Vanuatu. They live between 20° S and 50° S, at altitudes between 320 and 3,500 m (1,050–11,480 ft).

Description

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

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.

Classification

Aeglidae is thought to have originated around 75 million years ago and originally inhabited marine environments. The animals began colonizing South America during the Oligocene. They started from the Pacific Coast, and as time went on, slowly spread across the entire continent.

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. 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. More than a third of the species are considered threatened, and in Brazil alone 26 species are officially recognized as threatened, including 8 critically endangered.

Phylogeny

The placement of Aeglidae within Anomura can be shown in the 2026 cladogram found below.

Brachyura ("true" crabs)

Anomura
Galatheoidea

Porcellanidae (porcelain crabs)

Munidopsidae (squat lobsters)

Galatheidae (squat lobsters)

Munididae (squat lobsters)

Pylochelidae (symmetrical hermit crabs)

Lomisidae (hairy stone crabs)

Hippoidea

Blepharipodidae (mole crabs)

Albuneidae (mole crabs)

Hippidae (mole crabs)

Paguroidea

Diogenidae (left-handed hermit crabs)

Coenobitidae (terrestrial hermit crabs)

List of species

This list contains all the described species as of 2013:

Fossil taxa

Haumuriaegla

Haumuriaegla glaessneri is a species known only from fossils of Haumurian age (Late Cretaceous) found near Cheviot, New Zealand. 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.

Behavior and life history

Diet

Pancoras are omnivorous, preferring plant matter, but also eating adult insects, molluscs, fish and fly larvae.

Mating and reproduction

Mating is preceded by a period of courtship, and does not coincide with moulting, as it does in many other decapods. The eggs of pancoras 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.

Relationship with humans

In fly fishing

As pets

Conservation status

References

  1. ↑ Redacción (2017-03-10). "Pancora | Características, hábitat, reproducción, alimentación | Animal". Animales (in Spanish). Retrieved 2026-07-16.
  2. ↑ 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. Bibcode:1990JCBio..10..695M. doi:10.2307/1548413. JSTOR 1548413.
  3. ↑ 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. doi:10.24199/j.mmv.2003.60.9. Archived from the original (PDF) on 2008-08-23. Retrieved 2010-03-10.
  4. 1 2 3 4 5 6 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. Bibcode:2008HyBio.595..267B. doi:10.1007/s10750-007-9022-4.
  5. ↑ 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. Bibcode:2005JCBio..25..495S. doi:10.1651/C-2543.
  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. doi:10.1163/18759866-08504001. Archived from the original on 2017-01-18. Retrieved 2016-12-08.
  7. 1 2 3 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): 211–223. Bibcode:2013Naup...21..211S. doi:10.1590/S0104-64972013000200008.
  8. ↑ 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.
  9. ↑ Hwang, Hee-seung; Jung, Jibom (2026-01-12). "Comparative phylomitogenomic analyses provide insights into adaptation and carcinization in Anomura". Animal Cells and Systems. 30 (1): 83–103. doi:10.1080/19768354.2025.2607863. ISSN 1976-8354.
  10. ↑ 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.
  11. ↑ 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. Bibcode:2012JCBio..32..529B. doi:10.1163/193724012X635935.
  12. ↑ 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 (inactive 1 July 2025).{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link)
  13. ↑ Rodney M. Feldmann; Francisco J. Vega; Shelton P. Applegate & Gale A. Bishop (1998). "Early Cretaceous arthropods from the Tlayúa Formation at Tepexi de Rodríguez, Puebla, Mexico". Journal of Paleontology. 72 (1): 79–90. Bibcode:1998JPal...72...79F. doi:10.1017/s0022336000024033.
  14. ↑ 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. Bibcode:2008JNatH..42.1027S. doi:10.1080/00222930701882466.
  15. ↑ 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: 87–94. doi:10.1007/s10164-009-0159-7.
  16. ↑ 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.
  1. ↑ List comprises species listed by McLaughlin et al. (2010), with updates from Santos et al. (2012) and Santos et al. (2013).