Coelacanth

Coelacanths
Temporal range: Early Devonian – Recent,[1]
Live coelacanth (Latimeriidae) off Pumula on the KwaZulu-Natal South Coast, South Africa
Specimen of Axelrodichthys araripensis (Mawsoniidae) from the Early Cretaceous of Brazil
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Osteichthyes
Clade: Sarcopterygii
Class:
Cope, 1871
Type species
†Coelacanthus granulatus
Agassiz, 1839
Families
  • †Miguashaiidae
  • †Diplocercidae
  • †Hadronectoridae
  • †Sasseniidae
  • †Rhabdodermatidae
  • Coelacanthiformes
    • †Coelacanthidae
    • †Rebellatricidae
    • †Laugiidae
    • †Whiteiidae
    • †Axeliidae
    • Latimerioidei
      • Latimeriidae
      • †Mawsoniidae

And see text

Coelacanths (/ˈsiːləkænθ/ ⓘ SEE-lə-kanth) are an ancient group of lobe-finned fish (Sarcopterygii) in the class Actinistia.[2][3] As sarcopterygians, they are more closely related to lungfish and tetrapods (the terrestrial vertebrates including living amphibians, reptiles, birds and mammals) than to ray-finned fish.

The name coelacanth originates from the Permian genus Coelacanthus, which was the first scientifically named genus of coelacanths (in 1839), becoming the type genus of Coelacanthiformes as other species were discovered and named.[4][5] Well-represented in freshwater and marine deposits from as early as the Devonian period (more than 410 million years ago), they were thought to have become extinct in the Late Cretaceous, around 66 million years ago.

The first living species, Latimeria chalumnae, the West Indian Ocean coelacanth, was described from specimens fished off the coast of South Africa from 1938 onward;[6][7] they are now also known to inhabit the seas around the Comoro Islands off the east coast of Africa. The second species, Latimeria menadoensis, the Indonesian coelacanth, was discovered in the late 1990s, which inhabits the seas of Eastern Indonesia, from Manado to Papua.[8]

The coelacanth (more accurately, the extant genus Latimeria) is often considered an example of a "living fossil" in popular science because it was considered the sole remaining member of a taxon otherwise known only from fossils (a biological relict),[9][10]: 1  evolving a bodyplan similar to its current form approximately 400 million years ago.[1] However, studies of fossil coelacanths have shown that coelacanth body shapes (and their niches) were much more diverse than what was previously thought, and often differed significantly from Latimeria.[11][12][13]

  1. ^ a b Johanson, Z.; Long, J. A; Talent, J. A; Janvier, P.; Warren, J. W (2006). "Oldest coelacanth, from the Early Devonian of Australia". Biology Letters. 2 (3): 443–6. doi:10.1098/rsbl.2006.0470. PMC 1686207. PMID 17148426.
  2. ^ Nelson, Joseph S. (16 March 2016). Fishes of the World. John Wiley & Sons. pp. 103–105. ISBN 978-1-119-22081-7. OCLC 951128215.
  3. ^ "Order Summary for Coelacanthiformes". fishbase.se. Retrieved 13 March 2023.
  4. ^ Agassiz, L. (1839). Recherches sur les poissons fossiles II. Neuchâtel: Petitpierre. pp. xxxvi–xxxviii. doi:10.5962/bhl.title.4275. Retrieved 12 May 2025.
  5. ^ Osterloff, Emily. "Coelacanths: the fish that 'outdid' the Loch Ness Monster". Natural History Museum, London. Retrieved 12 May 2025.
  6. ^ Smith, J. L. B. (1956). Old Fourlegs: the Story of the Coelacanth. Longmans Green. p. 24.
  7. ^ Lavett Smith, C.; Rand, Charles S.; Schaeffer, Bobb; Atz, James W. (1975). "Latimeria, the Living Coelacanth, is Ovoviviparous". Science. 190 (4219): 1105–6. Bibcode:1975Sci...190.1105L. doi:10.1126/science.190.4219.1105. S2CID 83943031.
  8. ^ Yokoyama, Shozo; Zhang, Huan; Radlwimmer, F. Bernhard; Blow, Nathan S. (1999). "Adaptive evolution of color vision of the Comoran coelacanth (Latimeria chalumnae)". Proceedings of the National Academy of Sciences. 96 (11): 6279–84. Bibcode:1999PNAS...96.6279Y. doi:10.1073/pnas.96.11.6279. PMC 26872. PMID 10339578.
  9. ^ Latham, Katherine (8 May 2024). "The deep ocean photographer that captured a 'living fossil'". bbc.com. British Broadcasting Corporation. Retrieved 13 June 2025.
  10. ^ Forey, Peter L (1998). History of the Coelacanth Fishes. London: Chapman & Hall. pp. 1, 3, 6, 13–16, 19, 27, 32, 35–40. ISBN 978-0-412-78480-4.
  11. ^ Friedman, Matt; Coates, Michael I.; Anderson, Philip (2007). "First discovery of a primitive coelacanth fin fills a major gap in the evolution of lobed fins and limbs". Evolution & Development. 9 (4): 329–37. doi:10.1111/j.1525-142X.2007.00169.x. PMID 17651357. S2CID 23069133.
  12. ^ Friedman, Matt; Coates, Michael I. (2006). "A newly recognized fossil coelacanth highlights the early morphological diversification of the clade". Proceedings of the Royal Society B: Biological Sciences. 273 (1583): 245–50. doi:10.1098/rspb.2005.3316. JSTOR 25223279. PMC 1560029. PMID 16555794.
  13. ^ Wendruff, Andrew J.; Wilson, Mark V. H. (2012). "A fork-tailed coelacanth, Rebellatrix divaricerca, gen. Et sp. Nov. (Actinistia, Rebellatricidae, fam. Nov.), from the Lower Triassic of Western Canada". Journal of Vertebrate Paleontology. 32 (3): 499–511. Bibcode:2012JVPal..32..499W. doi:10.1080/02724634.2012.657317. S2CID 85826893.
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