Acanthuridae

Surgeonfish
Temporal range: Eocene–recent
Sohal surgeonfish, Acanthurus sohal. The orange mark on the tail peduncle shows where the spine is folded in.
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Division: Teleostei
Order: Acanthuriformes
Suborder: Acanthuroidei
Family: Acanthuridae
Bonaparte, 1835
Type species
Acanthurus triostegus
Genera

see text

The exposed caudal spine of Acanthurus xanthopterus

The Acanthuridae are a family of ray-finned fishes, which includes surgeonfishes, tangs, and unicornfishes. The family includes about 86 extant species of marine fishes living in tropical seas, usually around coral reefs. Many of the species are brightly colored and popular in aquaria.

Etymology

The family name comes from Ancient Greek terms ἄκανθα (ákantha), meaning "spine", and οὐρά (ourá), meaning "tail", a reference to the scalpel-like bony plates on the type species's caudal peduncle. In the early 1900s, the family was called Hepatidae.

Subfamilies and genera

Watercolor of an Acanthurus.
An 1865 watercolor of an Acanthurus by Jacques Burkhardt

The Acanthuridae family contains these extant subfamilies and genera:

Evolution and fossil record

Several extinct genera are known from fossils dating from the Eocene to Miocene:

Eocene genera

A particularly large diversity of fossil surgeonfish is known from the Monte Bolca Lagerstätte of Italy. These represent some of the earliest representatives of the individual tribes within the Acanthuridae.

Oligocene genera

Miocene genera

Morphology

Teeth of the striated surgeonfish

The distinctive characteristic of the family is that they have scalpel-like modified scales, one or more on either side of the peduncle of the tail. The spines are dangerously sharp and may seriously injure anyone who carelessly handles such a fish. The dorsal, anal, and caudal fins are large, extending for most of the length of the body. Their mouths are small and have a single row of teeth adapted to grazing on algae.

Surgeonfishes sometimes feed as solitary individuals, but they often travel and feed in schools, which may be a mechanism for overwhelming the highly aggressive defense responses of small, territorial damselfishes that vigorously guard small patches of algae on coral reefs. Most species are fairly small, with a maximum length of 15–40 cm (6–15.5 in), but some in the genus Acanthurus, some in the genus Prionurus, and most species in the genus Naso may grow larger; the whitemargin unicornfish (Naso annulatus) is the largest species in the family, reaching a length up to 1 m (3 ft 3 in). These fishes may grow quickly in aquaria, so average growth size and suitability should be checked before adding them to any marine aquarium.

Acronurus stage of an unidentified Acanthurus near Morotai

A larval acanthurid, known as an acronurus, looks strikingly different from the juvenile and adult forms of the same individual. It is mostly transparent and tends to have a pelagic lifestyle, living in open water for an extended time before settling on the ocean bottom near the shore, where it develops into the juvenile and ultimately the adult form.

Symbiotic bacteria

Acanthurids are the only known hosts of the bacteria of the genus Epulopiscium. These bacteria affect the digestion of surgeonfish, enabling them to digest the algae in their diet.

References

  1. 1 2 Richard van der Laan; William N. Eschmeyer & Ronald Fricke (2014). "Family-group names of recent fishes". Zootaxa. 3882 (2): 1–230. doi:10.11646/zootaxa.3882.1.1. PMID 25543675.
  2. 1 2 Froese, Rainer; Pauly, Daniel (eds.). "Family Acanthuridae". FishBase. February 2007 version.
  3. ↑ Seale, Alvin (1909). "New Species of Philippine Fishes". Philippine Journal of Science. 4 (6). Bureau of Science in Manila. doi:10.5962/bhl.title.54135.
  4. ↑ J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. pp. 497–502. ISBN 978-1-118-34233-6. Archived from the original on 2019-04-08. Retrieved 2023-07-10.
  5. ↑ Samuel Hubbard Scudder (1884). "Nomenclator Zoologicus: An Alphabetical List of All Generic Names that Have Been Employed by Naturalists for Recent and Fossil Animals from the Earliest Times to the Close of the Year 1879". Bulletin of the United States National Museum (19).
  6. ↑ Carnevale, G.; Bannikov, Alexandre F.; Marramà, G.; Tyler, James C.; Zorzin., R. (2014). "The Bolca Fossil-Lagerstätte: A window into the Eocene World. 5. The Pesciara- Monte Postale Fossil-Lagerstätte: 2. Fishes and other vertebrates. Excursion guide" (PDF). Rendiconti della Società Paleontologica Italiana. 4 (1): i–xxvii. hdl:10088/25678.
  7. ↑ Carnevale, Giorgio; Tyler, James C. (2018-04-23). "The caudal skeleton of Arambourgthurus scombrurus (Arambourg, 1967), a Paleogene oceanic surgeonfish". Proceedings of the Biological Society of Washington. 131 (1): 101–110. doi:10.2988/17-00023. ISSN 0006-324X.
  8. 1 2 Tyler, James C.; Micklich, Norbert R. (2011-10-01). "A new genus and species of surgeon fish (Perciformes, Acanthuridae) from the Oligocene of Kanton Glarus, Switzerland". Swiss Journal of Palaeontology. 130 (2): 203–216. doi:10.1007/s13358-011-0016-5. ISSN 1664-2384.
  9. ↑ Klanten, Selma O.; Herwerden, Lynne van; Choat, J. Howard; Blair, David (2004-07-01). "Patterns of lineage diversification in the genus Naso (Acanthuridae)". Molecular Phylogenetics and Evolution. 32 (1): 221–235. doi:10.1016/j.ympev.2003.11.008. ISSN 1055-7903.
  10. ↑ Tyler, James C. (1997-01-01). "The Miocene fish Marosichthys, a putative tetraodontiform, actually a perciform surgeon fish (Acanthuridae) related to the recent Naso". Beaufortia. 47 (1): 1–10. ISSN 0067-4745.
  11. ↑ Sorenson, L., Santini, F., Carnevale, G. and Alfaro, M.E. (2013) "A multi-locus timetree of surgeonfishes (Acanthuridae, Percomorpha), with revised family taxonomy". Molecular phylogenetics and evolution, 68(1): 150–160. doi:10.1016/j.ympev.2013.03.014
  12. ↑ W. S. Alevizon (1976). "Mixed schooling and its possible significance in a tropical western Atlantic parrotfish and surgeonfish". Copeia. 1976 (4): 797–798. doi:10.2307/1443464. JSTOR 1443464.
  13. ↑ Jonna, R. Jamil. "Acanthuridae (Surgeonfishes, tangs, unicornfishes)". Animal Diversity Web. Retrieved 2024-04-20.
  14. ↑ Miyake, Sou; Ngugi, David Kamanda; Stingl, Ulrich (2015). "Diet strongly influences the gut microbiota of surgeonfishes". Molecular Ecology. 24 (3): 656–672. doi:10.1111/mec.13050. ISSN 1365-294X. PMID 25533191. S2CID 206181801.
  15. ↑ Fishelson, L. (1999-03-01). "Polymorphism in gigantobacterial symbionts in the guts of surgeonfish (Acanthuridae: Teleostei)". Marine Biology. 133 (2): 345–351. doi:10.1007/s002270050473. ISSN 1432-1793. S2CID 84816281.
  16. ↑ Pollak, Peggy E.; Montgomery, W. Linn (1994-08-01). "Giant bacterium (Epulopiscium fishelsoni ) influences digestive enzyme activity of an herbivorous surgeonfish (Acanthurus nigrofuscus)". Comparative Biochemistry and Physiology Part A: Physiology. 108 (4): 657–662. doi:10.1016/0300-9629(94)90352-2. ISSN 0300-9629.