Eelpout
Gymnelus hemifasciatus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Scorpaeniformes
Suborder: Zoarcoidei
Family: Zoarcidae
Swainson, 1839[1][2]
Subfamilies

see text

The eelpouts are the ray-finned fish family Zoarcidae. As the common name suggests, they are somewhat eel-like in appearance. All of the roughly 300 species are marine and mostly bottom-dwelling, some at great depths. Eelpouts are predominantly found in the Northern Hemisphere. The arctic, north pacific and north Atlantic oceans have the highest concentration of species, however species are found around the globe.

They are conventionally placed in the "perciform" assemblage; in fact, the Zoarcoidei seem to be specialized members of the Gasterosteiformes-Scorpaeniformes group of Acanthopterygii.[3]

The largest member of the family is Zoarces americanus, which may reach 1.1 m in length. Other notable genera include Lycodapus and Gymnelus.

Taxonomy

The eelpout family was first proposed as the family Zoarchidae in 1839 by the English naturalist William John Swainson but the spelling was changed to Zoarcidae after the spelling of the genus Zoarces was corrected by Theodore Gill in 1861.[1] The 5th edition of Fishes of the World classifies this family within the suborder Zoarcoidei, within the order Scorpaeniformes.[4] Other authorities classify this family in the infraorder Zoarcales wihin the suborder Cottoidei of the Perciformes because removing the Scorpaeniformes from the Perciformes renders that taxon non monophyletic.[5]

Fishes of the World mentions four subfamilies but does not assign genera to the subfamilies[4] but these were set out in Anderson and Federov's Annotated Checklist[6] and this has been followed by FishBase[7] and Catalog of Fishes.[8]

Subfamilies and genera

The eelpouts are classified into four subfamilies and 61 genera with around 300 species:[8][1]

Bothrocara brunneum
Lycodes turneri
Pachycara sp.
Zoarces viviparus

Characteristics

The body of eelpouts is relatively elongated and laterally compressed.[9] Their heads are relatively small and ovoid. Juveniles have a more rounded snout and relatively larger eye than adults.[9] Their scales are absent or very small.[10] The dorsal and anal fins are continuous down their bodies up to their caudal fin. They produce the pigment biliverdin, which turns their bones green. This feature has no apparent evolutionary function and is harmless.[11] Overall, there is no sexual dimorphism.[12]

Biology

Little is known about eelpout populations because they often slip through nets in sampling studies, and because some species live in inaccessibly deep habitats. Species for which trophic ecology has been documented are typically, if not always, benthic scavengers or predators.[11][13] At least one species has also adapted to able to breathe air when out of water.[11]

Timeline

QuaternaryNeogenePaleogeneHolocenePleist.MioceneOligoceneEocenePaleoceneAnarrhichthysAnarhichasQuaternaryNeogenePaleogeneHolocenePleist.MioceneOligoceneEocenePaleocene

References

  1. 1 2 3 Richard van der Laan; William N. Eschmeyer & Ronald Fricke (2014). "Family-group names of Recent fishes". Zootaxa. 3882 (2): 001–230. doi:10.11646/zootaxa.3882.1.1. PMID 25543675.
  2. ↑ Swainson, William (1839). On the Natural History and Classification of Fishes, Amphibians, and Reptiles. Vol. 2. London: Longman, Orme, Brown, Greene, & Longmans. pp. 82–83, 184, 283. doi:10.5962/bhl.title.62140.
  3. ↑ Kawahara, R.; Miya, M.; Mabuchi, K.; Lavoué, S.; Inoue, J.G.; Satoh, T.P.; Kawaguchi, A. & Nishida, M. (2008). "Interrelationships of the 11 gasterosteiform families (sticklebacks, pipefishes, and their relatives): a new perspective based on whole mitogenome sequences from 75 higher teleosts". Molecular Phylogenetics and Evolution. 46 (1): 224–36. doi:10.1016/j.ympev.2007.07.009. PMID 17709262.
  4. 1 2 J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. pp. 478–482. ISBN 978-1-118-34233-6.
  5. ↑ Ricardo Betancur-R; Edward O. Wiley; Gloria Arratia; et al. (2017). "Phylogenetic classification of bony fishes". BMC Evolutionary Biology. 17 (162): 162. doi:10.1186/s12862-017-0958-3. PMC 5501477. PMID 28683774.
  6. ↑ Anderson , M. E. and V. V . Fedorov (2004). "Family Zoarcidae Swainson 1839 — eelpouts" (PDF). California Academy of Sciences Annotated Checklists of Fishes. 34.
  7. ↑ Froese, Rainer, and Daniel Pauly, eds. (2022). "Zoarcidae" in FishBase. June 2022 version.
  8. 1 2 Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Zoarcidae". Catalog of Fishes. California Academy of Sciences. Retrieved 4 October 2022.
  9. 1 2 Anderson, M. Eric (1988-02-05). "Eucryphycus, a new genus of California eelpout (Teleostei: Zoarcidae) based on Maynea californica Starks and Mann, 1911". Proceedings of the California Academy of Sciences. 4th. 45 (5): 89-96 p. 91.
  10. ↑ "Family Zoarcidae: Eelpouts". Key to Fishes of the Puget Sound. Burke Museum. Retrieved 10 September 2022.
  11. 1 2 3 Froese, R.; D. Pauly (eds.). "Zoarces viviparus (Linnaeus, 1758), Eelpout". FishBase.
  12. ↑ Anderson, M. Eric (1989-12-20). "Review of the eelpout genus Pachycara Zugmayer, 1911 (Teleostei: Zoarcidae), with descriptions of six new species". Proceedings of the California Academy of Sciences. 4th. 46 (10): 221–242.
  13. ↑ Belman, Bruce W.; Anderson, M. Eric (May 18, 1979). "Aquarium Observations on Feeding by Melanostigma pammelas (Pisces: Zoarcidae)". Copeia. 1979 (2): 366–369. doi:10.2307/1443432. JSTOR 1443432.
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