The bony-eared assfish (Acanthonus armatus) is a bathypelagic species of cusk-eel found in tropical and sub-tropical oceans at depths of from 1,171 to 4,415 metres (3,842 to 14,485 ft). It has been found as far north as Queen Charlotte Sound off British Columbia's coast.[7] This species grows to a length of 37.5 centimetres (14.8 in) SL.[6] The larvae are similar in overall form to the related gargoyle cusk, but have elongated 3rd, 4th, and 5th pectoral-fin rays.[8]
| Bony-eared assfish Temporal range:
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|---|---|
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| Specimen from north of New Guinea[1] | |
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| Specimen from south of Panama[2] | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Ophidiiformes |
| Family: | Ophidiidae |
| Subfamily: | Neobythitinae |
| Genus: | Acanthonus Günther, 1878 |
| Species: | A. armatus
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| Binomial name | |
| Acanthonus armatus | |
| Synonyms[5][6] | |
The bony-eared assfish may have the smallest brain-to-body weight ratio of any vertebrate.[9]
Like many other creatures that dwell in the depths of the sea, assfish are soft and flabby with a light skeleton. This is likely to have resulted from a lack of food and the high pressures which accompany living at such a depth, making it difficult to generate muscle and bone.[10]
Etymology
editThe type specimen was an 11.5-inch (29 cm) individual taken by the Challenger expedition (1872–1876) north of New Guinea at a depth of 1,075 fathoms (6,450 ft; 1,966 m). It was described in 1878 by German ichthyologist Albert Günther, who gave the species its scientific name.[4] Armatus means "armed" in Latin, likely chosen because the fish sports spines off the tip of the nose and the gills. This also perhaps accounts for the "bony-eared" part, according to Gavin Hanke, curator of vertebrate zoology at the Royal British Columbia Museum. Akanthos is Ancient Greek for "prickly", and onus could either mean "hake, a relative of cod", Hanke says, "or a donkey". Adam Summers, associate director at the Friday Harbor Laboratories at the University of Washington, concurs, saying onus could easily read "as a homonym of the Greek word for ass".[10]
References
edit- ^ Günther, Albert (1887). "Acanthonus armatus". Report on the Deep-Sea Fishes collected by H.M.S. Challenger during the years 1873-1876. Report on the Scientific Results of the Voyage of H.M.S. Challenger During the Years 1873–76. Vol. Zoology—Vol. XXII. pp. 117–118, Pl. 34, fig. A.
- ^ a b Garman, S. (1899). "Reports on an exploration off the west coasts of Mexico, Central and South America, and off the Galapagos Islands, in charge of Alexander Agassiz, by the U. S. Fish Commission steamer Albatross, during 1891, Lieut. Commander Z. L. Tanner, U. S. N., Commanding. XXVI. The Fishes". Memoirs of the Museum of Comparative Zoölogy, at Harvard College. 24: 170–171, Pl. F, Fig 3.
- ^ Knudsen, S. (2015). "Acanthonus armatus". IUCN Red List of Threatened Species. 2015: e.T190201A60796787. doi:10.2305/IUCN.UK.2015-4.RLTS.T190201A60796787.en. Retrieved 19 November 2021.
- ^ a b Günther, Albert (1878). "Preliminary Notices of Deep-Sea Fishes collected during the Voyange of H.M.S. 'Challenger'". The Annals and Magazine of Natural History. 2 (7): 22–23.
- ^ Nielsen, Jørgen G. (1965). "On the genera Acanthomus and Typhlomus (Pisces, Brotulidae)" (PDF). Galathea Report. 8: 32–48.
- ^ a b Froese, Rainer; Pauly, Daniel (eds.). "Acanthonus armatus". FishBase. January 2014 version.
- ^ Fuhrmann, Mike (14 January 2016). "Assfish goes on display at the Royal B.C. Museum in Victoria". CBC News. Retrieved 15 January 2016.
- ^ Girard, Matthew G.; Nonaka, Ai; Baldwin, Carole C.; Johnson, G. David (2024). "Discovery and description of elaborate larval cusk-eels and the relationships among Acanthonus, Tauredophidium, and Xyelacyba (Teleostei: Ophidiidae)". Early Life History and Biology of Marine Fishes: Research inspired by the work of H Geoffrey Moser: 20–42. doi:10.7755/pp.24.3.
- ^ Fine, M. L.; Horn, M. H.; Cox, B. (23 March 1987). "Acanthonus armatus, a deep-sea teleost fish with a minute brain and large ears". Proceedings of the Royal Society B: Biological Sciences. 230 (1259): 257–265. Bibcode:1987RSPSB.230..257F. doi:10.1098/rspb.1987.0018. ISSN 0080-4649. JSTOR 36061. PMID 2884671. S2CID 19183523.
- ^ a b Langley, Liz (2016-03-12). "What'd You Call Me? Meet the Bony-Eared Assfish". National Geographic. Archived from the original on January 14, 2022. Retrieved 25 April 2022.
