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{{Redirect|Elephant nose|the proboscis of an elephant|Elephant#Trunk{{!}}Elephant § Trunk}}
{{Short description |Species of fish}}
{{Redirect |Elephant nose |the proboscis of an elephant |Elephant#Trunk{{!}}Elephant § Trunk}}
{{Speciesbox
{{Taxobox
| image = Gnathonemus petersii.jpg
| name = Elephantnose fish
| image_caption = Elephantnose fish
| image = Gnathonemus petersii.jpg
| taxon = Gnathonemus petersii
| image_caption = Elephantnose fish
| authority = ([[Albert Günther |Günther]], 1862)
| regnum = [[Animal]]ia
| status = LC
| phylum = [[Chordate|Chordata]]
| status_system = IUCN3.1
| classis = [[Actinopterygii]]
| synonyms = *''Gnathonemus brevicaudatus'' {{small |Pellegrin, 1919}}
| ordo = [[Osteoglossiformes]]
*''Mormyrus petersii'' {{small |Günther, 1862}}
| familia = [[Mormyridae]]
| synonyms_ref = <ref>{{ITIS | id = 161918 | taxon = ''Gnathonemus petersii'' | access-date=July 3, 2007 }}</ref>
| genus = ''[[Gnathonemus]]''
| species = '''''G. petersii'''''
| binomial = ''Gnathonemus petersii''
| binomial_authority = ([[Albert Günther|Günther]], 1862)
| status = LC
| status_system = IUCN3.1
| synonyms = *''Gnathonemus brevicaudatus'' {{small|Pellegrin, 1919}}
*''Mormyrus petersii'' {{small|Günther, 1862}}
| synonyms_ref = <ref>{{ITIS | id = 161918 | taxon = ''Gnathonemus petersii'' | accessdate=July 3, 2007 }}</ref>
}}
}}
'''Peters's elephant-nose fish''' (''Gnathonemus petersii'') is an African freshwater [[Mormyridae |elephantfish]] in the genus ''[[Gnathonemus]]''. Other names in English include '''elephantnose fish''', '''long-nosed elephant fish''', and '''Ubangi mormyrid''', after the [[Ubangi River]]. The [[Latin]] name {{lang |la |petersii}} is probably for the German naturalist [[Wilhelm Peters]]. The fish uses [[electrolocation]] to find prey, and has the largest brain-to-body oxygen use ratio of all known vertebrates (around 0.6).<ref name=Nilsson1996>Nilsson G (1996) [http://jeb.biologists.org/cgi/content/abstract/199/3/603 "Brain and body oxygen requirements of Gnathonemus petersii, a fish with an exceptionally large brain"] ''Journal of Experimental Biology'', '''199'''(3): 603–607. [http://www.bio.uio.no/genfys/PDFfiler/GN/JEB199,603.pdf Download]</ref>


== Description ==
[[File:Gnathonemus petersii (Günther, 1862).en2.jpg|thumb|245px|right|The elephantnose fish is a [[weakly electric fish]] which generates an electric field with its [[Electric organ (biology)|electric organ]] and then processes the returns from its [[electroreceptor]]s to locate nearby objects.<ref>Von der Emde, G. (1999). "Active electrolocation of objects in weakly electric fish". ''Journal of Experimental Biology'', '''202''' (10): 1205–1215. [http://jeb.biologists.org/content/202/10/1205.full.pdf+html Full text]</ref>]]


Peters's elephantnose fish is native to the rivers of [[West Africa |West]] and [[Central Africa]], in particular the lower [[Niger River]] basin, the [[Ogun River]] basin and the upper [[Chari River]]. It prefers muddy, slowly moving rivers and pools with cover such as submerged branches. The fish is a dark brown to black in colour, laterally compressed (averaging {{cvt |23-25 |cm}}), with a rear dorsal fin and anal fin of the same length. Its caudal or tail fin is forked. It has two stripes on its lower pendicular. Its most striking feature, as its names suggest, is a trunk-like protrusion on the head. This is not actually a nose, but a sensitive extension of the mouth, that it uses for [[self-defense]], [[communication]], [[navigation]], and finding worms and insects to eat. This organ, called the Schnauzenorgan,<ref>{{Cite journal |last1=Engelmann |first1=Jacob |last2=Nöbel |first2=Sabine |last3=Röver |first3=Timo |last4=Emde |first4=Gerhard von der |date=2009-09-22 |title=The Schnauzenorgan-response of Gnathonemus petersii |journal=Frontiers in Zoology |volume=6 |issue=1 |pages=21 |doi=10.1186/1742-9994-6-21 |issn=1742-9994 |pmc=2760544 |pmid=19772622 |doi-access=free }}</ref> is covered in [[Electroreception |electroreceptors]], as is much of the rest of its body. The elephantnose uses a weak [[electric field]], which it generates with specialized cells called electrocytes, which evolved from muscle cells, to find food, to navigate in dark or turbid waters, and to find a mate. Peters's elephantnose fish live to about 6–10 years.
'''Peters' elephant-nose fish''' (''Gnathonemus petersii'') is an African freshwater [[Mormyridae|elephantfish]] in the genus ''[[Gnathonemus]]''. Other names in English include '''elephantnose fish''', '''long-nosed elephant fish''', and '''Ubangi mormyrid''', after the [[Ubangi River]]. As the Latin name ''petersii'' confirms it is named after someone called "Peters" (probably [[Wilhelm Peters]]), although the apostrophe is often misplaced and the common name given as "Peter's elephantnose fish". It uses [[electrolocation]] to find prey, and has the largest brain-to-body oxygen use ratio of all known vertebrates (around 0.6).<ref name=Nilsson1996>Nilsson G (1996) [http://jeb.biologists.org/cgi/content/abstract/199/3/603 "Brain and body oxygen requirements of Gnathonemus petersii, a fish with an exceptionally large brain"] ''Journal of Experimental Biology'', '''199'''(3): 603-607. [http://www.bio.uio.no/genfys/PDFfiler/GN/JEB199,603.pdf Download]</ref>


== Electrolocation ==
==Description==
[[Image:MormyrusJury.jpg|thumb|left|Illustration (1864), the upper is Peters' elephantnose fish. The lower is a [[Campylomormyrus tamandua|worm-jawed mormyrid]] (''Campylomormyrus tamandua'')]]


[[File:Gnathonemus petersii (Günther, 1862).en2.jpg|thumb|The elephantnose fish is a [[weakly electric fish]] which generates an electric field with its [[Electric organ (biology)|electric organ]] and then processes the returns from its [[electroreceptor]]s to locate nearby objects.<ref name="Von der Emde 1999">Von der Emde, G. (1999). "Active electrolocation of objects in weakly electric fish". ''Journal of Experimental Biology'', '''202''' (10): 1205–1215. [http://jeb.biologists.org/content/202/10/1205.full.pdf+html Full text]</ref>]]
Peters' elephantnose fish are native to the rivers of [[West Africa|West]] and [[Central Africa]], in particular the lower [[Niger River]] basin, the [[Ogun River]] basin and in the upper [[Chari River]]. It prefers muddy, slowly moving rivers and pools with cover such as submerged branches. It is a dark brown to black in colour, laterally compressed (averaging 23&ndash;25&nbsp;cm), with a rear dorsal fin and anal fin of the same length. Its caudal or tail fin is forked. It has two stripes on its lower pendicular. Its most striking feature, as its names suggest, is a trunk-like protrusion on the head. This is not actually a nose, but a sensitive extension of the mouth, that it uses for [[self-defense]], [[communication]], [[navigation]], and finding worms and insects to eat. This organ, called the Schnauzenorgan<ref>{{Cite journal|last=Engelmann|first=Jacob|last2=Nöbel|first2=Sabine|last3=Röver|first3=Timo|last4=Emde|first4=Gerhard von der|date=2009-09-22|title=The Schnauzenorgan-response of Gnathonemus petersii|journal=Frontiers in Zoology|volume=6|issue=1|pages=21|doi=10.1186/1742-9994-6-21|issn=1742-9994|pmc=2760544|pmid=19772622}}</ref>, is covered in [[Electroreception|electroreceptors]], as is much of the rest of its body. The elephantnose uses a weak [[electric field]], which it generates with specialized cells called electrocytes, which evolved from muscle cells, to find food, to navigate in dark or turbid waters, and to find a mate. Peters' elephantnose fish live to about 6–10 years, but there are reports of them living even longer.


{{further|Electroreception}}
==In the aquarium==
{{manual|date=November 2014}}
Peters' elephantnose fish is among the most commonly available Mormyrid in [[aquarium]] stores in the USA. In the aquarium it is timid, preferring a heavily planted environment with subdued lighting and thrives in a tank of more than 200 liters. Ideally, a pipe or hollow log should be provided and the optimum [[Substrate (aquarium)|substrate]] is some soft sand that allows the fish to sift through it with its delicate extended lip. It feeds on small worms([[Glycera (genus)|bloodworm]]s being the most common) and aquatic invertebrates such as mosquito larvae, but in the aquarium will accept frozen or flake food. How peaceful an elephantnose fish is can depend on the individual; some are quite aggressive with other species, while others are retiring. They may be kept in a community aquarium with peaceful species who share their water preferences. However, unless kept in an aquarium of over 400 liters, it is unwise to keep more than one elephantnose fish as they can be territorial. The elephantnose is suggested to be kept in the following conditions: [[pH]] of 6.8 to 7.2, water temperature 26C to 28C, and water of medium [[hard water|hardness]].


The elephant nose fish is [[Weakly electric fish|weakly electric]], meaning that it can detect moving prey and worms in the substrate by generating brief electric pulses with the [[Electric organ (biology)|electric organ]] in its tail. The [[Electroreception|electroreceptors]] around its body are sensitive enough to detect the different distortions of the electric field made by objects that conduct or resist electricity.<ref name="Von der Emde 1999"/> The weak electric fields generated by this fish can be made audible by placing two electrodes in the fish tank, connected to an audio amplifier or a [[piezoelectric]] earbud.<ref>{{cite journal |last1=P.R |first1=Møller |title=Book reviews |journal=Reviews in Fish Biology and Fisheries |date=1 June 1996 |volume=6 |issue=2 |pages=251–257 |doi=10.1007/BF00182347 |url=https://link.springer.com/article/10.1007/BF00182347 |access-date=28 November 2023 |language=en |issn=1573-5184}}</ref>
The weak electrical impulses generated by this fish can be made audible by placing two electrodes in the fish tank that are then hooked up to an audio amplifier or a [[piezoelectric]] earbud. The elephant nose fish can use its electosensing to detect moving prey and worms in the substrate.


== In the aquarium ==
Although the elephant nose fish was once thought to have poor eyesight, it is now known to have good low light vision. Its eyes use a combination of photonic crystals, parabolic mirrors and a clustered arrangement of rods and cones.<ref>http://www.sciencemag.org/content/suppl/2012/06/27/336.6089.1730-b.DC1/SciencePodcast_120629.pdf</ref>

[[File:Peters' elephantnose fish 2014 11 08.ogv|thumb|In captivity]]
{{more citations needed |section |date=September 2021}}

Peters's elephantnose fish is one of the most commonly available [[mormyrid |freshwater elephantfish]] in [[aquarium]] stores in the [[United States]]. In the aquarium it is timid, preferring a heavily planted environment with subdued lighting, and thrives in a tank of more than {{convert |200 |l}}; favourable additions to the fish's aquarium environment are a pipe or hollow log, alongside soft, sandy [[substrate (aquarium) |substrate]], allowing the fish to sift through it with its delicate extended lip.

The fish feeds on small worms ([[Glycera (genus) |bloodworm]]s being the most common) and aquatic invertebrates such as mosquito larvae, but will accept frozen or flake food. Elephantnose fish are typically kept in water of medium [[hard water |hardness]] with a [[pH]] of 6.8 to 7.2 and a temperature of between {{cvt |26-28 |°C}}.

Elephantnose fish, though typically docile when kept in captivity, can be aggressive towards other species of fish, though some fare well in community aquarium environments. However, unless kept in an aquarium of over {{cvt |400 |l}}, elephantnose fish are aggressively territorial towards members of their own species. For this reason owners have been recommended not to keep more than one in captivity.

The elephantnose fish has good low light vision. Its eyes use a combination of photonic crystals, parabolic mirrors and a clustered arrangement of rods and cones.<ref>{{Cite web |url=https://www.science.org/action/cookieAbsent |title=AAAS |website=Science.org |access-date=1 December 2021}}</ref>

The species has never been bred in captivity, meaning that all aquarium available specimens are wild-caught.<ref>{{cite web |url= https://www.aquariumindustries.com.au/wp-content/uploads/2015/03/Elephant-Nose.pdf'' | title=Aquarium availability |accessdate=3 January 2022 |work=Aquarium industries}}</ref> This requires the owner to maintain specific water parameters if the fish is to thrive.


==See also==
==See also==
Line 48: Line 52:


==External links==
==External links==
{{Commons category|Gnathonemus petersii}}
{{Commons category |Gnathonemus petersii}}
{{Wikispecies|Gnathonemus petersii}}
{{Wikispecies |Gnathonemus petersii}}
* Peter Cain and Sapna Malwal, Landmark use and development of navigation behaviour in the weakly electric fish ''Gnathonemus petersii'' (Mormyridae; Teleostei), Journal of Experimental Biology, 205, 3915-3923 (2002), [http://jeb.biologists.org/cgi/content/full/205/24/3915]
* Peter Cain and Sapna Malwal, Landmark use and development of navigation behaviour in the weakly electric fish ''Gnathonemus petersii'' (Mormyridae; Teleostei), Journal of Experimental Biology, 205, 3915–3923 (2002), [http://jeb.biologists.org/cgi/content/full/205/24/3915 Landmark use and development of navigation behaviour in the weakly electric fish Gnathonemus petersii (Mormyridae; Teleostei)]
* [http://news.bbc.co.uk/2/shared/spl/hi/pop_ups/07/sci_nat_enl_1187693729/html/1.stm Photo] (BBC News)
* [http://news.bbc.co.uk/2/shared/spl/hi/pop_ups/07/sci_nat_enl_1187693729/html/1.stm Photo] (BBC News)
* [http://sci-toys.com/scitoys/scitoys/biology/electric_fish/electric_fish.html Sci-toys.com instructions on making elephant nose electrical emissions audible]
* [http://sci-toys.com/scitoys/scitoys/biology/electric_fish/electric_fish.html Sci-toys.com instructions on making elephant nose electrical emissions audible]


{{Taxonbar|from=Q945393}}
{{Taxonbar |from=Q945393}}


[[Category:Mormyridae]]
[[Category:Mormyridae]]
[[Category:Weakly electric fish]]
[[Category:Weakly electric fish]]
[[Category:Fish described in 1862]]
[[Category:Fish described in 1862]]
[[Category:Taxa named by Albert Günther]]

Latest revision as of 01:07, 15 November 2024

Peters's elephantnose fish
Elephantnose fish
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Osteoglossiformes
Family: Mormyridae
Genus: Gnathonemus
Species:
G. petersii
Binomial name
Gnathonemus petersii
(Günther, 1862)
Synonyms[1]
  • Gnathonemus brevicaudatus Pellegrin, 1919
  • Mormyrus petersii Günther, 1862

Peters's elephant-nose fish (Gnathonemus petersii) is an African freshwater elephantfish in the genus Gnathonemus. Other names in English include elephantnose fish, long-nosed elephant fish, and Ubangi mormyrid, after the Ubangi River. The Latin name petersii is probably for the German naturalist Wilhelm Peters. The fish uses electrolocation to find prey, and has the largest brain-to-body oxygen use ratio of all known vertebrates (around 0.6).[2]

Description

[edit]

Peters's elephantnose fish is native to the rivers of West and Central Africa, in particular the lower Niger River basin, the Ogun River basin and the upper Chari River. It prefers muddy, slowly moving rivers and pools with cover such as submerged branches. The fish is a dark brown to black in colour, laterally compressed (averaging 23–25 cm (9.1–9.8 in)), with a rear dorsal fin and anal fin of the same length. Its caudal or tail fin is forked. It has two stripes on its lower pendicular. Its most striking feature, as its names suggest, is a trunk-like protrusion on the head. This is not actually a nose, but a sensitive extension of the mouth, that it uses for self-defense, communication, navigation, and finding worms and insects to eat. This organ, called the Schnauzenorgan,[3] is covered in electroreceptors, as is much of the rest of its body. The elephantnose uses a weak electric field, which it generates with specialized cells called electrocytes, which evolved from muscle cells, to find food, to navigate in dark or turbid waters, and to find a mate. Peters's elephantnose fish live to about 6–10 years.

Electrolocation

[edit]
The elephantnose fish is a weakly electric fish which generates an electric field with its electric organ and then processes the returns from its electroreceptors to locate nearby objects.[4]

The elephant nose fish is weakly electric, meaning that it can detect moving prey and worms in the substrate by generating brief electric pulses with the electric organ in its tail. The electroreceptors around its body are sensitive enough to detect the different distortions of the electric field made by objects that conduct or resist electricity.[4] The weak electric fields generated by this fish can be made audible by placing two electrodes in the fish tank, connected to an audio amplifier or a piezoelectric earbud.[5]

In the aquarium

[edit]
In captivity

Peters's elephantnose fish is one of the most commonly available freshwater elephantfish in aquarium stores in the United States. In the aquarium it is timid, preferring a heavily planted environment with subdued lighting, and thrives in a tank of more than 200 litres (44 imp gal; 53 US gal); favourable additions to the fish's aquarium environment are a pipe or hollow log, alongside soft, sandy substrate, allowing the fish to sift through it with its delicate extended lip.

The fish feeds on small worms (bloodworms being the most common) and aquatic invertebrates such as mosquito larvae, but will accept frozen or flake food. Elephantnose fish are typically kept in water of medium hardness with a pH of 6.8 to 7.2 and a temperature of between 26–28 °C (79–82 °F).

Elephantnose fish, though typically docile when kept in captivity, can be aggressive towards other species of fish, though some fare well in community aquarium environments. However, unless kept in an aquarium of over 400 L (88 imp gal; 110 US gal), elephantnose fish are aggressively territorial towards members of their own species. For this reason owners have been recommended not to keep more than one in captivity.

The elephantnose fish has good low light vision. Its eyes use a combination of photonic crystals, parabolic mirrors and a clustered arrangement of rods and cones.[6]

The species has never been bred in captivity, meaning that all aquarium available specimens are wild-caught.[7] This requires the owner to maintain specific water parameters if the fish is to thrive.

See also

[edit]

Notes

[edit]
  1. ^ "Gnathonemus petersii". Integrated Taxonomic Information System. Retrieved July 3, 2007.
  2. ^ Nilsson G (1996) "Brain and body oxygen requirements of Gnathonemus petersii, a fish with an exceptionally large brain" Journal of Experimental Biology, 199(3): 603–607. Download
  3. ^ Engelmann, Jacob; Nöbel, Sabine; Röver, Timo; Emde, Gerhard von der (2009-09-22). "The Schnauzenorgan-response of Gnathonemus petersii". Frontiers in Zoology. 6 (1): 21. doi:10.1186/1742-9994-6-21. ISSN 1742-9994. PMC 2760544. PMID 19772622.
  4. ^ a b Von der Emde, G. (1999). "Active electrolocation of objects in weakly electric fish". Journal of Experimental Biology, 202 (10): 1205–1215. Full text
  5. ^ P.R, Møller (1 June 1996). "Book reviews". Reviews in Fish Biology and Fisheries. 6 (2): 251–257. doi:10.1007/BF00182347. ISSN 1573-5184. Retrieved 28 November 2023.
  6. ^ "AAAS". Science.org. Retrieved 1 December 2021.
  7. ^ "Aquarium availability". Aquarium industries. Retrieved 3 January 2022.

References

[edit]
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