# Telescopefish > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Telescopefish > Markdown URL: https://mediated.wiki/source/Telescopefish.md > Source: https://en.wikipedia.org/wiki/Telescopefish > Source revision: 1355875010 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Genus of fishes}} {{Distinguish|Telescope fish}} {{More citations needed|date=December 2021}} {{Automatic taxobox | name = Telescopefish | image = gigantura chuni.png | image_caption = ''[Gigantura chuni](/source/Gigantura_chuni)'' | taxon = Gigantura | authority = [A. B. Brauer](/source/August_Bernhard_Brauer), 1901 | subdivision_ranks = Species | subdivision = }} '''Telescopefish''' are small, deep-sea [aulopiform fish](/source/Aulopiformes) classified in the small [family](/source/Family_(taxonomy)) '''Giganturidae'''. Telescopefish can be found at the depths of 2000 meters under water. The two species are within the [genus](/source/genus) '''''Gigantura'''''. Though rarely captured, they are found in cold, deep tropical to subtropical waters worldwide. The common name of these [fish](/source/fish) is related to their bizarre, tubular [eye](/source/eye)s. The genus name ''Gigantura'' refers to the [Gigantes](/source/Gigantes), a race of [giant](/source/giant)s in [Greek mythology](/source/Greek_mythology)—coupled with the suffix ''oura'', meaning 'tail', thus ''Gigantura'' refers to the greatly elongated, ribbon-like lower half of the tailfin that may account for over half of the total body length. ==Species== The currently recognized species in this genus are:{{FishBase genus | genus = Gigantura| month = April | year = 2012}} * ''Gigantura chuni'' [A. B. Brauer](/source/August_Bernhard_Brauer), 1901 (gigantura) * ''Gigantura indica'' A. B. Brauer, 1901 (telescopefish) == Description == The Giganturidae are slender, slightly tapered fish with large heads dominated by large, forward-pointing, [telescoping](/source/telescope) eyes with large [lenses](/source/Lens_(anatomy)). Their heads end in short, pointed snouts. The highly extensile mouth is lined with sharp, slightly recurved and depressible teeth and it extends well past the eyes. The body lacks [scale](/source/scale_(zoology))s, but is covered in easily abraded, silvery [guanine](/source/guanine), which imparts a greenish to purplish [iridescence](/source/iridescence) in life. The [gas bladder](/source/gas_bladder) is absent and the [stomach](/source/stomach) is highly distensible. The transparent [fin](/source/fin)s are [spineless](/source/Spine_(zoology)); the deeply forked and hypocercal [caudal fin](/source/caudal_fin) is most striking, with the lower lobe extended to a length exceeding that of the body. The [pectoral fin](/source/pectoral_fin)s are large (about 30–42 [rays](/source/Fish_fin)), situated above the [gill](/source/gill) opening, and inserted horizontally. The [anal fin](/source/anal_fin) (about 8–14 rays) and single [dorsal fin](/source/dorsal_fin) (about 16–19 rays) are both situated far back of the head. The [pelvic fin](/source/pelvic_fin)s and [adipose fin](/source/adipose_fin) are absent. Also absent are the [premaxilla](/source/premaxilla), [orbitosphenoid](/source/orbitosphenoid), [parietal](/source/%3Awikt%3Aparietal), [symplectic](/source/Symplectic_bone), [posttemporal](/source/posttemporal), and [supratemporal](/source/supratemporal) [bone](/source/bone)s, the [gill raker](/source/gill_raker)s, and the branchiostegal rays. The loss of these structures is attributed to [neoteny](/source/neoteny); that is, the retention of [larva](/source/larva)l characteristics. ''[Gigantura indica](/source/Gigantura_indica)'' is the larger of the two species at about {{convert|20.3|cm|in|0}} standard length (a measurement excluding the caudal fin). However, ''[Gigantura chuni](/source/Gigantura_chuni)'' (at about {{convert|15.6|cm|in}} standard length) is slightly more robust in build. Both species within the genus have been recently observed in Australian waters and have a very similar species distribution.{{cite thesis |id={{ProQuest|2731484561}} |last1=Richarte |first1=Darlene Renee |date=2022 |title=Species Distribution Modeling of Telescopefishes (Actinopterygii: Giganturidae) }}{{page needed|date=July 2024}} == Life history == Telescopefish are presumed to be solitary, active [predator](/source/predator)s, frequenting the [mesopelagic](/source/mesopelagic) to [bathypelagic](/source/bathypelagic) zones of the water column, from {{convert|500|to|3,000|m|sigfig=3}}. By using their tubular, large-lensed eyes—which are adapted for optimal binocular light collection, at the expense of lateral vision—telescopefish are likely able to spy their prey's weak [bioluminescence](/source/bioluminescence) from a distance, as well as (by looking skyward) resolve the outlined silhouettes of prey against the gloom above. Their eyes may also help telescopefish to better judge distance of prey; these visual adaptations are typical of deep-sea fish ([barrel-eye](/source/barrel-eye), [tube-eye](/source/tube-eye)). Common prey include [bristlemouth](/source/bristlemouth)s, [lanternfish](/source/lanternfish), and [barbeled dragonfish](/source/barbeled_dragonfish). Owing to the telescopefishes' highly extensile jaws and distensible stomachs, they are able to swallow prey larger than themselves; this is also a common adaptation to life in the lean depths ([sabertooth fish](/source/sabertooth_fish), [black seadevil](/source/black_seadevil)). Telescopefish participate in the [diel vertical migration](/source/diel_vertical_migration) in which [mesopelagic fish](/source/mesopelagic_fish) migrate to the surface at night to feed before returning to the depths to shelter during the day.{{Cite web |last=Donovan |first=Moira |date=November 21, 2023 |title=All the Fish We Cannot See |url=https://hakaimagazine.com/features/all-the-fish-we-cannot-see/ |access-date=2024-02-19 |website=Hakai Magazine |language=en}} Much less is known of their [reproductive](/source/reproduction) habits. They are presumed to be nonguarding pelagic [spawn](/source/Spawn_(biology))ers, releasing [eggs](/source/roe) and [sperm](/source/sperm) indiscriminately into the water. The fertilized eggs are buoyant and become incorporated into the [zooplankton](/source/zooplankton), wherein they and the larvae remain—likely at much shallower depths than the adults—until [metamorphosis](/source/metamorphosis) into juvenile or adult form. == See also == * [List of fish families](/source/List_of_fish_families) * [List of fish common names](/source/List_of_fish_common_names) == References == {{Reflist}} ==Further reading== * {{cite journal |last1=Konstantinidis |first1=Peter |last2=Johnson |first2=G. David |title=Osteology of the telescopefishes of the genus Gigantura (Brauer, 1901), Teleostei: Aulopiformes |journal=Zoological Journal of the Linnean Society |date=September 2016 |doi=10.1111/zoj.12469 }} * {{cite journal |doi=10.11369/jji1950.55.127 |date=2008 |volume=55 |last1=冨山 |first1=晋一 |last2=福井 |first2=篤. |last3=北河 |first3=康之 |last4=沖山 |first4=宗雄 |title=日本近海に出現するボウエンギョ科魚類コガシラボウエンギョ (新称) ''Gigantura indica'' |trans-title=Records of telescope fish, ''Gigantura indica'' (Aulopiformes: Giganturidae), around Japan |journal=魚類学雑誌 |language=ja }} * {{cite book |doi=10.1016/B978-0-12-409548-9.11212-6 |chapter=Mesopelagic Fish |title=Encyclopedia of Ocean Sciences |date=2019 |last1=Staby |first1=Arved |last2=Salvanes |first2=Anne G.V. |pages=283–289 |isbn=978-0-12-813082-7 }} {{Taxonbar|from=Q14721240}} Category:Giganturidae --- Adapted from the Wikipedia article [Telescopefish](https://en.wikipedia.org/wiki/Telescopefish) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Telescopefish?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.