---
title: "What the sources say about the Fangtooth | AnimalTracks.wiki"
description: "50 claims from the Fangtooth profile, each beside the words of the source that backs it."
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---

# What the sources say about the Fangtooth (*Anoplogaster cornuta*)

> 50 claims from the Fangtooth profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Fangtooth](https://animaltracks.wiki/animals/fangtooth/)

## Kierdorf et al. (2022). Dental structure and tooth attachment modes in the common fangtooth Anoplogaster cornuta (Valenciennes, 1833) (Actinopterygii; Trachichthyiformes; Anoplogastridae). PLOS ONE.

https://doi.org/10.1371/journal.pone.0272860

| The page says | The source says |
| :--- | :--- |
| reported to have the largest teeth of any marine fish for its head size | Relative to its head size, which accounts for about one-third of the maximum adult body length of about 16 to 17cm, Anoplogaster cornuta possesses the largest teeth of any marine fish (note: Kierdorf et al. attribute this to their ref [2], which is the ADW account (ADW puts it 'Relative to body size, they have the largest teeth of any marine species'), hence 'reported') |
| fangs so long an adult cannot fully close its mouth | The long anterior fang teeth of the oral jaws prevent adult individuals from completely closing their mouth |
| Fangs so long that the lower pair slide into pockets in the roof of its mouth | with the fangs of the lower jaw sliding into pockets in the roof of the mouth when it is partially closed |
| reportedly the largest teeth of any marine fish for its head size | Relative to its head size, which accounts for about one-third of the maximum adult body length of about 16 to 17cm, Anoplogaster cornuta possesses the largest teeth of any marine fish (note: attributed by the authors to ADW, their ref [2]) |
| An adult fangtooth's head takes up about a third of its maximum body length of about 16 to 17 centimetres | Relative to its head size, which accounts for about one-third of the maximum adult body length of about 16 to 17cm |
| Its long front fangs stop an adult from closing its mouth completely: when the jaws are partly shut, the lower fangs slide into pockets in the roof of the mouth | The long anterior fang teeth of the oral jaws prevent adult individuals from completely closing their mouth, with the fangs of the lower jaw sliding into pockets in the roof of the mouth when it is partially closed |
| A 2022 microscope study of two adults caught in the North Atlantic | Two adult specimens of Anoplogaster cornuta (total length of 12.0 and 13.5 cm, respectively) were caught in 2002 at depths between 680 and 708 meters during an expedition (M244) to the Irmiger and Greenland Sea (North Atlantic Ocean) (note: 2022 is the publication year; microscopy from 'using light- and scanning-electron microscopic techniques') |
| found every tooth made solely of orthodentin | All teeth were monocuspid, composed solely of orthodentin, and lacked a covering enameloid cap |
| the jaw teeth fused solid to the bone | The oral jaw teeth were transparent, non-depressible and firmly ankylosed to their respective dentigerous bone |
| It found no sign that the big jaw teeth had been replaced | No evidence for replacement of the large oral jaw teeth was found in the analyzed adult specimens |
| The teeth in the throat, by contrast, showed signs of replacement: empty sockets and small new teeth | In contrast to the oral jaw teeth, the pharyngeal teeth of Anoplogaster cornuta are replaced as is indicated by the presence of empty tooth loci and small, newly established teeth |
| Relative to the size of its head, the common fangtooth is reported to have the largest teeth of any fish in the sea | Relative to its head size, which accounts for about one-third of the maximum adult body length of about 16 to 17cm, Anoplogaster cornuta possesses the largest teeth of any marine fish (note: attributed by the authors to ADW, their ref [2], hence 'reported') |
| The genus holds two species, the common fangtooth (Anoplogaster cornuta) and the shorthorn fangtooth (Anoplogaster brachycera) | The two species within the genus are the common or longhorn fangtooth (or sabretooth) (Anoplogaster cornuta) and the shorthorn fangtooth (or sabretooth) (Anoplogaster brachycera) |
| Two Species, and a Case of Mistaken Identity | The two species within the genus are the common or longhorn fangtooth (or sabretooth) (Anoplogaster cornuta) and the shorthorn fangtooth (or sabretooth) (Anoplogaster brachycera) (note: 'mistaken identity' is the juveniles-as-separate-species history, claimed below from ADW) |
| Young common fangtooths carry long spines on the head and gill cover that shorthorns lack | Juveniles of the former species possess long temporal and preopercular spines that are missing in the latter |
| The lower jaw's fangs do not start growing until a young fish reaches about 2 centimetres long, the upper fangs wait until 5.3 centimetres, and only around 8 centimetres does a fangtooth begin to look like the adult it will become | The large anterior fang-like teeth start to develop in the lower jaw when the animals reach about 2 cm body length, and in the upper jaw at about 5.3 cm body length, and juveniles begin to resemble adults when attaining a body length of about 8 cm (note: 'until' and 'only' paraphrase 'start to develop ... when the animals reach') |
| Adults feed mainly on fish and shrimp, typically swallowed whole, and prey can reach a third of their own body size | Adult individuals mainly feed on fish and shrimps that are typically swallowed whole. Prey size of adults can reach one-third of their body size |
| In the two adults a 2022 study examined, fourteen: three on each side of the upper jaw and four on each side of the lower | Fourteen teeth were present in the oral jaws, with three teeth each on the left and right premaxilla and four teeth each on the left and right dentary |
| with the front tooth on each bone much larger than the rest | The anteriormost premaxillary and dentary teeth were considerably larger than the more posteriorly located ones |
| Each is fused to the bone and cannot fold back | The oral jaw teeth were transparent, non-depressible and firmly ankylosed to their respective dentigerous bone |
| Numerous small teeth on the gill arches presumably help hold on to small prey in a habitat where food is sparse | a firm ankylosis was observed in numerous small teeth located on the branchial arches. The function of these teeth is presumably to increase the tightness of the pharyngeal basket and thereby the retention of small prey items in a species living in a habitat with only sparse food supply |
| A fangtooth's fangs are so long that an adult cannot fully close its mouth: when the jaws partly shut, the lower pair slide into pockets in the roof | The long anterior fang teeth of the oral jaws prevent adult individuals from completely closing their mouth, with the fangs of the lower jaw sliding into pockets in the roof of the mouth when it is partially closed |

## Portner et al. (2023). Harnessing a mesopelagic predator as a biological sampler reveals taxonomic and vertical resource partitioning among three poorly known deep-sea fishes. Scientific Reports.

https://doi.org/10.1038/s41598-023-41298-9

| The page says | The source says |
| :--- | :--- |
| Young A. cornuta start out silvery gray | This size correlates with an ontogenetic change in coloration from the silvery gray of juveniles to the black or dark brown of adults |
| A 2023 study examined 91 juvenile fangtooth, weighing 0.6 to 22 grams, recovered from the stomachs of longnose lancetfish | We examined specimens sampled from the stomachs of longnose lancetfish, Alepisaurus ferox, to describe the diets and foraging behaviors of three common, but poorly known deep-sea fishes: the hammerjaw (Omosudis lowii, n = 79, 0.3-92 g), juvenile common fangtooth (Anoplogaster cornuta, n = 91, 0.6-22 g) (note: 2023 is the publication year) |
| caught on Hawaii-based longlines in the central North Pacific | Lancetfish stomachs were collected by federal fisheries observers in the Hawaiʻi-based longline fishery (note: central North Pacific (CNP) is the study area named throughout the paper) |
| They specialized on tiny crustaceans called hyperiid amphipods | Juvenile Anoplogaster specialize on hyperiid amphipods |
| one family, Phrosinidae, turned up in 86 percent of stomachs | exhibited a high degree of specialization on Phrosinidae (65% M ¯ ps , 86% FO ) (note: FO is 'the percent frequency of occurrence per predator'; the 65% figure the writer used is %M̄ps, mass computed only over stomachs that held Phrosinidae, so it was cut) |
| Their estimated mean foraging depth, about 200 metres, was the shallowest of the three species studied | Anoplogaster cornuta had the shallowest mean estimated foraging depth (GAM, intercept = 202.38 m, 95% CI [135.37, 269.39], p  < 0.001) (note: 202.38 m rounded; the three species are A. cornuta, Alepisaurus ferox and Omosudis lowii) |
| Young fangtooth also end up in the stomachs of longnose lancetfish | We examined specimens sampled from the stomachs of longnose lancetfish, Alepisaurus ferox, to describe the diets and foraging behaviors of three common, but poorly known deep-sea fishes |

## Anoplogaster cornuta (common sabertooth). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Anoplogaster_cornuta/

| The page says | The source says |
| :--- | :--- |
| Bathypelagic and mesopelagic open ocean worldwide, mostly 500 to 2,000 meters down, to a maximum of about 5,000 meters | is an exclusively marine species and exists from bathypelagic to mesopalagic depths ranging from 2 m to 4992 m below sea level; however, it is most common between 500 m and 2000 m. Adults are commonly captured at depths ranging from 75 to 5000 m |
| Fish and shrimp as adults, tiny drifting crustaceans as juveniles | Juveniles feed on crustaceans, while adults feed primarily on fish and shrimp (note: 'drifting' (epipelagic hyperiid amphipods) is from portner-2023: 'Many stomachs were full of epipelagic crustaceans') |
| large-eyed and spiny-headed | Juveniles have a long cephalic and preopercular spine. Their eyes are large |
| adults turn small-eyed, spineless and black or dark brown | adults do not have cephalic or preopercular spines. Their eyes are comparatively small (note: colour from portner-2023: 'to the black or dark brown of adults') |
| Juveniles and adults look so different that in the 1800s they were believed to be separate species | Adult and juvenile fangtooths are so morphologically dissimilar that they were believed to be separate species in the 1800s |
| With a full mouth, a fangtooth cannot pump water over its gills efficiently | When fangtooth’s have a full mouth, they are prohibited from efficiently pumping water over the gills for respiration |
| Instead it bulges out the opercula, the bony gill covers, exposing the gill arches | its opercula are greatly distended, which visibly exposes all of the gill arches |
| fans water over them from behind with its pectoral fins until the prey has been swallowed | it subsequently uses its pectoral fins to fan seawater over the gills from behind (note: 'until the prey has been swallowed' from 'This species maintains opercular distension while handling its prey, ceasing only after prey has been swallowed') |
| Anoplogaster cornuta lives worldwide in tropical, temperate and subarctic seas | found worldwide in tropical to temperate and subartctic seas |
| most often between 500 and 2,000 metres down, though adults have been caught as deep as 5,000 metres | it is most common between 500 m and 2000 m. Adults are commonly captured at depths ranging from 75 to 5000 m |
| It is stenothermic, adapted to a narrow band of 4 to 6°C | Anoplogaster cornuta is stenothermic and is adapted to temperatures between 4°C and 6ºC |
| Its dark brown to black colouring likely lowers the risk of being eaten where little or no sunlight reaches | Their dark brown to black color likely reduces predation risk at depths with little to no sunlight penetration |
| Fangtooth are not bioluminescent, so they make no light of their own. Adults can live deeper than sunlight reaches | Sunlight does not penetrate to bathypelagic depths at which adults may be found, and they are not bioluminescent |
| their eyes are comparatively small | Their eyes are comparatively small |
| at those depths the eyes are unlikely to be of much use | Thus, it is unlikely that their eyes are of much necessity at greater depths |
| They are thought to spawn from June to August | Fangtooths are thought to breed from June to August |
| laying eggs that hatch into planktonic (drifting) larvae, and the parents give no care | Fangtooths are oviparous and have planktonic larvae. There is no parental care |
| Little else is known of how the species reproduces | Little else is known of reproduction in this species |
| Tuna, including albacore, and marlin are listed as major predators | Major predators of Anoplogaster cornuta include tuna (e.g., albacore), and marlin |
| dangerLevel: Low | There are no known adverse effects of Anoplogaster cornuta on humans. |

## Iwamoto (2015). Anoplogaster cornuta. The IUCN Red List of Threatened Species 2015: e.T18123960A21910070.

https://doi.org/10.2305/iucn.uk.2015-4.rlts.t18123960a21910070.en

| The page says | The source says |
| :--- | :--- |
| The IUCN lists the species as Least Concern | IUCN Red List category: Least Concern (LC) (note: category read through GBIF's copy of the Red List, since iucnredlist.org refuses scripts) |