Threetooth puffer

Triodon macropterus (common name the threetooth puffer and the black-spot keeled pufferfish) is a tetraodontiform fish, the only living species in the genus Triodon and family Triodontidae.[1][2] Other members of the family are known from fossils stretching back to the Eocene.[3] The threetooth puffer was first scientifically described by René Lesson in 1831 and is recognizable for its large belly flap which has the ability to blend into the body when fully retracted.[1][2]

Threetooth puffer
Temporal range: Eocene–Recent
Triodon macropterus JNC2989.JPG
Triodon macropterus, with extended belly flap
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Tetraodontiformes
Family: Tetraodontidae
Bleeker, 1865-69
Genus: Triodon
G. Cuvier, 1829
T. macropterus
Binomial name
Triodon macropterus
Lesson, 1831


The name Triodon macropterus comes from the Ancient Greek τρι- (tri-, meaning 'three') and ὀδούς (or ὀδών, odoús, odṓn, meaning 'tooth'), and refers to the three fused teeth that make up a beak-like structure.[2]

Distribution and ecologyEdit

The threetooth puffer is native to the Indo-Pacific, where it is found mainly around Australia and off the coast of Asia at depths from 30–300 m (98–984 ft).[2][4][5][6][7] Its habitat is pelagic, consisting of continental shelves, slopes, seamounts, and knolls.[8][7]

Diet and digestionEdit

Little is known about the diet of the threetooth puffer. However, a dissection of the stomach of a caught juvenile specimen uncovered traces of mysid crustacean, foraminifera, echinoids, and sponges.[9]

The intestinal tract of the threetooth puffer (the esophagus, stomach, and intestines) is lined with several papillae, protrusions of the gut lumen.[9] After the stomach, the tract branches off into a specialized sac-like compartment called Tyler's Pouch.[9] Within the Tyler's Pouch the papillae are much larger in size and number compared to those prior.[9] The role and function of Tyler's Pouch is largely unknown.[9]

Adult characteristicsEdit

The threetooth puffer reaches a maximum length of 54 cm (21 in).[5] Its body is yellowish-brown with a white belly flap as large as or larger than its body which it inflates with seawater when threatened.[2] The flap is inflated by rotating the shaft-like pelvis downwards, exposing a black eye-spot contoured with yellow.[3][4][10] This makes the animal appear much larger to predators, and less likely to be eaten.[3] When danger is not present, the flap is retracted seamlessly into the body and the eye-spot is not visible.[2]

The head of an adult threetooth puffer makes up approximately 30.6% of the length of its body, and the eyes make up about 7.5% of its body length.[9] The upper jaw is composed of two dental plates while the teeth on the lower jaw protrude from a single dental plate, resulting in a beak.[2]

The threetooth puffer has ribs, a beak, and no pelvic fins which are all characteristics of tetraodontiformes.[7]

Adult scales have a rhombic base, and each has a median ridge from which several spines protrude.[9]

Juvenile characteristicsEdit

The smallest Triodon macropterus specimen on record measures 20mm long and belongs to the ichthyological section of the Muséum Nationale d'Histoire Naturelle in Paris.[9] The head of the specimen makes up 45% of the length of its body, and its eyes make up 18% of its body length.[9] As a juvenile, the pelvic bone is continuing to develop within the rotund belly.[9]

Juveniles have unicuspid scales, tricuspid scales, and pentacuspid scales.[9]

Danger to humansEdit

Triodon macropterus is harmless to humans unless eaten, at which point the species is considered poisonous.[2][4]

See alsoEdit


  1. ^ a b Matsuura, K. (2014): Taxonomy and systematics of tetraodontiform fishes: a review focusing primarily on progress in the period from 1980 to 2014. Ichthyological Research, 62 (1): 72-113.
  2. ^ a b c d e f g h Gomon, M.F. & Bray, D.J. (2011): Threetooth Puffer, Triodon macropterus, Fishes of Australia.
  3. ^ a b c Matsuura, K. & Tyler, J.C. (1998). Paxton, J.R. & Eschmeyer, W.N. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. p. 230. ISBN 0-12-547665-5.
  4. ^ a b c Binohlan, C.B. & Reyes, R.B. Triodon macropterus, Threetooth puffer in FishBase. March 2021 version.
  5. ^ a b Froese, Rainer; Pauly, Daniel (eds.) (2015). "Triodon macropterus" in FishBase. February 2015 version.
  6. ^ COPEPEDIA Molecular Info for Syntripsa Flavichela : T4015260 : Species, updated 11 Nov. 2020,
  7. ^ a b c Yamanoue, Y. et al. (19 July 2008). "A New Perspective on Phylogeny and Evolution of Tetraodontiform Fishes (Pisces: Acanthopterygii) Based on Whole Mitochondrial Genome Sequences: Basal Ecological Diversification?". BMC Evolutionary Biology. 8 – via BioMedCentral.
  8. ^ Froese, R. & Pauly, D. (December 2019). "Triodon macropterus Lesson, 1831". WoRMS - World Register of Marine Science. Retrieved March 12, 2021.
  9. ^ a b c d e f g h i j k Johnson, G.D., and Britz, R. (29 January 2005). "A Description of the Smallest Triodon on Record (Teleostei: Tetraodontiformes: Triodontidae)." Ichthyological Research, vol. 52, no. 2, pp. 176–181.
  10. ^ Bemis, Katherine E.; Tyler, James C.; Kaneko, Atsushi; Matsuura, Keiichi; Murakumo, Kiyomi; Espíndola, Vinicius C.; Justine, Jean-Lou; Tyler, Diane M.; Girard, Matthew G.; Bemis, William E. (2023-04-18). "Pelvic-Fan Flaring and Inflation in the Three-Tooth Puffer, Triodon macropterus (Tetraodontiformes: Triodontidae), with Additional Observations on Their Behavior in Captivity". Ichthyology & Herpetology. 111 (2). doi:10.1643/i2022022. ISSN 2766-1512.