The spot-fin porcupinefish (''Diodon hystrix''), also known as the spotted porcupinefish, black-spotted porcupinefish or simply porcupinefish, is a member of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Diodontidae.

Description

The spot-fin porcupinefish is a medium-sized fish which grows up to 91 cm, but the average size mostly observed is 40 cm. Its body is elongated with a spherical head with big round protruding eyes, and a large mouth which is rarely closed. The

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s are large, the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s are absent, and the anal and

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

s are close to the caudal peduncle. The latter move simultaneously during swimming. The skin is smooth and firm; the scales are modified into spines. The body coloration is beige to sandy-yellow marbled with dark blotches and dotted with numerous small black spots. In case of danger, the porcupinefish can inflate itself by swallowing water to deter the potential predator with its larger volume and it can raise its spines. The porcupinefish concentrates

tetrodotoxin Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered ...

in certain parts of its body such as the

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

s and the

viscera In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a ...

. This defensive system constitutes an additional device to dissuade potential predators.

Distribution and habitat

The porcupinefish is circumglobal, found in

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

waters. It has been recorded twice in the Mediterranean Sea, off southern Italy (1963) and the Balearic islands (2016).Atlas of Exotic Fishes in the Mediterranean Sea (Diodon hystrix). 2nd Edition. 2021. 366p. CIESM Publishers, Paris, Monaco.https://ciesm.org/atlas/fishes_2nd_edition/Diodon_hystrix.pdf Juveniles are

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

up to the time that they are about 20 cm in length. Adults favour

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') a ...

s, top reefs and seaward coral or rocky

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock out ...

s from one to 50 m depth, sheltering under ledges or in caves during the day.

Feeding

The porcupinefish's diet is based on

sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

s, clams and

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s.Leis, J.M., 2001. Diodontidae. Porcupine fishes (burrfishes). p. 3958-3965. In K.E. Carpenter and V. Niem (eds.) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Vol. 6. Bony fishes part 4 (Labridae to Latimeriidae), estuarine crocodiles. FAO, Rome.

Behavior

This fish is solitary, except during mating periods, and it has a

nocturnal activity ''Nocturnal Activity'' is a remix album by Rae & Christian, released in 2002 on the independent record label Grand Central Records. It is composed of alternative mixes of the tracks from Sleepwalking (Rae & Christian album), ''Sleepwalking'' albu ...

with a maximal activity at sunset and sunrise.

Parasites

Parasite140092-fig2 FIG 6 Cestoda Trypanorhyncha Molicola horridus in Diodon hystrix liver

As with most fish, the porcupinefish is infected by a variety of

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s. Spectacular parasites are the cysts of the larvae of the trypanorhynch cestode '' Molicola horridus'', often found in great numbers in the liver. These parasites represent no danger to humans.

References

External links

*http://vintage-royalty-free-images.com/porcupine-fish-diodon-hystrix-p-505.html *http://www.marinespecies.org/aphia.php?p=taxdetails&id=127403 *http://www.fishbase.org/summary/1022 *http://eol.org/pages/1012692/details *http://doris.ffessm.fr/fiche2.asp?fiche_numero=2379 * {{Taxonbar, from=Q1328265 spot-fin porcupinefish Pantropical fish spot-fin porcupinefish spot-fin porcupinefish