Photophore

A photophore is a glandular organ that appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors.[1] The bioluminescence can variously be produced from compounds during the digestion of prey, from specialized mitochondrial cells in the organism, called photocytes ("light producing" cells), or, similarly, associated with symbiotic bacteria in the organism that is cultured.

The character of photophores is important in the identification of deep sea fishes. Photophores on fish are used for attracting food or for camouflage from predators by counter-illumination.

Photophores are found on some cephalopods, including firefly squid, the sparkling enope or firefly squid, which can create impressive light displays.[1]

Lycoteuthis "diadema"

Arrangement of various photophores on the squid Lycoteuthis lorigera

Hygophum hygomii Photophores

Photophores on a lanternfish, the most common deep sea fish worldwide

Gigantactis

This anglerfish has a dorsal fin whose first ray has become very long and is tipped with a luminous photophore fishing lure

Histioteuthis reversa (Michael Vecchione, NOAA)
The elongate jewel squid (Histioteuthis reversa), so called because the photophores festooning its body make it appear bejewelled
Cephalopod photophore structu
Diagram of a cephalopod's photophore, in vertical section

See also

References

  1. ^ a b "Cephalopod Photophore Terminology". Tolweb.org. Retrieved 2012-08-30.
Australiteuthis

Australiteuthis aldrichi is a small species of squid from northern Australian waters. It was described by Chung Cheng Lu in 2005 based on specimens collected in inshore waters of Northern Australia. The largest known individual of this species is a mature female measuring 27.6 mm in mantle length (ML). The holotype is a mature male of 21.3 mm ML. A. aldrichi has never been seen alive. It is the only member of the genus Australiteuthis and the family Australiteuthidae.

A. aldrichi is characterised by several unique morphological features. It has an unusual funnel locking apparatus which contains a boomerang-shaped groove. Its fins are separated from each other and possess posterior lobes. The ink sac contains a dumbbell-shaped photophore.

The species is named after Frederick Allen Aldrich (1927–1991), a prominent teuthologist and former Moses Harvey Professor of Marine Biology at Memorial University of Newfoundland.

Bolitaeninae

The Bolitaeninae are a subfamily, in the family Amphitretidae, of small, common pelagic octopuses found in all tropical and temperate oceans of the world. The taxonomy of this taxon is not entirely certain; recent research suggests just two genera exist, Bolitaena and Japetella, both of which are thought to be monotypic by some authorities and under this view, the family would represent two very similar species: Bolitaena pygmaea and Japetella diaphana. However, currently a second species of Bolitaena, B. massyae is also recognised.

Choneteuthis tongaensis

Choneteuthis tongaensis is a species of bobtail squid native to the waters around the Tonga Islands in the southern Pacific Ocean. It is known from only three specimens. Of these, the holotype is the largest, at 33.8 mm mantle length (ML). C. tongaensis is characterised by several distinct morphological features: the mantle is free from the head in the nuchal region, a large, circular visceral photophore and ventral shield are present on the ventral surface of the ink sac, and the broad keel extends the full length of the club.The holotype (MNHN 3820), a female with missing tentacles, was collected in the N Ha’apai group of the Tonga Islands (19°42′S 174°26′W) at a depth of 332 m. Paratype 1, a male known from only the head and brachial crown, came from the same station. Paratype 2 (MNHN 3822), also a female with missing tentacles, was collected from a seamount in the Tonga Islands (22°11′S 175°27′W) at a depth of 385–405 m.

Chtenopteryx sicula

Chtenopteryx sicula, also known as the comb-finned squid or toothed-fin squid, is a species of squid native to at least the Mediterranean Sea. It is characterised by several distinct morphological features: ocular photophores are present but visceral photophores are absent, arm suckers are arranged in at least 4 series distally, and club suckers are borne in more than 8 series.

The type specimen was collected off Messina, Italy; the specific name sicula means "of Sicily". It is deposited at the Muséum d'Histoire Naturelle (Musée Barla) in Nice.

Echinoteuthis atlantica

Echinoteuthis atlantica is a species of whip-lash squid from the family Mastigoteuthidae. It occurs in the eastern North and South Atlantic Ocean. This squid is red in colour and similar to Echinoteuthis famelica of the Pacific but differs in having a well developed protective membrane on the tentacular club which is absent on E. famelica. The presence on this membrane on Echinoteuthis glaukopis from the Indian Ocean suggests that this may be a synonym of E. atlantica, in which case glaukopis has priority.

Flashlight (disambiguation)

A flashlight is a portable self-contained electric spotlight, also known as a torch.

Flashlight or flash light or Flash Light may also refer to:

Flash (photography), or the flashlight, a device used for instantaneous illumination during picture taking

Flashlight fish (disambiguation), a common name for several fishes

The photophore, beside the eye of certain fish

Yakovlev Yak-25, a Soviet military jet which NATO designates as "Flashlight"

Yakovlev Yak-27, NATO designation "Flashlight-C"

The Flashlight, a 1917 silent film starring Lon Chaney, Sr.

Gadella

Gadella is a genus of morid cod. The species in this genus are characterised by the absence of a chin barbell, an anterior dorsal fin with 7-11 rays, a long based anal fin which has a straight profile, the outermost rays of the pelvic fin are filamentous and extend a small distance beyond the membrane. They do not have a photophore. The Gadella codlings are found around the tropical and subtropical seas around the world on the outer continental shelf to the mid continental slope. They are of no interest to fisheries.

Gigantactis

Gigantactis is a genus of deep-sea fish of the family Gigantactinidae. The species in this genus are poorly known and found in all oceans, at depths of 1,000–2,500 metres (3,300–8,200 ft). The most striking feature of these fish is extremely enlarged first filament of dorsal fin, called the illicium, with bioluminescent photophore at its end.

Macrouridae

Macroudidae is a family of deep sea fish, a diverse and ecologically important group, which are part of the order of cod-like fish, the Gadiformes. The species in the Macrouridae are characterised by their large heads which normally have a single barbel on the chin, projecting snouts, and slender bodies that taper to whip-like tails, without an obvious caudal fin but what there is of the caudal fin is often confluent with the posterior dorsal and anal fins. There are normally two dorsal fins, the anterior dorsal fin is quite high, the posterior quite low but is longer and takes up a greater proportion of the fish's of the back, species in the subfamily Macrouroidinae have a single dorsal fin. The long anal fin is almost as long as the second dorsal fin is nearly as long as the posterior dorsal, and sometimes it is longer. The pelvic fin is inserted in the vicinity of the thorax and normally has 5-17 fin rays but are absent in Macrouroides. The body is covered in small scales and if they have a photophore, it is usually on the midline of the abdomen just in front of the anus. The bioluminescence of these fish is produced by symbiotic bioluminescent bacteria. The structure of the skull has been used to show their placing in the Gadiformes, but they differ from the typical cods in that they possess one stout spine in the anterior dorsal fin.The species in this family are mainly benthopelagic, they are found at depths of 200-2000 m, they occur on the sea bed and have a wide distribution from the Arctic to the Antarctic. The species in the Macrouridae normally live near the sea bed on the continental slope, however, some species are bathypelagic or mesopelagic, other species occur on the outer continental shelf. Their bodies are loose in texture rather than firm and they are weak swimmers. Some species are of commercial importance to fisheries.

Malacosteus australis

The Southern stoplight loosejaw, Malacosteus australis, is a species of barbeled dragonfish. This species is mainly distinguished from M. niger by a smaller postorbital photophore in both sexes and lower numbers of lateral photophores. It also differs in having somewhat smaller jaws, a fleshy orbit, and several subtle morphological traits. The maximum known length is 16.6 cm (6.5 in) for a male and 19.2 cm (7.6 in) for a female. Its specific epithet comes from the Latin austral, meaning "southern".

Malacosteus niger

Malacosteus niger is a species of fish in the family Stomiidae, the barbeled dragonfishes. It is known by the common names northern stoplight loosejaw, lightless loosejaw, black loosejaw, and black hinged-head. It lives in oceans around the world from tropical to subarctic waters.

The postorbital photophore in this species is larger than in M. australis. It also differs in lateral photophore count, as well as in morphological characters. The maximum known length is 25.6 cm (10.1 in). Its specific epithet niger is Latin for "black".M. niger occurs in the mesopelagic zone of all oceans. Contrary to barbeled dragonfishes in general, it is not a vertical migrator. While the morphology of M. niger with huge fangs and an enormous gape is typical for its family and suggests adaptations to piscivory, its diet in fact contains a substantial proportion of zooplankton. It is suggested that its dominant feeding mode is searching for zooplanktonic prey (copepods in particular) using bioluminescence to illuminate a small search area, with infrequent encounters with larger prey items. The likely origin of the pigment necessary for detecting its long wavelength bioluminescence, a chlorophyll derivative, is the copepods themselves.

Mastigotragus

Mastigotragus is a genus of whip-lash squid containing a single species, Masigotragus pyrodes. This species was originally placed within Mastigoteuthis, but has been subsequently separated from other species in that genus due to multiple morphological characters. This genus is characterized by a lack of antitragus in the funnel-locking cartilage, larger sucker rings on the tentacles, a particular photophore morphology, and relatively large eyelid photophore. This genus is Latin for 'whip-lash goat'.

The type specimen was collected in the North pacific off the coast of southern California at 33°32'N, 118°23'W Eastern North Pacific since then the species has been recorded in northern Hawaiian waters between latitudes 23°N-28°N.

Nematolampas regalis

Nematolampas regalis, the regal firefly squid is a small, little known species of squid from the family Lycoteuthidae which is found in the subtropical South Pacific Ocean. This squid has a mantle length of 30mm. It may be sexually dimorphic with the males possibly having very thin elongated arms III which are increasingly thread like towards their tips where they do not have any suckers. Arms II are "normal" and have suckers along their length. The third arms have a series of photophores along their length and there is a small photophore located on each of the tips of arms I and II. The tentacles have two embedded photophores and the largest of the eye's photophores is in the centre. There is a pair of large photophores vlose to the tip of the mantle on the ventral side mantle; with no other photphores on the body except for a visceral photophore which is also near the tip. There is practically no tail. N. regalis is known only from the Kermadec Islands near New Zealand, one of the specimens was beached while the other two were caught by a trawl at a depth of 48m.

Photocyte

A photocyte is a cell that specializes in catalyzing enzymes to produce light (bioluminescence). Photocytes typically occur in select layers of epithelial tissue, functioning singly or in a group, or as part of a larger apparatus (a photophore). They contain special structures termed as photocyte granules. These specialized cells are found in a range of multicellular animals including ctenophora, coelenterates (cnidaria), annelids, arthropoda (including insects) and fishes. Although some fungi are bioluminescent, they do not have such specialized cells.

Photophore (disambiguation)

Photophores are light-emitting organs found in various marine animals.

Photophore may also refer to:

An instrument (a type of endoscope) used to observe internal organs and tissues

A wax candle holder used in home decoration that creates ambiance once lit

Pterygioteuthis

Pterygioteuthis is a genus of squid in the family Pyroteuthidae. Members are differentiated from the genus Pyroteuthis due to size and head shape. The genus is characterised by the presence of a lidded photophore over each eye.

Pyroteuthis margaritifera

Pyroteuthis margaritifera, the jewel enope squid, is a species of squid in the family Pyroteuthidae.

This species has three large, ellipsoidal, double photophores on the tentacles, the nearest ellipsoidal photophore to the tip is near the carpal cluster and is widely separated from the two smaller spherical photophores at the base of the tentacle, but nearer to the other two ellipsoidal photophores. Another spherical photophore is located at the base of the tentacular club. The fourth right arm is hectocotylised and has 13-19 basal hooks, each of these hooks is large and has a primary cusp with a smooth inner edge and a large, rounded secondary cusp. Betong these basal hooks there is a fleshy, elongated pad, this is a flap in other species of Pyroteuthis, with three hooks opposite it and between zero and thirteen suckers at its tip.P. margaritifera has been collected off Bermuda from depths of 375-500 m in the day and between 75 and 175 m during the night. It is a widely distributed species which occurs throughout the tropical and temperate Atlantic, Indian and South Pacific Oceans but has not been recorded from the eastern Pacific. It was originally described by the German naturalist Eduard Rüppell in 1844 as Enoploteuthis margaritifera from specimens taken in the Mediterranean. It shows some geographic variation.

Stoplight loosejaw

The stoplight loosejaws are small, deep-sea dragonfishes of the genus Malacosteus, classified either within the subfamily Malacosteinae of the family Stomiidae, or in the separate family Malacosteidae. They are found worldwide, outside of the Arctic and Subantarctic, in the mesopelagic zone below a depth of 500 meters (1,600 feet). This genus once contained three nominal species: M. niger (the type), M. choristodactylus, and M. danae, with the validity of the latter two species being challenged by different authors at various times. In 2007, Kenaley examined over 450 stoplight loosejaw specimens and revised the genus to contain two species, M. niger and the new M. australis.Malacosteus and the related genera Aristostomias, Chirostomias and Pachystomias are the only fishes that produce red bioluminescence. As most of their prey organisms are not capable of perceiving light at those wavelengths, this allows Malacosteus to hunt with an essentially invisible beam of light. Furthermore, Malacosteus is unique amongst animals in using a chlorophyll derivative to perceive red light. The name Malacosteus is derived from the Greek malakos meaning "soft" and osteon meaning "bone". Another common name for these fishes is "rat-trap fish", from the unusual open structure of their jaws.

Viperfish

The name "viperfish" is also sometimes applied to the lesser weever.

A viperfish is any species of marine fish in the genus Chauliodus. Viperfish are characterized by long, needle-like teeth and hinged lower jaws. A typical viperfish grows to lengths of 30 to 60 cm (12 to 23.5 in). Viperfish stay near lower depths (250–5,000 feet [80–1,520 m]) in the daytime and shallower depths at night, primarily in tropical and temperate waters. Viperfish are believed to attack prey after luring them within range with light-producing organs called photophores, which are located along the ventral sides of its body, and with a prominent photophore at the end of a long spine in the dorsal fin reminiscent of the illicium of the unrelated deepsea anglerfishes. The viperfish flashes this natural light on and off, at the same time moving its dorsal spine around like a fishing rod and hanging completely still in the water. It also uses the light producing organ to communicate to potential mates and rivals.

Viperfish vary in color from green, silver, to black. A viperfish uses its fang-like teeth to immobilize prey and would not be able to close its mouth because of their length, if it were not able to fold and curve them behind its head. The first vertebra behind the head of the viperfish absorbs the shock of biting prey. As with other deepsea fish, they are able to undergo long periods with scarcely any food.

Viperfish are believed to live from 30 to 40 years in the wild, but in captivity they rarely live more than a few hours. Some species of dolphins and sharks are known to prey upon viperfish. Scientists believe they can swim at a speed of two body lengths per second, but this is not yet an official speed.

Although it may look like it is covered in scales, it in fact is covered by a thick, transparent coating of unknown substance. Extremely large, fang-like teeth give the fish a slightly protruded lower jaw which makes catching prey easy for this deep-sea predator. The viperfish is lined with three different types of photophores which some speculate is used to lure in unsuspecting prey They have microscopic spheres without a pigment layer that are scattered over the dorsal side, large spheres with a pigment coat, reflectors, and lens, and finally, large, bell-shaped organs with a pigment coat, reflectors, and lens that are grouped together in rows along the dorsal surface. Photophores can also be seen along the ventral and lateral surface of the fish.

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