| Southern stargazer | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Labriformes |
| Family: | Uranoscopidae |
| Genus: | Astroscopus |
| Species: | A. y-graecum |
| Binomial name | |
| Astroscopus y-graecum (Cuvier, 1829) | |
| Synonyms [2] | |
Uranoscopus y-graecumCuvier, 1829 | |
The southern stargazer (Astroscopus y-graecum) is a species of marine fish in the family Uranoscopidae and genus Astroscopus . They are native to the United States.
Southern stargazers are able to reach a maximum size of 440 millimetres (17 in). These fish have a brownish body color with small white spots, and their pectoral fins are lined in black and white. Their tails have three black or brown stripes on the caudal. They use their pectoral fins to dig and bury themselves in the sediment. [3] They have 8 dorsal spines, 13–14 soft dorsal rays, no anal spines, and 13 soft anal rays. They have a cleithral spine that has a venom gland. [4] When they bury themselves in the sand they leave their eyes, nostrils, and most of their mouth above the sand. In order to breathe they take water in through the nostrils which are protected from the sand by fleshy comb-shaped fringes; the mouth also has these fringes. These fish do not have scales on the top of their heads, but have them on the rest of their bodies extending onto the fleshy part of the caudal fin. Their eyes are able to protrude slightly from the head appearing stalked, and this is to allow them to see above the sand. [3] By using an organ located in a pouch behind their eyes they are able to create an electrical current. They are able to generate a voltage as strong as 50 volts, and this is mainly used for protection instead of a way to capture their prey. The discharge of this organ depends on the temperature of the water. [5]
A unique trait of the Southern Stargazer is its ability to use an electric organ. This adaptation is unique due to the fact that the Southern Stargazer is one of a few teleost that has this ability. This evolutionary ability is common with the genus Astroscopus, which includes the northern stargazer (A. guttatus) and the Brazilian stargazer (A. brasiliensis). [6] The organ itself is derived from muscles that are located around the eye. There are a total of eight muscles that comprise the organ; out of those eight, six are evolved from around the eye. [6] Some of the muscle groups that the organ is made up of are the medial rectus, the lateral rectus, the superior rectus, and the superior oblique muscle. [7] The cells that allow the muscle to produce an electric current are referred to as electro plaques. These cells are aligned on the surface of the Stargazer’s head in a vertical column, also referred to as the dorsal side. They extend from the dorsal fin on the back of the fish down on the head and then come to a stop near the mouth. These electro plaque cells are aligned in an irregular overlapping pattern. [6] This is different from other electrically conductive fish, such as the Torpedine. [8] The Torpedine is a ray that is found in the Atlantic Ocean as well. Instead of irregularly placed electro plaques, the Torpedine has overlapping, uniformly layered cells. This is important when considering the difference in electric conductivity between the two fish. The Torpedine is able to get up to a max voltage of 220 volts, while the Southern Stargazer can only go up to about 50 volts. [8] While Stargazers can conduct electricity, they are not the most effective at it. The cells that make up the organ are not very wide either; a single layer is about eight to ten cells wide. This width also fluctuates as it traverses the body, meaning variations in electrical current around the body. The widest section of the organ is typically found on the top side of the fish, and it is on average about 0.5 centimeters wide.
The Southern Stargazer has evolved to hunt effectively through the use of a highly specialized body form, specifically the shape of its head. The skull of a stargazer is flat and wide; this extends to the tip of its mouth, giving the fish a flat-like surface from the base of the skull to the very end of the mouth. [9] This adaptation is useful for hunting; while the fish buries itself into the sand, it can use its eyes and fins as lures. This allows the A. y-graecum to attract prey while being camouflaged safely under the sand. [10]
Another evolved adaptation is in the specialized positioning and shape of the stargazer's fins. The caudal, pectoral, anal, and pelvic fins have evolved to be strong enough to bury its body within the sand. The pelvic fins in particular have shifted towards the pectoral fins to aid in burying most of its head. Another adaptation is the positioning of the eyes. The stargazer's eyes sit on the dorsal side of its head, looking towards the surface of the ocean. They also have the ability to protrude their eyes away from their body a small distance to use as a lure or attractant for prey. This adaptation allows the fish to keep watch for prey while being buried in the sand. [9]
They are predatory fish that lie in wait for smaller fish to swim near them while they are buried under the sand with their head the only thing that is not buried. [3]
In a study conducted in 1979 by George H. Burgess from the University of North Carolina, he observed the unique feeding habits of A. y-graecum within an aquarium environment. [10] The stargazer, unable to bury into the sand due to the harsh substrate used to line the bottom of the aquarium, took to a different form of hunting prey. Swimming with its head at a 30-degree angle, emphasizing its black lateral stripe running along the lateral side of its body. Burgess observed that when the Stargazer was hungry, its body would turn a pale light yellow-gray. [10] He was able to identify this change in behavior because the Stargazer would begin stalking its prey only after it had changed color. Burgess also noted that the stargazer would attack fish that were of the same size as the stargazer and occasionally larger than its own size, never smaller. This was further reinforced by a previous study done in 1914, where they observed a similar feeding behavior. Another unique aspect of this type of hunting was that the stargazer always attacked its prey head-on. This is rather awkward for the stargazer, as its mouth and eyes do not point straight on but rather upwards towards the sky. This was demonstrated by the stargazer's many unsuccessful attempts at striking its victim. Burgess observed the fish often having to reposition itself and circling its prey. [10] Once the Stargazer was able to strike its victim, the prey gets swallowed into the stomach, in which the fish must greatly distend its abdomen. The prey within the stomach gets curled into a “u” shape, where it then continues to be digested. [10] This curling phenomenon was also observed in nature. Although, in nature, when the stargazer is able to get the prey into the stomach, it immediately tries to rebury itself into the sand to digest. [10] While the feeding behavior of the Southern Stargazer differs in an aquarium from in nature, different aspects, such as different ambush tactics and uses of electrical impulses, can still be further studied and explored, giving validity to the study.
The southern stargazers are benthic marine fish that are reef-associated. [4] They live most of their lives inshore. [3] Stargazers can be found at depths of 70 metres (230 ft) in areas that have sandy, silty, or soft rubble bottoms. [1]
Spawning occurs in the late spring and early summer months. They spawn on the bottom and their small transparent eggs slowly rise to the surface. When the eggs hatch the larvae are transparent that live in the water column. The larvae feed on their yolk sac until they reach a length of about 6–7 millimetres (0.24–0.28 in). Once they reach this size they start to feed off of other larvae in the water column. When they reach about 12–15 millimetres (0.47–0.59 in) in length their electric organs begin to form on the larvae, and they begin to head to the bottom and become a true juvenile. The juveniles are likely to move inshore to sandy bay, and may stay there for many years. This is where the juveniles develop the characteristics that the adults have. The eye will move to the top of the head, on the juvenile they are on the side of the head. Once they reach about 30 centimetres (12 in) in length they will move offshore and become adults. [3]
The southern stargazer is found in the western Atlantic from North Carolina, and south along the coast to the Gulf of Mexico to the Yucatán. [4] They can be found along the Caribbean Central and South America's coast from Mexico to Rio de Janeiro. [1] They are not found in the West Indies. [3]
Astroscopus is Latin for one who aims at the stars. [5]
The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins, composing the order Torpediniformes. They are known for being capable of producing an electric discharge, ranging from 8 to 220 volts, depending on species, used to stun prey and for defense. There are 69 species in four families.
Sand stargazers are blennioids; perciform marine fish of the family Dactyloscopidae. Found in temperate to tropical waters of North and South America; some may also inhabit brackish environments. The giant sand stargazer is the largest at 15 cm in length; all other species are under 10 cm.
The bluegill, sometimes referred to as "bream", "brim", "sunny", or, as is common in Texas, "copper nose", is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and wetlands east of the Rocky Mountains. It is the type species of the genus Lepomis, from the family Centrarchidae in the order Perciformes.
Astroscopus guttatus or the northern stargazer is a fish belonging to the Uranoscopidae family and was first described by Charles Conrad Abbott in 1860. Members of the Uranoscopidae family are characterized by dorsally or dorsolaterally directed eyes placed on or near the top of a large, flattened cuboid head, an oblique to vertical mouth often lined with cutaneous cirri, and an elongated, sub-compressed body. The Astroscopus genus consists of three species: Astroscopus guttatus, Astroscopus Y-graecum, and Astroscopus zepherus. Typically found on the Atlantic shores between the states of North Carolina and New York in the United States, the Northern Stargazer can sometimes be confused with its sister species the Southern Stargazer, Astroscopus y-graecum. Both A. guttatus and A. Y-graecum overlap in their distributions in Cape Hatterus One way to distinguish the Northern Stargazer from the Southern Stargazer is by the presence of numerous small white spots closely spaced along its head and back, whereas the Southern Stargazer has fewer, larger spots on its back. The Northern Stargazer is a moderately sized fish that can reach lengths of 22 inches (56 cm). The northern stargazer can be found buried in sandy substrate at depths up to 120 feet where the species remains buried awaiting prey. Stargazers have a flat forehead with a lot of body mass up front near the mouth creating a body plane optimal for remaining buried under sandy substrate.
The stargazers are a family, Uranoscopidae, of labriform ray-finned fish that have eyes on top of their heads. The family includes about 51 species in eight genera, all marine and found worldwide in shallow and deep saltwaters.
Barreleyes, also known as spook fish, are small deep-sea argentiniform fish comprising the family Opisthoproctidae found in tropical-to-temperate waters of the Atlantic, Pacific, and Indian Oceans.
Tetronarce californica also known as the Pacific electric ray is a species of electric ray in the family Torpedinidae, endemic to the coastal waters of the northeastern Pacific Ocean from Baja California to British Columbia. It generally inhabits sandy flats, rocky reefs, and kelp forests from the surface to a depth of 200 m (660 ft), but has also been known to make forays into the open ocean. Measuring up to 1.4 m (4.6 ft) long, this species has smooth-rimmed spiracles and a dark gray, slate, or brown dorsal coloration, sometimes with dark spots. Its body form is typical of the genus, with a rounded pectoral fin disc wider than long and a thick tail bearing two dorsal fins of unequal size and a well-developed caudal fin.
The starry flounder, also known as the grindstone, emery wheel and long-nosed flounder, is a common flatfish found around the margins of the North Pacific.
The horn shark is a species of bullhead shark, in the family Heterodontidae. It is endemic to the coastal waters off the western coast of North America, from California to the Gulf of California. Young sharks are segregated spatially from the adults, with the former preferring deeper sandy flats and the latter preferring shallower rocky reefs or algal beds. A small species typically measuring 1 m (3.3 ft) in length, the horn shark can be recognized by a short, blunt head with ridges over its eyes, two high dorsal fins with large spines, and a brown or gray coloration with many small dark spots.
In biology, the electric organ is an organ that an electric fish uses to create an electric field. Electric organs are derived from modified muscle or in some cases nerve tissue, called electrocytes, and have evolved at least six times among the elasmobranchs and teleosts. These fish use their electric discharges for navigation, communication, mating, defence, and in strongly electric fish also for the incapacitation of prey.
The marbled electric ray is a species of electric ray in the family Torpedinidae found in the coastal waters of the eastern Atlantic Ocean from the North Sea to South Africa. This benthic fish inhabits rocky reefs, seagrass beds, and sandy and muddy flats in shallow to moderately deep waters. It can survive in environments with very little dissolved oxygen, such as tidal pools. The marbled electric ray has a nearly circular pectoral fin disc and a muscular tail that bears two dorsal fins of nearly equal size and a large caudal fin. It can be identified by the long, finger-like projections on the rims of its spiracles, as well as by its dark brown mottled color pattern, though some individuals are plain-colored. Males and females typically reach 36–38 cm (14–15 in) and 55–61 cm (22–24 in) long respectively.
Samaridae is a family of crested flounders, small flatfishes native to the Indo-Pacific. The family contains four genera with a total of 29 species.
Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than 200 metres (660 ft) deep, it follows that pelagic coastal fish are generally epipelagic fish, inhabiting the sunlit epipelagic zone. Coastal fish can be contrasted with oceanic fish or offshore fish, which inhabit the deep seas beyond the continental shelves.
The Atlantic torpedo is a species of electric ray in the family Torpedinidae. It is found in the Atlantic Ocean, from Nova Scotia to Brazil in the west and from Scotland to West Africa and off southern Africa in the east, occurring at depths of up to 800 m (2,600 ft), and in the Mediterranean Sea. Younger individuals generally inhabit shallower, sandy or muddy habitats, whereas adults are more pelagic in nature and frequent open water. Up to 1.8 m (6 ft) long and weighing 90 kg (200 lb), the Atlantic torpedo is the largest known electric ray. Like other members of its genus, it has an almost circular pectoral fin disk with a nearly straight leading margin, and a robust tail with a large triangular caudal fin. Distinctive characteristics include its uniform dark color, smooth-rimmed spiracles, and two dorsal fins of unequal size.
The common dragonet is a species of dragonet which is widely distributed in the eastern North Atlantic where it is common near Europe from Norway and Iceland southwards. It is a demersal species that occurs over sand bottoms. It lives to a maximum age of around seven years. It is caught in bycatch by fisheries and is used in the aquarium trade.
Narcine brasiliensis, the Brazilian electric ray or lesser numbfish, is a species of electric ray in the family Narcinidae. It inhabits coastal waters of the Southwest Atlantic from Southern Brazil through Uruguay to northern Argentina.
The Atlantic stargazer is a marine, subtropical fish of family Uranoscopidae. Its body is suited for living on the sea floor, and is one of few fish capable of bioelectrogenesis, or the ability to generate an electric charge.
The Atlantic mudskipper is a species of mudskipper native to fresh, marine, and brackish waters of the tropical Atlantic coasts of Africa, including most offshore islands. The Greek scientific name Periophthalmus barbarus is named after the eyes that provide the Atlantic mudskipper with a wide field of vision. The Atlantic mudskipper is a member of the genus Periophthalmus, which includes oxudercine gobies that have one row of canine-like teeth.
Astroscopus, the electric stargazers, is a genus of stargazers, a type of percomorph fish from the family Uranoscopidae, part of the order Labriformes. The species in this genus are anatomically distinct uranoscopids, being characterized by internal nares and being the only group of marine bony fish having organs which produce electricity which are derived from the extraocular muscles. They are found on the Atlantic and Pacific coasts of the Americas.
Urocampus nanus, commonly known as the barbed pipefish, is a species of marine fish belonging to the family Syngnathidae. This family consists of 56 different genera and 320 species.
[3] [4] [5] [11] [8] [12] [10] [9] [7] [6]
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