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43-564: Orestias humboldti Valenciennes, 1846 The Titicaca orestias , Lake Titicaca orestias , or Lake Titicaca flat-headed fish ( Orestias cuvieri ), also known by its native name amanto , is a likely extinct freshwater killifish from Lake Titicaca in South America. It belongs in the pupfish genus Orestias , endemic to lakes, rivers and streams in the Andean highlands. With a total length of up to 27 cm (10.6 in), it

86-499: A band on the lateral line and as small groups on the upper lateral sides. Small melanophores cover the fins giving them a grayish color. The grayish color fades to white on the dorsum and belly; juvenile pigmentation pattern persists with little modification in adult males and females. This information shows that the color of the Orestias in question depends on what part of the body is being considered. Nothing has been published about

129-443: A female has the potential to spawn at least five times during her life. In each spawning a female can typically lay more than 10,000 eggs, but the full range reported in the species is from 1,170 to 30,300 eggs, with large and old females producing more than smaller and younger. The eggs are laid in shallow water in clusters attached to submerged macrophytes . The eggs hatch into fish larvae after around 13–14 days. The growth of

172-453: A result of overfishing, predation by introduced species, and the impacts of intensive production in trout farms. This idea of law enforcement is particularly challenging because of the immense body of water that would need patrolling. Actions to be on the lookout for by law enforcement should include long casting; where a long line (over 100 kilometers in some instances) is cast and other unintended fish are caught. Perhaps more importantly though

215-536: A smaller number also spawn from August to November (occasionally December) when the water temperatures typically is between 13 and 21 °C (55–70 °F). Even short periods where the water is more than 23 °C (73 °F) during the spawning season can prevent the adults from breeding. Some females that spawn in August–September may spawn a second time in the same season in October–December. In theory,

258-477: Is a species of Neotropical silverside , an euryhaline fish native to fresh, brackish and salt water in south-central and southeastern South America, but also introduced elsewhere. It is often known by the common name Argentinian silverside or pejerrey (the latter is of Spanish origin, meaning "king fish," the Latin piscis given rise to "pez," fish , and "peje," a kind of fish, and "rey," king ), but it

301-674: Is considered an excellent food fish , and it is of major economic importance in both its native range and where introduced. Many thousand tonnes are caught each year. It is also considered a good game fish . It is sometimes kept in aquaculture due to its ability to live in a wide range of environments, the ease of breeding it in captivity and its fast growth. In Lake Titicaca where introduced they are typically caught when around 20 cm (8 in) long and 100 g (3.5 oz) in weight, but those caught in its native Argentina typically are around 27 cm (11 in) long and weigh 300 g (11 oz). However, some populations, notably

344-656: Is inadequate, bigger fish will eat the smaller fish. Some strains have a lifespan as short as several months and can thus serve as a model for biogerontological studies. The African turquoise killifish ( Nothobranchius furzeri ) is the shortest-living vertebrate that can be bred in captivity, having a lifespan of between three and nine months. Sexual maturation occurs within 3–4 weeks, with fecundity peaking in 8–10 weeks. Nothobranchius furzeri shows no signs of telomere shortening, reduced telomerase activity, or replicative senescence with age, despite its short lifespan. Nonetheless, lipofuscin accumulates in

387-824: Is native to subtropical and temperate South America east of the Andes where it ranges from around the Río Negro basin in Argentina, north throughout most of the northern half of that country, to the Río de la Plata Basin in south Brazil, Paraguay and Uruguay . In coastal Atlantic parts of South America it ranges at least from the southernmost Buenos Aires Province in Argentina to Rio Grande do Sul State ( Lagoa dos Patos ) in Brazil. It has been introduced to many places outside its native range, including Argentina (in parts of

430-608: Is not the only species of silverside in Uruguay and Argentina and pejerrey is also used for many other silversides. It is a commercially important species and the target of major fisheries. O. bonariensis resembles the other species in the genus Odontesthes , but it is larger, generally reaching up to 50 cm (1.6 ft) in total length, and exceptionally as much as 82 cm (2.7 ft) long and 5.2 kg (11 lb 7 oz) in weight (reports of even larger are unconfirmed and questionable). Odontesthes bonariensis

473-722: Is of uncertain origin, but is likely to have come from the Dutch kil for a kill (small stream). Although killifish is sometimes used as an English equivalent to the taxonomical term Cyprinodontidae, some species belonging to that family have their own common names, such as the pupfish and the mummichog . Killifish are found mainly in fresh or brackish waters in the Americas, as far south as Argentina and as far north as southern Ontario and even Newfoundland and Labrador . There are also species in southern Europe , in much of Africa as far south as KwaZulu-Natal , South Africa , in

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516-591: Is particularly common in Pampas lakes that generally are less than 4 m (13 ft) deep. The species is able to live in fresh, brackish and salt water ( salinity up to 3.5%), but not in hypersaline conditions. The water temperature can range at least from 7 to 30 °C (45–86 °F); in short periods they can even survive in waters where the surface has frozen. Temperatures of 32 °C (90 °F) are lethal to most individuals, and when above 25 °C (77 °F) they often perish due to increases of

559-502: Is quite fast: They are typically around 14 cm (5.5 in) long when one year old, 24 cm (9.5 in) when two, 35 cm (14 in) when three, 43 cm (17 in) when four and 50 cm (20 in) when five years. They first reach maturity when 1–2 years old. Males are mature from a length of about 10.5 cm (4.1 in) and females from about 19.5 cm (7.7 in). Most females spawn in March and April, but

602-518: Is specifically adapted to the unique basin in which it lives and any alteration to the dynamics of the body of water would greatly impact the fish. Human introduction of foreign fishes to the Altiplano basins predictably had negative consequences. The alien species created competition and preyed upon Orestias cuvieri , eventually leading to its extinction. Pollutants contaminate the water and traces of metals, such as zinc and copper, have been found in

645-816: Is to be on the lookout, as an entity of law enforcement for pollution. The National Museum of Natural History in the Netherlands, Naturalis , has several specimens . Two of these specimens were donated by the Zoological Museum at Heidelberg University in 1877 and one in 1880 from the Smithsonian Institution . In addition, four specimens, labeled " Orestias humboldti " were donated by the Muséum national d'histoire naturelle in France. Scientists have determined that there are 44 species of

688-436: The genetic diversity of the species have enabled it to evolve and survive in areas where other species have died out, including Superfund sites . Over a few dozen generations of killifish in a relatively short period of time (50–60 years), killifish have evolved resistance against levels of dioxins , PCBs, mercury, and other industrial chemicals up to 8,000 times higher than the previously estimated lethal dose. Sequencing

731-437: The parasitic Lernaea copepods (also a primary reason for failed introduction attempts of O. bonariensis in some countries), the bacteria Aeromonas hydrophila and algal blooms . Overall the species is widespread and common, but global warming can increase the temperature and salinity in some placed inhabited by O. bonariensis , representing a threat to these local populations. The growth rate of O. bonariensis

774-459: The African genus Nothobranchius and South American genera ranging from the cold water Austrolebias of Argentina and Uruguay to the more tropical Gnatholebias , Pterolebias , Simpsonichthys and Terranatos . A small number of species will shoal while most are territorial to varying degrees. Populations can be dense and territories can shift quickly, especially for species of

817-621: The Middle East and Asia (as far east as Vietnam ), and on several Indian Ocean islands. The majority of killifish are found in permanent streams, rivers, and lakes, and live between two and three years. Such killifish are common in the Americas ( Cyprinodon , Fundulus and Rivulus ) as well as in Africa and Asia (including Aphyosemion , Aplocheilus , Epiplatys , Fundulopanchax and Lacustricola ) and southern Europe ( Aphanius ). Some of these habitats can be rather extreme;

860-540: The adult O. cuvieri were granulated. The concave dish shape of its body and jaw further helped distinguish O. cuvieri from other species of Orestias . The anatomy of O. cuvieri closely resembled a species of trout which is now found in Lake Titicaca, a similarity which has led many researchers to hypothesize that competition between the two groups was the reason for the extinction of O. cuvieri . Each species of Orestias has varying size. The Titicaca orestias

903-488: The brain and liver (associated with age-related neurodegeneration ), and there is an increased risk of cancer with age. Calorie restriction reduces these age-related disease conditions. Resveratrol has been shown to increase the mean (56%) and maximum life span (59%) of Nothobranchius furzeri , but resveratrol has not been shown to have this effect in mammals. Transferring the gut microbiota from young killifish into middle-aged killifish significantly extends

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946-467: The country where not native), Bolivia, Brazil (in parts of the country where not native), Chile, Peru, Morocco (where probably not established), Italy (only Lake Nemi ), Israel (failed to become established) and Japan. O. bonariensis is highly adaptable and can live in a wide range of habitats. This includes both stagnant and flowing waters, such as rivers, streams, channels, lakes, reservoirs, estuaries and coastal lagoons. In much of its range it

989-479: The embryo sac. The freshwater fish belonging to the genus Orestias are found in high-altitude isolated lakes in the Altiplano region of South America, ranging from Peru to Chile. Lake Titicaca , which is on the border of Peru and Bolivia, contains a wide variety of Orestias fish. This large lake was once the home to Orestias cuvieri before their extinction. At one time, there were as many as 30 native fish species in Lake Titicaca, of which 28 species belonged to

1032-980: The extreme shallows (a few centimetres of water). Many species exist as passive tribes in small streams where dominant males will defend a territory while allowing females and immature males to pass through the area. In the aquarium, territorial behaviour is different for every grouping, and will even vary by individuals. In a large enough aquarium, most species can live in groups as long as there are more than three males. Killifish feed primarily on aquatic arthropods such as insect ( mosquito ) larvae , aquatic crustaceans and worms. Some species of Orestias from Lake Titicaca are planktonic filter feeders . Others, such as Cynolebias and Megalebias species and Nothobranchius ocellatus are predatory and feed mainly on other fish. The American Flagfish ( Jordanella floridae ) feeds heavily on algae and other plant matter as well as aquatic invertebrates. Nothobranchius furzeri needs much food because it grows quickly, so when food supplied

1075-479: The genomes of the adapted individuals showed a common set of mutations among the pollution-tolerant fish, many of which help to deactivate or turn off a molecular pathway responsible for a large part of the cellular damage caused by the chemicals. Killifish were found to fare relatively well in the wake of the Deepwater Horizon oil spill . Odontesthes bonariensis Odontesthes bonariensis

1118-404: The genus Orestias . Other related species of Orestias live in the region, forming a species flock . The Titicaca orestias was characterized by a unique pattern of pores on the head. Large thick scales lined the median dorsal ridge and thinner smaller scales surrounded the ridge. Between these two areas of skin were patches with no scales. Unlike most other species of Orestias , the scales of

1161-462: The genus Orestias . In the middle of the 20th century, there were many attempts to introduce exotic species to the lake. Two of these introductions were successful: rainbow trout introduced in 1942 and silverside ( Odontesthes bonariensis ) in the early 1950s. The success of the silverside meant the decline of the Titicaca orestias, since the larger silversides were observed to eat them. As long as

1204-479: The genus Orestias . These species were divided into four groups by the American ichthyologist Lynne R. Parenti in 1984. In 2003, Arne Lüssen researched the phylogeny , including the mtDNA sequence data of many species. The Lake Titicaca orestias, O. cuvieri , is a member of the cuvieri species complex , which also includes O. forgeti , O. ispi and O. pentlandii . Killifish The word killifish

1247-690: The juvenile stage. Hybridization with other species in the genus Odontesthes has occurred both in captivity and the wild. In the first part of their life O. bonariensis mostly feed on zooplankton . When reaching around 10 cm (4 in) long they start to mainly feed on insects; both aquatic insect larvae and land insects that fall into the water. From an age of around 4 years they become more piscivorous , even cannibalising young of their own species. Other food items recorded in lower quantities are shrimp, snails and plants ( algae and seeds). In captivity they will eat commercially available dry pellets developed for feeding trout . This species

1290-631: The larvae is negligible at temperatures of 15 °C (59 °F) or less, and they die at 29 °C (84 °F). As known from some other Neotropical silversides, the temperature determines the sex in O. bonariensis . When the larvae and juveniles grow up in water that is 19 °C (66 °F) or colder, all become females. At higher temperatures the percentage of males gradually increases, and at 23 °C (73 °F) or warmer most become males. The larvae are unable to survive salinities of 3% (they thrive from 2% to pure fresh water), but they can already live at this relatively high range once they reach

1333-529: The lifespans of the middle-aged killifish. Transgenic strains have been made, and precise genome editing was achieved in Nothobranchius furzeri using a draft genome and the CRISPR/Cas9 system. By targeting multiple genes, including telomerase , the killifish can now be used as an attractive vertebrate model organism for aging and diseases (such as Dyskeratosis congenita ). Sequencing

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1376-544: The mouth of the Striped panchax is as wide as the head, and much smaller fish will be eaten. Flagfish , native to south Florida, is another species of killifish commonly found in pet stores. They are useful in aquariums for algae control. The golden topminnow ( Fundulus chrysotus ) is also native to the United States and often available at auction, but care must be taken with these fish to stop them from jumping out of

1419-712: The one in Lake Titicaca, contain levels of metals from pollution that exceed the internationally recommended safety thresholds for human consumption. Although it has significantly aided the local economy in many places where introduced, it has become invasive in some places, causing serious problems to the native species. It is one of the causes of the major declines in Orestias pupfish and Trichomycterus catfish in Bolivia, Peru (notably Lake Titicaca where O. cuvieri has become extinct and relatives declined) and Chile. Another vulnerable habitat where it has been introduced

1462-563: The only natural habitat of the Devils Hole pupfish ( Cyprinodon diabolis ) is Devils Hole : a cavern at least 91 metres (299 ft) deep, branching out from a small opening at the surface, approximately 1.8 metres (6 ft) by 5.5 metres (18 ft) wide. Some specialized forms live in temporary ponds and flood plains, and typically have a much shorter lifespan. Such species, known as "annuals", live no longer than nine months, and are used as models for studies on aging. Examples include

1505-439: The reproduction of the Titicaca orestias, but in other Orestias species of Lake Titicaca, the males become more orange or yellow in color when they are spawning. During their reproductive stage, the females lay somewhere between 50 and 400 eggs, each of which has a yellowish filament up to about 2.5 mm in diameter. As an adaptation to solar radiation, the eggs develop a black protective coat, derived from melanophores , around

1548-613: The silverside continued to flourish, it meant difficult times for the amanto. Fifty years ago, there was no sign of Orestias cuvieri in Lake Titicaca and the species was presumed to be extinct. O. cuvieri mainly ate smaller fish. Since the Miocene era , species of Orestias have lived in relative isolation. Most of the aquatic regions in the Altiplano region are endorheic , meaning that they are closed off from drainage and do not let any water out. Thus, species of Orestias have been confined to their respective basins. Each group of fish

1591-548: The species O. cuvieri . Thus, the extinction of the Titicaca orestias is largely anthropogenic . With regard to law enforcement, major efforts are still needed to prevent pollution and illegal fishing. These efforts need to be made specifically on the area, between Peru and Bolivia, of Lake Titicaca . O cuvieri has likely already become extinct. Other native species, including the suche ( Trichomycterus rivulatus ), boga ( O. pentlandii ), yellow karachi ( O. albus ) and ispi ( O. ispi ), are threatened to various degrees, as

1634-443: The tank. A firm cover and a layer of floating plants is best when keeping these fish. Normally, killifish avoid near-surface water to reduce the danger of being eaten by predators. However, when infected with a type of fluke the fish swim near the surface, and sometimes even swim upside down, exposing their camouflaged bellies. The fluke completes its lifecycle in the digestive tract of birds. The large populations of killifish and

1677-443: The tissues of fishes. In addition, runoff from fertilizers and pesticides used in agricultural lands has been extremely toxic to the fish. The water from the Altiplano region is also in high demand. People have constantly been taking water out of the basins and depleting the Orestias habitats. The compilation of the effects of human actions have harmfully affected the health and survival of different species of Orestias , in particular

1720-526: The whole killifish genome indicated modification to the IGF-1 receptor gene. Many killifish are lavishly coloured and most species are easy to keep and breed in an aquarium . Specimens can be obtained from specialist societies and associations. Striped panchax (also known as the Golden Wonder killifish) are commonly found in pet shops, but caution must be exercised when considering tank mates, since

1763-424: Was black. Its scales were oddly light coloured at their centre. The scales of the young were blotched. The Titicaca orestias became extinct due to competition by introduced trout like the lake trout , brown trout , or the rainbow trout as well as Argentinian silverside from the 1930s to the 1950s. A survey in 1962 failed to find any Titicaca orestias. Orestias cuvieri is a species of killfish that belongs in

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1806-489: Was the largest member in that genus. In the hope that an undiscovered population remains, it is listed as Critically Endangered , possibly extinct by the IUCN . Despite its common name, it is not the only Orestias from Lake Titicaca. Its mouth was nearly turned upwards, thereby giving the flat head a concave shape. The head took up nearly a third of the whole body length. The upperside was greenish-yellow to umber. The lower jaw

1849-448: Was the largest species in the genus. The maximum recorded size is 22 cm (8.7 in) in standard length and 27 cm (10.6 in) in total length, which is considerably larger than most other species; only O. pentlandii at up to 20 cm (7.9 in) and 23.5 cm (9.3 in), respectively, comes close. With regard to the coloration of the amanto during their lifetime, specimens present black melanophores laterally as

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