28-462: The Rio Grande silvery minnow or Rio Grande minnow ( Hybognathus amarus ) is a small herbivorous North American fish. It is one of the seven North American members of the genus Hybognathus , in the cyprinid family. The Rio Grande silvery minnow is one of the most endangered fish in North America, according to the U. S. Fish and Wildlife Service (USFWS). They were classified as endangered in
56-459: A free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism . In most cases this involves protogyny , fish starting life as females and converting to males at some stage, triggered by some internal or external factor. Protandry , where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization . Of
84-536: A great rate. The minnow now numbers way below its 1994 population, and is found in only 5 percent of its former habitat. Alterations of the Rio Grande include not only the modification of the flow of water by dams and channels but also the unintentional polluting of the quality of the water. This pollution can be originated from many factors, the major ones being, effluents by the military and industrial companies as well as wastewater from cities and nearby towns. In 2000,
112-726: A trait still present in Holostei ( bowfins and gars ). In some fish like the arapaima , the swim bladder has been modified for breathing air again, and in other lineages it have been completely lost. The teleosts have urinary and reproductive tracts that are fully separated, while the Chondrostei have common urogenital ducts, and partially connected ducts are found in Cladistia and Holostei. Ray-finned fishes have many different types of scales ; but all teleosts have leptoid scales . The outer part of these scales fan out with bony ridges, while
140-610: Is a stub . You can help Misplaced Pages by expanding it . Ray-finned fish Actinopterygii ( / ˌ æ k t ɪ n ɒ p t ə ˈ r ɪ dʒ i aɪ / ; from actino- 'having rays' and Ancient Greek πτέρυξ (ptérux) 'wing, fins'), members of which are known as ray-finned fish or actinopterygians , is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin supported by radially extended thin bony spines called lepidotrichia , as opposed to
168-458: Is a mixture of sand, gravel and silt. The breeding goal of the $ 1.7 million facility was to produce 50,000 minnows this year - with 25,000 minnows to be returned to the river and 25,000 to be retained for future captive spawning. The actual numbers are much higher. This project is the recipient of the Association of Conservation Engineers 2003 Award of Excellence (top honor/national design award) and
196-482: Is believed to consist of river plants and benthic macroinvertabrates, though there is little research into their diet due to the difficulty of getting into their stomachs. They play a role in keeping water clean by eating bad algae. Silvery minnows tend to skim the bottom of rivers and stream, and are prolific spawners. They serve as food source for other animals. The Rio Grande Silvery Minnow's eggs hatch in about 24 hours into larvae that can swim in just 3 to 4 days. It
224-540: Is divided into the infraclasses Holostei and Teleostei . During the Mesozoic ( Triassic , Jurassic , Cretaceous ) and Cenozoic the teleosts in particular diversified widely. As a result, 96% of living fish species are teleosts (40% of all fish species belong to the teleost subgroup Acanthomorpha ), while all other groups of actinopterygians represent depauperate lineages. The classification of ray-finned fishes can be summarized as follows: The cladogram below shows
252-542: Is no surprise that a species so programmed for survival once dominated a biological niche that spanned 3,000 meandering miles (4,825 kilometers) from New Mexico to Texas. The Rio Grande silvery minnow was first listed on July 20, 1994. It is currently designated as Endangered in the Entire Range. The population decline of the Rio Grande Silvery Minnow has been almost directly proportional to recent alterations to
280-432: Is relatively rare and is found in about 6% of living teleost species; male care is far more common than female care. Male territoriality "preadapts" a species for evolving male parental care. There are a few examples of fish that self-fertilise. The mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to
308-500: The Cyprinidae (in goldfish and common carp as recently as 14 million years ago). Ray-finned fish vary in size and shape, in their feeding specializations, and in the number and arrangement of their ray-fins. In nearly all ray-finned fish, the sexes are separate, and in most species the females spawn eggs that are fertilized externally, typically with the male inseminating the eggs after they are laid. Development then proceeds with
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#1732855485127336-481: The oviparous teleosts, most (79%) do not provide parental care. Viviparity , ovoviviparity , or some form of parental care for eggs, whether by the male, the female, or both parents is seen in a significant fraction (21%) of the 422 teleost families; no care is likely the ancestral condition. The oldest case of viviparity in ray-finned fish is found in Middle Triassic species of † Saurichthys . Viviparity
364-651: The sister lineage of all other actinopterygians, the Acipenseriformes (sturgeons and paddlefishes) are the sister lineage of Neopterygii, and Holostei (bowfin and gars) are the sister lineage of teleosts. The Elopomorpha ( eels and tarpons ) appear to be the most basal teleosts. The earliest known fossil actinopterygian is Andreolepis hedei , dating back 420 million years ( Late Silurian ), remains of which have been found in Russia , Sweden , and Estonia . Crown group actinopterygians most likely originated near
392-638: The Best Civil/Infrastructure New Mexico Project for the Best of 2003 Awards from Southwest Contractor magazine. Hybognathus see text Hybognathus is a genus of ray-finned fish in the family Cyprinidae . Its members are collectively known as the silvery minnows . Hybognathus are pelagophils that are native to North America. The populations of such pelagophils, including species of Hybognathus, continue to decrease in their natural habitats. This Leuciscidae article
420-468: The City of Albuquerque's Biological Park. The facility consists of a 50,000 gallon outdoor refugium as well as a 3,500 SF building with tiers of aquarium tanks that contain tens of thousands of baby minnows, each no more than a sixth of an inch long. The donut-shaped outdoor pond varies in depth from about one inch to two feet. Pumps control the current to mimic the natural flows of the Rio Grande. The bottom surface
448-470: The Rio Grande over the past century. There have been multiple diversions for municipal and agricultural use; alteration of the natural hydrograph (no spring runoff to cue spawning); habitat degradation from river narrowing and canalization; and construction of diversion dams which prevent migration. Even with the Rio Grande Silvery Minnow’s listing in 1994, its population has continued to drop at
476-505: The Service's New Mexico Fishery Resources Office. Biologists then either return the resulting fish to the Rio Grande or hold them for captive propagation. as taken from the Van H. Gilbert Architect PC official page: Van H. Gilbert Architect PC, in association with FishPro, developed conceptual and final design for a naturalized refugium for propagation of the endangered Rio Grande silvery minnow at
504-476: The U.S. Fish and Wildlife Service initiated a silvery minnow egg salvage pilot project. Biologists from the Service, Bureau of Reclamation, and University of New Mexico collect minnow eggs as well as reproductively-ready adult minnows near Elephant Butte, where these efforts do not disturb upstream populations. Captured adult minnows are induced to spawn, either at the Albuquerque Biological Park or
532-730: The U.S. in 1994, and now are found in less than 5 percent of their natural habitat in the Rio Grande . Historically, the minnow was found from Española, New Mexico, to the Gulf of Mexico in Texas. Now it can only be seen between Cochiti Dam and Elephant Butte Reservoir .they can also be found in a small pond in North Carolina It is a stout silvery minnow with moderately small eyes and a small mouth. Adults may reach 3.5 inches (89 mm) in total length. Rio Grande silvery minnows are herbivores whose diet
560-402: The adjacent diagram. The swim bladder is a more derived structure and used for buoyancy . Except from the bichirs , which just like the lungs of lobe-finned fish have retained the ancestral condition of ventral budding from the foregut , the swim bladder in ray-finned fishes derives from a dorsal bud above the foregut. In early forms the swim bladder could still be used for breathing,
588-463: The bichirs and holosteans (bowfin and gars) in having gone through a whole-genome duplication ( paleopolyploidy ). The WGD is estimated to have happened about 320 million years ago in the teleosts, which on average has retained about 17% of the gene duplicates, and around 180 (124–225) million years ago in the chondrosteans. It has since happened again in some teleost lineages, like Salmonidae (80–100 million years ago) and several times independently within
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#1732855485127616-440: The bulkier, fleshy lobed fins of the sister class Sarcopterygii (lobe-finned fish). Resembling folding fans , the actinopterygian fins can easily change shape and wetted area , providing superior thrust-to-weight ratios per movement compared to sarcopterygian and chondrichthyian fins. The fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the articulation between these fins and
644-706: The different actinopterygian clades (in millions of years , mya) are from Near et al., 2012. Jaw-less fishes ( hagfish , lampreys ) [REDACTED] Cartilaginous fishes ( sharks , rays , ratfish ) [REDACTED] Coelacanths [REDACTED] Lungfish [REDACTED] Amphibians [REDACTED] Mammals [REDACTED] Sauropsids ( reptiles , birds ) [REDACTED] Polypteriformes ( bichirs , reedfishes ) [REDACTED] Acipenseriformes ( sturgeons , paddlefishes ) [REDACTED] Teleostei [REDACTED] Amiiformes ( bowfins ) [REDACTED] Lepisosteiformes ( gars ) [REDACTED] The polypterids (bichirs and reedfish) are
672-432: The fish's habit of spending long periods out of water in the mangrove forests it inhabits. Males are occasionally produced at temperatures below 19 °C (66 °F) and can fertilise eggs that are then spawned by the female. This maintains genetic variability in a species that is otherwise highly inbred. Actinopterygii is divided into the subclasses Cladistia , Chondrostei and Neopterygii . The Neopterygii , in turn,
700-544: The highest mountain streams . Extant species can range in size from Paedocypris , at 8 mm (0.3 in); to the massive ocean sunfish , at 2,300 kg (5,070 lb); and to the giant oarfish , at 11 m (36 ft). The largest ever known ray-finned fish, the extinct Leedsichthys from the Jurassic , has been estimated to have grown to 16.5 m (54 ft). Ray-finned fishes occur in many variant forms. The main features of typical ray-finned fish are shown in
728-438: The inner part is crossed with fibrous connective tissue. Leptoid scales are thinner and more transparent than other types of scales, and lack the hardened enamel - or dentine -like layers found in the scales of many other fish. Unlike ganoid scales , which are found in non-teleost actinopterygians, new scales are added in concentric layers as the fish grows. Teleosts and chondrosteans (sturgeons and paddlefish) also differ from
756-425: The internal skeleton (e.g., pelvic and pectoral girdles). The vast majority of actinopterygians are teleosts . By species count, they dominate the subphylum Vertebrata , and constitute nearly 99% of the over 30,000 extant species of fish . They are the most abundant nektonic aquatic animals and are ubiquitous throughout freshwater and marine environments from the deep sea to subterranean waters to
784-461: The main clades of living actinopterygians and their evolutionary relationships to other extant groups of fishes and the four-limbed vertebrates ( tetrapods ). The latter include mostly terrestrial species but also groups that became secondarily aquatic (e.g. whales and dolphins ). Tetrapods evolved from a group of bony fish during the Devonian period . Approximate divergence dates for
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