Piabucus dentatus | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Characiformes |
Family: | Iguanodectidae |
Genus: | Piabucus |
Species: | P. dentatus |
Binomial name | |
Piabucus dentatus Kölreuter, 1763 | |
Piabucus dentatus, also called the chin tetra or the coastal piabucus, is a small freshwater fish from the rivers of South America. It has a wide range that includes multiple coastal drainage systems, and was once mistakenly cited from Peru. Preferred habitats are generally high in silt content and are slow-moving, including floodplain streams and estuaries.
It is one of the earliest known South American fish in Northern ichthyology, believed to have been recorded first in 1648. It did not have a standard scientific name until 1766, though it had an earlier description in 1763 without a binomial moniker. German botanist Joseph Gottlieb Kölreuter was responsible for the 1763 description, while Swedish taxonomist Carl Linnaeus prescribed its first true scientific name - Salmo argentinus - in 1766.
Piabucus dentatus reaches a maximum length of 12.9 cm (5.1 in) SL (standard length), [2] which makes it the largest of its genus. [3] It has a generally slender body with a deep chest and long pectoral fins, which are characteristics that differentiate Piabucus from sister genus Iguanodectes . [4] It is elongated and slight, with a compressed "torpedo" shape. [5] It has a generally silvery color with a dark lateral stripe; its scales may reflect blue light ventrally, and its lateral line may contain yellow-gold and green. [6] Congener Piabucus melanostoma has a distinctive patch of dark coloration on the lower jaw often absent in related species, but similar markings can be found on some specimens of P. dentatus. [7] [8]
The presence of an adipose fin can be used to differentiate P. dentatus from its similar congeners. Notable morphometric characteristics include 80-84 perforated scales in the lateral line, 11 dorsal-fin rays, and 45-46 anal-fin rays. [8] The dorsal and ventral fins are short, and the middle rays of the caudal fin are often pigmented, but the fins otherwise lack markings. [7] Juvenile P. dentatus have rounder heads, smaller mouths, and a body that is proportionally elongate. Starting at a length of roughly 2 cm, juveniles start to resemble small adults. [9]
Sexual dimorphism is minor in P. dentatus, but present. Males tend to reach larger measurements in SL than females, and the anal fin is longer, with the last branched fin-ray reaching past the origin of the caudal fin. The anal fin is also more robust in males - specifically, the scaled anal-fin rays (lepidotrichia, meaning "scaled hair") are thicker, with sturdier segments (hemitrichia, meaning "partial hair") in the halves that make them up. [10] Males from all three species of Piabucus also develop lappets (fleshy extensions) and small hooks on the foremost few rays of the anal fin. [11]
Piabucus dentatus was the only member of the genus Piabucus upon introduction in 1817 by German biologist Lorenz Oken. [12] P. dentatus became the type species therein by way of monotypy. [13] Prior, P. dentatus was referred to as Salmo argentinus. When first described by Joseph Gottlieb Kölreuter in 1763, P. dentatus did not have a binomial name, though Kölreuter did introduce the now-obsolete genus Piabucu. [14] [15] [16] Piabucu was based on the work of German naturalist Georg Marcgrave, in his 1648 book Historia Naturalis Brasiliae . [17] [18] Marcgrave's Piabucu is considered in modern research to be equivalent to P. dentatus, making it one of the earliest-recorded South American fishes in Northern ichthyology. [19] [20]
There are multiple reports that the baisonym of P. dentatus is Trutta dentata, [21] [22] partially because American ichthyologist James Erwin Böhlke reported as much in a 1954 paper. [23] Subsequently, French ichthyologist Jacques Géry did the same in a paper from 1972. [24] However, "trutta dentata" is a Latin term that means "toothed trout", and was not a scientific name in the strictest sense; rather, it is an outdated label for classifying fish, and comes in opposition to "trutta edentula", which means "toothless trout", wherein "trout" was generally used to refer to morphology as opposed to phylogeny. [25] (To this day, dentition - or lack thereof - remains a morphometric feature that can be used to differentiate fish species of similar superficial appearance.) [26]
Furthermore, the Biodiversity Heritage Library has records of the phrase "trutta dentata" dating back to the year 1740, [27] but "trutta" as a genus was not in use by ichthyologists until 1764, named by French zoologist François Alexandre Pierre de Garsault. [28] P. dentatus could not have realistically been considered a member of genus Trutta in 1763, because Trutta did not exist in the generic sense; rather, it was more of a rough grouping, without the standardization of modern taxonomy. (The genus Trutta is now considered obsolete, having been synonymized with genus Salmo .) [28] As such, its true baisonym is most likely Salmo argentinus, prescribed by Swedish taxonomist Carl Linnaeus in 1766. [13] The report from Koelreuter in 1763 remains its original description, despite the species not having a standard name at the time. [16] [29]
The specific epithet "dentatus" refers to the dense set of 16 teeth present at the end of each mandible, as "dentatus" means "teeth". "Piabucus" is a Latinization of the Brazilian word "piabucu", which was and is used to refer to various small fishes of similar appearance. [25]
The common name "chin tetra" actually originates in markings seen on Piabucus melanostoma. P. melanostoma has a dark patch on the lower jaw, but is otherwise similar to its congeners, which means that all three are sometimes referred to by the same common name. [30] The common name "coastal piabucus" comes from the fact that P. dentatus is common in estuaries and brackish waters along the northeastern coast of South America. [1]
Piabucus dentatus is a coastal dweller, found in river drainages from Venezuela's Paria Gulf to the mouth of the Amazon river. It demonstrates a preference for silty, turbid waters, including estuaries, floodplain streams, and various river tributaries, which places it in some brackish environments. Ichthyologist Carl H. Eigenmann once mistakenly cited it from Peru, and further instances from Bolivia are misidentifications. [1] [2] Though infrequent, it is found in Suriname. [31]
Examination of stomach contents has shown that P. dentatus is a generalist feeder with a preference for algae and decaying plant matter, though it also targets microscopic invertebrates. [32] Its varied diet earns it different classifications across various studies; it is classified as a detritivore based on its consumption of leaf litter, [33] a micropredator based on its consumption of micro-invertebrates, [1] or an algivore based on its consumption of various types of algae. [34]
Piabucus dentatus is known to be a schooling fish with a non-confrontational temperament. [35] It tends to dwell near the surface of the water, and is often an active swimmer. [20] Little is known of specific reproductive habits, but aspects of its biology indicate that it is likely an egg-scattering species that does not guard its young. [1]
While P. dentatus is known from the aquarium trade, [1] and congeners are also seen in the industry, [30] information on species-specific behavior and care is somewhat limited. Hobbyists report a generally pleasant disposition, but its large size in comparison to other aquarium tetras results in an intimidating presence for smaller fishes; [35] still, it is often an appropriate addition to a community tank. [5] It is known to be a generalist feeder that will accept most flake and pellet food, as well as biting at soft-leaved aquarium plants and hair algae. [35] [36]
Piabucus dentatus is considered a species of least concern by the IUCN. [1] While it lives in habitats under various anthropogenic pressures, including dam construction, oil drilling, and infrastructural development, there is no evidence of an immediate population threat. For instance, one study demonstrated that hydroelectric dam construction decreased general species diversity, but P. dentatus in particular seemed to suffer only mild consequences. [34]
The rummy-nose tetra is a species of tropical freshwater characin fish originating in South America, popular among fishkeepers as a tropical aquarium fish. One of many small tetras belonging to the same genus, it is on average 5 cm (2 in) long when fully grown. The fish is one of several very similar species including Petitella bleheri, and Petitella georgiae, and it is possible that more recently collected specimens available in the aquarium trade are members of one or other of these similar species. The common name applied to most of these fishes is "rummy-nose tetra", though other common names are in circulation.
Bryconops is a genus of freshwater fish in the family Iguanodectidae from South America. It consists of small fish, all under half-a-foot long, with slender bodies and silvery scales, though there is some mild color variation. Several species can be identified by way of a humeral patch, and others have a reddish ocellus, or eyespot, on one or both lobes of the dorsal fin.
Iguanodectes is a genus of freshwater fish found in tropical South America, with eight currently described species. They are all small tetras, none longer than 5 inches, and often have attractive silvery or striped scales, which makes them a target for the ornamental fish industry. Alongside the genus Piabucus, it is in the subfamily Iguanodectinae, which in turn is in the family Iguanodectidae. The genus Bryconops, which is also in Iguanodectidae, makes up a sister clade to Iguanodectinae.
Piabucus is a genus of freshwater tetras in the family Iguanodectidae. All three species are found in South America, largely the Amazon and its major tributaries. None of them are longer than half a foot long, with the largest reaching a maximum size of 12.9 cm (5.1 in), and they are slender, with relatively deep chests and long pectoral fins. Their scales are pale or silvery, with lateral lines that stand out.
Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It is home to the subfamily Iguanodectinae and the monotypic Bryconops clade. Several species in the family, such as the green line lizard tetra, the tailspot tetra, and the orangefin tetra, are sometimes taken as aquarium fish.
Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. It has two genera, Piabucus and Iguanodectes. Some species in the subfamily are taken from the wild for aquariums, like the red- and green-line lizard tetras. There is minor, but ongoing, debate regarding its taxonomy.
Bryconops alburnoides is a small freshwater fish, approximately 6 inches long at its largest, that lives in the rivers of South America. It has a slender body, with a yellowish dorsal fin and yellow-tinged back scales that fade into silver on its belly. It is largely an insectivore that picks land-dwelling insects from the riverbanks, though it eats much more whenever rain washes prey into the water.
The tailspot tetra is a freshwater fish that lives in the coastal river regions of upper South America. Both its common and scientific names reference the distinct spot of color present on the tail fin, which is one of its defining characteristics. It is a small fish, reaching 4.8 in at its longest. Despite its small size, it is an active swimmer, with a preference for fast-flowing waters.
Bryconops colanegra is a small, slender-bodied species of freshwater fish from South America, about 3.5 in long. It has a black tail fin that bears hints of red, and its scales are dark along the back, transitioning to a silver belly. It is endemic to a single river system in Venezuela, the Rio Caroní.
Bryconops melanurus, sometimes called the tail-light tetra, is a small species of freshwater fish from South America that primarily preys on insects. It lives in small schools and is an active swimmer, which means that it requires open space in its habitat. Nonetheless, it does not demonstrate a strong preference for any one biotope within its native range.
Bryconops allisoni is a species of freshwater fish known from the rivers of Brazil. It is a recent addition to the genus (2019), currently considered a member incertae sedis. Its name honors Antonio Machado-Allison, an ichthyologist responsible for a great deal of work on the genus Bryconops.
Iguanodectes adujai is a species of freshwater fish that inhabits the rivers of South America. It largely prefers slow-moving blackwater habitats, though it has a slender body that suggests a further affinity for flowing water. It has a distinct lateral stripe in two horizontal sections, with bright-red at the top and yellow at the bottom.
Iguanodectes geisleri, the red-line lizard tetra, is a species of freshwater fish from South America. It is a small species, largely herbivorous with some omnivorous traits, that prefers to live in schools and is partial to shallow waters, especially in blackwater habitats. Some aspects of its body plan are unique amongst its genus, including the position and length of the anal fin.
Iguanodectes purusii is a small freshwater fish from the rivers of South America. It is largely herbivorous, and prefers to live in schools. The name "purusii" originates from the species' type locality, the Purus river basin of Brazil, with a range that also extends into Peru. Furthermore, it has been documented from the Amazon, Madeira, Guaporé, and Pastaza rivers, but specific study of its ecology is otherwise lacking.
Iguanodectes spilurus, the green-line lizard tetra, is a small characiform fish from the rivers of South America. It is not a well-studied species, but research is available, including data from hobbyists that keep it as an ornamental fish. It has a distinct lateral stripe of reflective-green scales, and lacks any red markings therein; red is common in congeners' lateral stripes.
Iguanodectes variatus is a small freshwater fish, described from the rivers of South America in 1993. It has a minor presence in the aquarium trade, but lacks the popularity that would make excessive wild capture a legitimate threat. That being said, the threats facing South American aquatic environments are of ongoing concern for the associated biodiversity. Still, I. variatus has been recorded from various rivers and has shown general adaptability to its environment, which speaks to a high survivability.
Piabucus caudomaculatus is a small freshwater fish inhabiting the rivers of South America. It was the first member of the family Iguanodectidae to be reported from Bolivia, and it remains endemic to the region, found solely in the Mamoré river basin. It displays a preference for slow-moving waterways and has a largely insectivorous diet.
Piabucus melanostoma, sometimes called the chin tetra, is a small species of freshwater fish from the rivers of South America. It is the second-largest species of the genus, but still only reaches about 12 cm long. Occasionally found in captivity, it has an appealing iridescent-silver coloration. It is amongst the largest of fish still considered "tetras" in the aquarium hobby.
Astyanax angustifrons, sometimes referred to as the Campeche tetra, is a small freshwater fish from the rivers of Central and South America. It has a healthy distribution across southern Mexico and northern Guatemala, and is relatively common within its native range. Details regarding its diet and behavior are sparse, but it lives in areas with plentiful riparian vegetation, and most other members of the genus are omnivorous. Its habitat includes places affected by pollution and human activity; nonetheless, it is not endangered.
Astyanax bransfordii, sometimes called the longjaw tetra, is a small carnivorous species of fish endemic to a handful of lakes and slow-moving canals in Central America. Its range includes Lake Nicaragua and Lake Managua, which are two of the largest freshwater bodies in Central America; because it occurs only in the relevant areas of Costa Rica and Nicaragua, the area it actually inhabits is somewhat restricted. Its diet largely consists of various invertebrates and smaller fish. This is in contrast to various other species of Astyanax, which are more often omnivorous.
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