Hoplosternum
Encyclopedia
Hoplosternum is a small genus
of freshwater
catfish
in the Callichthyinae subfamily of the armored catfish
family, and consists of 3 species from South America
, H. littorale, H. magdalenae, and H. punctatum.
A fossil catfish has been identified as Hoplosternum sp. from the middle Miocene
in the La Venta
formation, Magdalena River
basin, Colombia
.
. The name Hoplosternum is derived from the Greek
hoplon (weapon) and sternon (chest).
Megalechis
was erected to accommodate M. thoracatum, previously a species of Hoplosternum, and a related species.
east of the Andes
and north of Buenos Aires
, including the Orinoco
, Trinidad
, coastal rivers of the Guianas, Amazon River
drainage, Paraguay
, lower Paraná River
, and coastal systems in southern Brazil
. One single lot is known from the upper Paraná River and the São Francisco River
drainage; it has been suggested that these occurrences may represent introduced populations
. This species has also been introduced into Florida
.
H. magdalenae occurs west of the Andes, in the Lake Maracaibo
basin in Venezuela
, and in the drainages of Sinu River
and Magdalena River
in Colombia
. Finally, H. punctatum is only found in the Atrato River
basin in Colombia and in the Pacific coastal drainages of Panama
, in southern Central America
.
Like other callichthyines, Hoplosternum species build bubble nest
s. Among callichthyines, H. littorale has the most complex nest structure.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
in the Callichthyinae subfamily of the armored catfish
Callichthyidae
Callichthyidae is a family of catfishes , called armored catfishes due to the two rows of bony plates running down the length of the body. This family contains some of the most popular freshwater aquarium fish, such as the Corydoras.-Taxonomy:The family derives its name from the Greek words kallis...
family, and consists of 3 species from South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, H. littorale, H. magdalenae, and H. punctatum.
A fossil catfish has been identified as Hoplosternum sp. from the middle Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
in the La Venta
La Venta
La Venta is a pre-Columbian archaeological site of the Olmec civilization located in the present-day Mexican state of Tabasco. Some of the artifacts have been moved to the museum "Parque - Museo de La Venta", which is in Villahermosa, the capital of Tabasco....
formation, Magdalena River
Magdalena River
The Magdalena River is the principal river of Colombia, flowing northward about through the western half of the country. It takes its name from the biblical figure Mary Magdalene. It is navigable through much of its lower reaches, in spite of the shifting sand bars at the mouth of its delta, as...
basin, Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
.
Taxonomy
The type species for this genus is Hoplosternum littoraleHoplosternum littorale
Hoplosternum littorale a species of catfish belonging to the Callichthyinae subfamily of the family Callichthyidae. It is known as tamuatá in Brazil, atipa in French Guiana, hassar in Guyana, kwi kwi in Suriname, cascadu in Trinidad, and busco or currito in Venezuela.-Description:H...
. The name Hoplosternum is derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
hoplon (weapon) and sternon (chest).
Megalechis
Megalechis
Megalechis is a small genus of freshwater catfish in the Callichthyinae subfamily of the armored catfish family, and consists of 2 species.-Taxonomy:The type species for this genus is Callichthys thoracatus...
was erected to accommodate M. thoracatum, previously a species of Hoplosternum, and a related species.
Distribution
H. littorale has the widest distribution of any callichthyid. It is present in all of South AmericaSouth America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
east of the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
and north of Buenos Aires
Buenos Aires
Buenos Aires is the capital and largest city of Argentina, and the second-largest metropolitan area in South America, after São Paulo. It is located on the western shore of the estuary of the Río de la Plata, on the southeastern coast of the South American continent...
, including the Orinoco
Orinoco
The Orinoco is one of the longest rivers in South America at . Its drainage basin, sometimes called the Orinoquia, covers , with 76.3% of it in Venezuela and the remainder in Colombia...
, Trinidad
Trinidad
Trinidad is the larger and more populous of the two major islands and numerous landforms which make up the island nation of Trinidad and Tobago. It is the southernmost island in the Caribbean and lies just off the northeastern coast of Venezuela. With an area of it is also the fifth largest in...
, coastal rivers of the Guianas, Amazon River
Amazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...
drainage, Paraguay
Paraguay River
The Paraguay River is a major river in south central South America, running through Brazil, Bolivia, Paraguay, and Argentina...
, lower Paraná River
Paraná River
The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...
, and coastal systems in southern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. One single lot is known from the upper Paraná River and the São Francisco River
São Francisco River
The São Francisco is a river in Brazil. With a length of , it is the longest river that runs entirely in Brazilian territory, and the fourth longest in South America and overall in Brazil...
drainage; it has been suggested that these occurrences may represent introduced populations
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
. This species has also been introduced into Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
.
H. magdalenae occurs west of the Andes, in the Lake Maracaibo
Lake Maracaibo
Lake Maracaibo is a large brackish bay in Venezuela at . It is connected to the Gulf of Venezuela by Tablazo Strait at the northern end, and fed by numerous rivers, the largest being the Catatumbo. It is commonly considered a lake rather than a bay or lagoon, and at 13,210 km² it would be the...
basin in Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
, and in the drainages of Sinu River
Sinú River
Sinú River , is a river in northwestern Colombia that flows mostly through the Córdoba Department and into the Caribbean. The river is the third most important river after the Magdalena River and the Cauca River in the Caribbean Region. It is born in the Antioquia Department, flowing south to north...
and Magdalena River
Magdalena River
The Magdalena River is the principal river of Colombia, flowing northward about through the western half of the country. It takes its name from the biblical figure Mary Magdalene. It is navigable through much of its lower reaches, in spite of the shifting sand bars at the mouth of its delta, as...
in Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
. Finally, H. punctatum is only found in the Atrato River
Atrato River
The Río Atrato is a river of northwestern Colombia. It rises in the slopes of the Western Cordillera and flows almost due north to the Gulf of Urabá , where it forms a large, swampy delta....
basin in Colombia and in the Pacific coastal drainages of Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, in southern Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
.
Ecology
Hoplosternum is normally found in large schools on the muddy bottoms of slow-moving rivers, pools, drainage ditches, and swampy areas. In water with low oxygen content, the fish are capable of utilizing atmospheric air by taking in a gulp of air at the surface of the water and passing it back to the hind gut. The walls of the gut are lined with tiny blood vessels into which the oxygen from the air can pass, similar to the function of true lungs. The remaining gasses pass out through the anus. When there is a severe drought, these air breathers are able to traverse short stretches of land seeking better conditions. The fish is also capable of making sounds; both grunts and squeaks.Like other callichthyines, Hoplosternum species build bubble nest
Bubble nest
Bubblenests, also spelled bubble nests or bubble-nests, created by some fish species, are floating masses of bubbles blown with an oral secretion, saliva bubbles, and occasionally aquatic plants, or an area for egg deposit attached at the bottom. Fish that build and guard bubble nests are known as...
s. Among callichthyines, H. littorale has the most complex nest structure.