South American lungfish
Encyclopedia
The South American lungfish, Lepidosiren paradoxa, is the single species of lungfish
found in swamp
s and slow-moving waters of the Amazon
, Paraguay
, and lower Paraná River
basins
in South America
. Notable as an obligate
air-breather, it is the sole member of its family Lepidosirenidae. Relatively little is known about the South American lungfish.
Additional common name
s of this species include American mud-fish and scaly salamander-fish
. In Portuguese it is also known as piramboia, pirarucu-bóia, traíra-bóia and caramuru.
The immature lungfish is spotted with gold on a black background, in the adult, this fades to a brown or gray color. Its tooth-bearing premaxillary and maxillary
bones are fused like in all Dipnoi. South American lungfishes also share an autostylic jaw suspension (where the palatoquadrate
is fused to the cranium) and powerful adductor jaw muscles with the extant Dipnoi Like the African lungfishes, this species has an elongate, almost eel-like body. It may reach a length of 125 centimetres (4.1 ft). The pectoral fins are thin and threadlike, while the pelvic fins are somewhat larger, and set far back. The fins are connected to the shoulder by a single bone, which is a marked difference from most fish, whose fins usually have at least four bones at their base; and a marked similarity with nearly all land-dwelling vertebrates. The gills are greatly reduced and essentially non-functional in the adults.
Juvenile lungfish feed on insect
larvae and snail
s, while adults are omnivorous, adding algae
and shrimp
s to their diet, crushing them with their heavily mineralized tooth-plates. The fishes' usual habitats disappear during the dry season, so they burrow into the mud and make a chamber about 30-50 cm down, leaving a couple of holes to the surface for air. During this aestivation, they produce a layer of mucus to seal in moisture and slow their metabolism down greatly.
When the rainy season begins, they come out of hibernation and begin mating. The parents build a nest for the young, which resemble tadpole
s and have four external gill
s. In order to enrich the oxygen in the nest, the male develops highly vascularized structures on the pelvic fins that release additional oxygen into the water. The young become air-breathing at about 7 weeks. Juveniles have external threadlike gills very much like those of newts.
Lungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
found in swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
s and slow-moving waters of the Amazon
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...
, Paraguay
Paraguay River
The Paraguay River is a major river in south central South America, running through Brazil, Bolivia, Paraguay, and Argentina...
, and 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...
basins
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
in 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...
. Notable as an obligate
Obligate
Obligate means "by necessity" and is used mainly in biology in phrases such as:* Obligate aerobe, an organism that cannot survive without oxygen* Obligate anaerobe, an organism that cannot survive in the presence of oxygen...
air-breather, it is the sole member of its family Lepidosirenidae. Relatively little is known about the South American lungfish.
Additional common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
s of this species include American mud-fish and scaly salamander-fish
Salamanderfish
Lepidogalaxias salamandroides is a species of small fish of Western Australia. It is the only member of the family Lepidogalaxiidae and genus Lepidogalaxias. Common names for this fish include Salamanderfish and Shannon mudminnow...
. In Portuguese it is also known as piramboia, pirarucu-bóia, traíra-bóia and caramuru.
The immature lungfish is spotted with gold on a black background, in the adult, this fades to a brown or gray color. Its tooth-bearing premaxillary and maxillary
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
bones are fused like in all Dipnoi. South American lungfishes also share an autostylic jaw suspension (where the palatoquadrate
Palatoquadrate
In some fishes, the palatoquadrate is the dorsal component of the mandibular arch, the ventral one being Meckel's cartilage....
is fused to the cranium) and powerful adductor jaw muscles with the extant Dipnoi Like the African lungfishes, this species has an elongate, almost eel-like body. It may reach a length of 125 centimetres (4.1 ft). The pectoral fins are thin and threadlike, while the pelvic fins are somewhat larger, and set far back. The fins are connected to the shoulder by a single bone, which is a marked difference from most fish, whose fins usually have at least four bones at their base; and a marked similarity with nearly all land-dwelling vertebrates. The gills are greatly reduced and essentially non-functional in the adults.
Juvenile lungfish feed on insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
larvae and snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s, while adults are omnivorous, adding algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
s to their diet, crushing them with their heavily mineralized tooth-plates. The fishes' usual habitats disappear during the dry season, so they burrow into the mud and make a chamber about 30-50 cm down, leaving a couple of holes to the surface for air. During this aestivation, they produce a layer of mucus to seal in moisture and slow their metabolism down greatly.
When the rainy season begins, they come out of hibernation and begin mating. The parents build a nest for the young, which resemble tadpole
Tadpole
A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...
s and have four external gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s. In order to enrich the oxygen in the nest, the male develops highly vascularized structures on the pelvic fins that release additional oxygen into the water. The young become air-breathing at about 7 weeks. Juveniles have external threadlike gills very much like those of newts.