''Arapaima agassizii'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of freshwater

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. It is a member of the arapaimas, a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of air-breathing fish that contains some of the world's largest freshwater fish. It is known only from a single now-lost holotype collected between 1817 and 1820 from an unspecified region in the lowlands of the Brazilian Amazon, and an 1847 description by Achille Valenciennes, based on notes & illustrations of the specimen made by Johann Baptist von Spix and

Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

in 1829. The holotype skeleton was kept at the Bavarian State Collection of Zoology and destroyed during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, but the species was redescribed in a 2013 review of wild-caught ''Arapaima'' specimens worldwide on the basis of Valenciennes' description, with the review finding sufficient morphological evidence that ''A. agassizii'' is distinct from all other species of arapaima. Due to the lack of knowledge about the origins of the specimen and the present status of the species, it is classified as data deficient by the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

References

Osteoglossidae Freshwater fish of Brazil Endemic fish of Brazil Fish of the Amazon basin Fish described in 1847 Taxa named by Achille Valenciennes {{Osteoglossiformes-stub