Amphiarius
Encyclopedia
Amphiarius is a genus
of catfish
es (order
Siluriformes) of the family
Ariidae
. It includes two species
, the Kukwari sea catfish, A. phrygiatus, and the softhead sea catfish, A. rugispinis.
in 1840 as Arius
species, where they have been traditionally placed. They have also been classified in the genus Notarius
. Since then, it has been recognized that these two species form a natural, monophyletic
grouping and were suggested to represent a new, undescribed genus. The genus Amphiarius was finally erected for these two species in 2007.
, brackish
and fresh water
s of North
and eastern South America
. A. phrygiatus occurs in brackish estuaries with very low salinities, nearly entering freshwater, and is found on shallow muddy bottoms, ranging through Venezuela
, Guyana
, Surinam, French Guiana
, and Brazil
. A. rugispinis is coastal, found chiefly in turbid waters of estuaries and around river mouths; it originates from brackish and marine waters of Trinidad Island, Guyana, Surinam, French Guiana, and Brazil.
, while A. rugispinis grows to about 45 cm (18 in) TL.
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 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...
es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Ariidae
Ariidae
The Ariidae or ariid catfish are a family of catfish that mainly live in marine waters with many freshwater and brackish water species. They are found worldwide in tropical to warm temperate zones.-Taxonomy:...
. It includes two species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, the Kukwari sea catfish, A. phrygiatus, and the softhead sea catfish, A. rugispinis.
Taxonomy
A. phrygiatus and A. rugispinis were both originally described by Achille ValenciennesAchille Valenciennes
Achille Valenciennes was a French zoologist.Valenciennes was born in Paris, and studied under Georges Cuvier. Valenciennes' study of parasitic worms in humans made an important contribution to the study of parasitology...
in 1840 as Arius
Arius
Arius was a Christian presbyter in Alexandria, Egypt of Libyan origins. His teachings about the nature of the Godhead, which emphasized the Father's divinity over the Son , and his opposition to the Athanasian or Trinitarian Christology, made him a controversial figure in the First Council of...
species, where they have been traditionally placed. They have also been classified in the genus Notarius
Notarius
A notarius is a public secretary who is appointed by competent authority to draw up official or authentic documents . In the Roman Catholic Church there have been apostolic notaries and even episcopal notaries...
. Since then, it has been recognized that these two species form a natural, monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
grouping and were suggested to represent a new, undescribed genus. The genus Amphiarius was finally erected for these two species in 2007.
Distribution
Amphiarius species are distributed in marineMarine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
, brackish
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
and fresh water
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
s of North
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and eastern 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...
. A. phrygiatus occurs in brackish estuaries with very low salinities, nearly entering freshwater, and is found on shallow muddy bottoms, ranging through 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...
, Guyana
Guyana
Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
, Surinam, French Guiana
French Guiana
French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...
, and 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...
. A. rugispinis is coastal, found chiefly in turbid waters of estuaries and around river mouths; it originates from brackish and marine waters of Trinidad Island, Guyana, Surinam, French Guiana, and Brazil.
Description
Amphiarius are distinguished from all other ariids by the presence of accessory tooth plates that are small to moderate, roughly round, and laterally located. A. phrygiatus grows to about 30 centimetres (12 in) TLFish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
, while A. rugispinis grows to about 45 cm (18 in) TL.