Ossubtus xinguense
Encyclopedia
Ossubtus xinguense is a species
of serrasalmine
characin and is the only species of the genus
Ossubtus. It has an unusual downturned mouth that gives the appearance of a beak.
basin, but is restricted to the rapids area around Altamira City
, Pará
, Brazil
.
.
The body is ovoid. The profile of the snout is blunt. In young fish, the mouth is terminal (pointing forward); however, as the fish grows, the mouth turns downward and becomes strictly ventral in individuals larger than 5 cm (2 in) SL. This gives the mouth a beak-like appearance.
species. Young specimens of up to 4 cm (1.6 in) SL could be observed in schools of 20–30 individuals, sheltered under broad stones. This species is omnivorous. Shrimp, dead or alive, blood worm, vegetable matter, brine shrimp, daphnia etc, are foods this species will consume in captivity. In captivity, it exhibits high territoriality which results in a strong aggressiveness towards conspecifics. This species is parasitized by Anphiira xinguensis, an isopode of the family Cymothoidae
. This parasite lives in the gill chamber of the fish and also develops a contorted morphology
, presumably in response to its host's cursive ontogeny
. The female is far more dominant than the male and will often seek caves to which no other fish may enter. This is believed to be due to reproductive dominance (protecting the young), once a suitable breeding location is found the female will not surrender it.
.
O. xinguense is endemic to the rapids of Xingu River around Altamira City. The planned construction of a large hydroelectric plant
in the lower Xingu River at the limit of the rapids and the main Amazon floodplain may result in a highly negative impact to the population of O. xinguense and numerous other rheophilic (and apparently endemic) fish species occurring in the Xingu River rapids.
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...
of serrasalmine
Serrasalminae
Serrasalminae is a subfamily of fish within the family Characidae. The name means "serrated salmon family", which refers to the serrated keel running along the belly of these fish.-Common names:...
characin and is the only species of the genus
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...
Ossubtus. It has an unusual downturned mouth that gives the appearance of a beak.
Distribution
It originates from the Xingu RiverXingu River
The Xingu River , also called Rio Xingu, is a 1,230-mile long, river in north Brazil; it is a southeast tributary of the Amazon River.-Description and history:...
basin, but is restricted to the rapids area around Altamira City
Altamira, Pará
Altamira is a city in the state of Pará, in northern Brazil. It is the largest municipality in the Americas by area, and the second in the world, after Jiuquan, China...
, Pará
Pará
Pará is a state in the north of Brazil. It borders the Brazilian states of Amapá, Maranhão, Tocantins, Mato Grosso, Amazonas and Roraima. To the northwest it also borders Guyana and Suriname, and to the northeast it borders the Atlantic Ocean. The capital is Belém.Pará is the most populous state...
, 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...
.
Description
This species reaches 17.6 centimetres (6.9in) SLFish 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:...
.
The body is ovoid. The profile of the snout is blunt. In young fish, the mouth is terminal (pointing forward); however, as the fish grows, the mouth turns downward and becomes strictly ventral in individuals larger than 5 cm (2 in) SL. This gives the mouth a beak-like appearance.
Ecology
O. xinguense is a strictly rheophilicRheophile
A rheophile is an organism that prefers to live in fast moving water.-Insects:*Many aquatic insects living in riffles require current to survive.*Epeorus sylvicola, a rheophilic mayfly species .-Fish:...
species. Young specimens of up to 4 cm (1.6 in) SL could be observed in schools of 20–30 individuals, sheltered under broad stones. This species is omnivorous. Shrimp, dead or alive, blood worm, vegetable matter, brine shrimp, daphnia etc, are foods this species will consume in captivity. In captivity, it exhibits high territoriality which results in a strong aggressiveness towards conspecifics. This species is parasitized by Anphiira xinguensis, an isopode of the family Cymothoidae
Cymothoidae
Cymothoidae is a family of isopods. Several species are parasites, usually of fish. These include the bizarre "tongue-biter", Cymothoa exigua.-Genera:Around forty genera are recognised *Aegathoa Dana, 1853...
. This parasite lives in the gill chamber of the fish and also develops a contorted morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, presumably in response to its host's cursive ontogeny
Ontogeny
Ontogeny is the origin and the development of an organism – for example: from the fertilized egg to mature form. It covers in essence, the study of an organism's lifespan...
. The female is far more dominant than the male and will often seek caves to which no other fish may enter. This is believed to be due to reproductive dominance (protecting the young), once a suitable breeding location is found the female will not surrender it.
Conservation
This fish is endangered. However, it is not listed on the IUCN Red ListIUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
.
O. xinguense is endemic to the rapids of Xingu River around Altamira City. The planned construction of a large hydroelectric plant
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
in the lower Xingu River at the limit of the rapids and the main Amazon floodplain may result in a highly negative impact to the population of O. xinguense and numerous other rheophilic (and apparently endemic) fish species occurring in the Xingu River rapids.