''Tomeurus gracilis'' is a species of
poeciliid fish native to
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
, in Brazil, Surinam and Venezuela. This species grows to a length of
TL.
It is the only known member of its
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 ...
.
This species is classified in the
tribe
The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...
Cnesterodontini in the 5th edition of
Fishes of the World
''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...
,
but more recent classifications place it as the only member of the subfamily Tomeurinae, the facultative viviparous poeciliids.
This is a sociable fish which lives in small schools consisting of several dozens of fishes. It is found in muddy creeks or along the sandy-muddy edges of shallow estuaries. It has been observed remaining still just below the surface but it prefers to hide beneath aquatic plants. Fertilisation is internal and, uniquely among the
Poeciliinae, the females may then lay eggs placing them individually onto aquatic plants. They can also be facultively
ovoviviparous.
[
]
References
Poeciliidae
Freshwater fish of South America
Ray-finned fish genera
Monotypic freshwater fish genera
Taxa named by Carl H. Eigenmann
{{Poeciliidae-stub