Anablepidae is a family of freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 and brackish water fishes living on river estuaries from southern Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 to southern 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...

. There are three genera

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...

 with sixteen 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 four-eyed fish

Four-eyed fish

The four-eyed fishes are a genus, Anableps, of fishes in the family Anablepidae. They have eyes raised above the top of the head and divided in two different parts, so that they can see below and above the water surface at the same time...

es (genus Anableps), the onesided livebearer

Onesided livebearer

Jenynsia is a genus of freshwater fishes in the family Anablepidae. Like Anableps species, they are onesided livebearers: some sources indicate that they only mate on one side, right-"handed" males with left-"handed" females and vice versa. However other sources dispute this...

s (genus Jenynsia) and the white-eye

White-eye (fish)

The white-eye, Oxyzygonectes dovii, is a species of killifish of the family Anablepidae. This species is the only member of its genus Oxyzygonectes and the subfamily Oxyzygonectinae....

, Oxyzygonectes dovii. Fish of this family eat mostly 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...

s and other invertebrate

Invertebrate

An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s.

Reproduction

Fish in the subfamily Anablepinae are ovoviviparous

Ovoviviparity

Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...

. Curiously, they only mate on one side, right-"handed" males with left-"handed" females and vice versa. The male of most species in the family has specialized anal rays which are greatly elongated and fused into a tube called a gonopodium associated with the sperm duct which he uses as an intromittent organ

Penis

The penis is a biological feature of male animals including both vertebrates and invertebrates...

 to deliver sperm to the female.

Classification

The Anablepidae contains seventeen species, grouped into three genera, as follows:

Family Anablepidae

• Subfamily Anablepinae
  • Genus Anableps
    • Anableps anableps - Largescale foureyes
    • Anableps dowei - Pacific foureyed fish
    • Anableps microlepis - Foureyes
  • Genus Jenynsia
    • Jenynsia alternimaculata
    • Jenynsia diphyes
    • Jenynsia eigenmanni
    • Jenynsia eirmostigma
    • Jenynsia lineata
    • Jenynsia maculata
    • Jenynsia multidentata
    • Jenynsia onca
    • Jenynsia pygogramma
    • Jenynsia sanctaecatarinae
    • Jenynsia tucumana
    • Jenynsia unitaenia
    • Jenynsia weitzmani
• Subfamily Oxyxygonectinae
  • Genus Oxyzygonectes
    • Oxyzygonectes dovii - White-eye

Other References

• Berra, Tim M. (2001). Freshwater Fish Distribution. San Diego: Academic Press. ISBN 0-12-093156-7

External links

• Anableps anableps