Onesided livebearer
Encyclopedia
Jenynsia is a genus
of freshwater
fish
es 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. These fish are viviparous.
Basin and Atlantic coastal drainages from Río Negro Province
, Argentina
, to the city of Rio de Janeiro
, Brazil
, and in the Andean
drainages of northwest Argentina and southern Bolivia
.
to the genus Anableps and both are classified in the subfamily Anablepinae; together with the genus Oxyzygonectes they compose the family Anablepidae. Jenynsia contains two subgenera. Members of the subgenus Plesiojenysia Ghedotti, 1998, are distributed in the uplands of southern Brazil. Members of the subgenus Jenynsia are more widely distributed in southern South America, with one species, J. sanctaecatarinae also found in the uplands of southern Brazil. Members of the two subgenera are partially sympatric in southeastern Brazil.
gonopodium formed chiefly by the third, sixth, and seventh anal-fin rays and by the possession of tricuspid
teeth in the outer mandibular series in adults. The maximum length in these species is up to 12 centimetres (5 in) in females and about 4 cm (2 in) in males.
Subgenus Jenynsia
Subgenus Plesiojenynsia Ghedotti, 1998
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 freshwater
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...
fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es in 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...
Anablepidae
Anablepidae
Anablepidae is a family of freshwater and brackish water fishes living on river estuaries from southern Mexico to southern South America. There are three genera with sixteen species: the four-eyed fishes , the onesided livebearers and the white-eye, Oxyzygonectes dovii...
. 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. These fish are viviparous.
Distribution
Species of the genus are distributed in the Río de la PlataRío de la Plata
The Río de la Plata —sometimes rendered River Plate in British English and the Commonwealth, and occasionally rendered [La] Plata River in other English-speaking countries—is the river and estuary formed by the confluence of the Uruguay River and the Paraná River on the border between Argentina and...
Basin and Atlantic coastal drainages from Río Negro Province
Río Negro Province
Río Negro is a province of Argentina, located at the northern edge of Patagonia. Neighboring provinces are from the south clockwise Chubut, Neuquén, Mendoza, La Pampa and Buenos Aires. To the east lies the Atlantic Ocean.Its capital is Viedma...
, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, to the city of Rio de Janeiro
Rio de Janeiro
Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...
, 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...
, and in the Andean
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
drainages of northwest Argentina and southern Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
.
Taxonomy
Jenynsia is the sister groupCladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
to the genus Anableps and both are classified in the subfamily Anablepinae; together with the genus Oxyzygonectes they compose the family Anablepidae. Jenynsia contains two subgenera. Members of the subgenus Plesiojenysia Ghedotti, 1998, are distributed in the uplands of southern Brazil. Members of the subgenus Jenynsia are more widely distributed in southern South America, with one species, J. sanctaecatarinae also found in the uplands of southern Brazil. Members of the two subgenera are partially sympatric in southeastern Brazil.
Description
Unlike their cousins Anableps, their eyes are normal. Jenynsia species are diagnosable by the possession of an unscaled tubulargonopodium formed chiefly by the third, sixth, and seventh anal-fin rays and by the possession of tricuspid
Cusp (dentistry)
A cusp is an occlusal or incisal eminence on a tooth.Canine teeth, otherwise known as cuspids, each possess a single cusp, while premolars, otherwise known as bicuspids, possess two each. Molars normally possess either four or five cusps...
teeth in the outer mandibular series in adults. The maximum length in these species is up to 12 centimetres (5 in) in females and about 4 cm (2 in) in males.
Species
Subgenera and species according to Ghedotti, 2001 and Lucinda et al., 2006.Subgenus Jenynsia
- Jenynsia alternimaculata (FowlerHenry Weed FowlerHenry Weed Fowler was an American zoologist born in Holmesburg, Pennsylvania.He studied at Stanford University under David Starr Jordan...
, 1940) - Jenynsia lineata (Jenyns, 1842)
- Jenynsia maculata Regan, 1906
- Rio de la Plata onesided livebearer, Jenynsia multidentata (Jenyns, 1842)
- Jenynsia onca Lucinda, Reis & Quevedo, 2002
- Jenynsia pygogramma BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1902 - Jenynsia sanctaecatarinae Ghedotti & Weitzman, 1996
- Jenynsia tucumana Aguilera & Mirande, 2005
Subgenus Plesiojenynsia Ghedotti, 1998
- Jenynsia diphyes Lucinda, Ghedotti & Graça, 2006
- Jenynsia eigenmanni (Haseman, 1911)
- Jenynsia eirmostigma Ghedotti & Weitzman, 1995
- Jenynsia unitaenia Ghedotti & Weitzman, 1995
- Jenynsia weitzmani Ghedotti, Meisner & Lucinda, 2001