Rivulus
Encyclopedia
Rivulus is a genus of freshwater fish
in the Rivulidae
family
of Cyprinodontiformes
. Over one hundred species
of Rivulus have been described to date, some of them finding a degree of popularity among aquarists, especially killifish
fanciers. The genus was erected by Cuban
zoologist Felipe Poey
in 1860 with the type species
, Rivulus cylindraceus.
among the species in the genus. Males are generally more colorful or more intricately patterned. Females of many species display an ocellus
at the upper base of the caudal fin. This is commonly known among aquarists as 'the rivulus spot'.。It has also been found out that Rivulus killfish is one of the very few uncommon species that has both male and female genitals present on the same body. This means they are capable of producing offsprings by internally ovulating into themselves.
and as far south as Argentina
, including Central America
, the Caribbean Islands, the Guiana Shield and the Amazon Basin
. Throughout this range various species occupy lakes, ponds and streams in either sunny savannah
or shaded forest habitats, most often in shallow waters. The species of this genus are non-annual. Rivulus, together with the closely related genera Prorivulus (erected in 2004 and containing a single species) and Kryptolebias (erected in 2004, comprising species formerly assigned to Rivulus), contain the only species in the family Rivulidae to inhabit perennial aquatic biotopes.
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...
in the Rivulidae
Rivulidae
Rivulidae are a family of killifishes in the order Cyprinodontiformes. They are commonly known as rivulids, South American killifish or New World killifish. The latter names are slightly misleading however, as they are neither restricted to South America – though most are in fact found there...
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...
of Cyprinodontiformes
Cyprinodontiformes
The Cyprinodontiformes is an order of ray-finned fish, comprising mostly small, fresh-water fish. Many popular aquarium fish, such as killifish and live-bearers, are included. They are closely related to the Atheriniformes and are occasionally included with them...
. Over one hundred 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...
of Rivulus have been described to date, some of them finding a degree of popularity among aquarists, especially killifish
Killifish
A killifish is any of various oviparous cyprinodontiform fish . Altogether, there are some 1270 different species of killifish, the biggest family being Rivulidae, containing more than 320 species...
fanciers. The genus was erected by Cuban
Cubans
Cubans or Cuban people are the inhabitants or citizens of Cuba. Cuba is a multi-ethnic nation, home to people of different ethnic and national backgrounds...
zoologist Felipe Poey
Felipe Poey
-Biography:Poey was born in Havana, the son of French and Spanish parents. He spent several years of his life in Pau then studied law in Madrid. He became a lawyer in Spain but was forced to leave due to his liberal ideas, returning to Cuba in 1823. He began to concentrate on the study of the...
in 1860 with the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, Rivulus cylindraceus.
Description
The members of this genus generally have long, cylindrical bodies, relatively short fins and rounded caudals. A minority of species, such as R. lyricauda, R. mahdiaensis and R. rectocaudatus, possess rectangular or lyre-shaped caudals. Individual species range in size from barely one inch long to over four inches. They are colored variously, many species being quite subdued in color with bright hues being notably absent, such as in R. atratus. However, the genus also includes numerous vividly colored species, such as R. strigatus, R. xiphidius and R. agilae, that are patterned with brilliant jewel-toned hues that are often iridescent. Rivulus frequently remain motionless for long periods of time, backs arched and tails pointed downward, and then dart suddenly to another location. They are all renowned jumpers and can remain out of water for long periods. There is a range of sexual dimorphismSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
among the species in the genus. Males are generally more colorful or more intricately patterned. Females of many species display an ocellus
Ocellus
A simple eye refers to a type of eye design or optical arrangement that contains a single lens which detect light. A "simple eye" is so-called in distinction from a multi-lensed "compound eye", and is not necessarily at all simple in the usual sense of the word...
at the upper base of the caudal fin. This is commonly known among aquarists as 'the rivulus spot'.。It has also been found out that Rivulus killfish is one of the very few uncommon species that has both male and female genitals present on the same body. This means they are capable of producing offsprings by internally ovulating into themselves.
Distribution and habitat
Rivulus is the most geographically widespread genus of Neotropical aplocheiloid killifishes. Species are distributed as far north as MexicoMexico
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...
and as far south as 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...
, including Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, the Caribbean Islands, the Guiana Shield and the Amazon Basin
Amazon Basin
The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...
. Throughout this range various species occupy lakes, ponds and streams in either sunny savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
or shaded forest habitats, most often in shallow waters. The species of this genus are non-annual. Rivulus, together with the closely related genera Prorivulus (erected in 2004 and containing a single species) and Kryptolebias (erected in 2004, comprising species formerly assigned to Rivulus), contain the only species in the family Rivulidae to inhabit perennial aquatic biotopes.
Species
- Rivulus agilae Hoedeman, 1954
- Rivulus altivelis Huber, 1992
- Rivulus amanan Costa & Lazzarotto, 2008
- Rivulus amanapira Costa, 2004
- Rivulus amphoreus Huber, 1979
- Rivulus apiamici Costa, 1989
- Rivulus atratus Garman, 1895
- Rivulus auratus Schreitmüller, 1928
- Rivulus bahianus Huber, 1990
- Rivulus beniensis Myers, 1927
- Rivulus birkhahni Berkenkamp & Etzel, 1992
- Rivulus boehlkei Huber & Fels, 1985
- Rivulus bororo Costa, 2007
- Rivulus breviceps Eigenmann, 1909
- Rivulus brunneus Meek & Hildebrand, 1913
- Rivulus caurae Radda, 2004
- Rivulus christinae Huber, 1992
- Rivulus chucunaque Breder, 1925
- Rivulus cladophorus Huber, 1991
- Rivulus compressus Henn, 1916
- Rivulus corpulentus Thomerson & Taphorn, 1993
- Rivulus cryptocallus Seegers, 1980
- Rivulus cyanopterus Costa, 2005
- Rivulus cylindraceus Poey, 1860 - Green rivulus
- Rivulus dapazi Costa, 2005
- Rivulus decoratus Costa, 1989
- Rivulus deltaphilus Seegers, 1983
- Rivulus depressus Costa, 1991
- Rivulus derhami Fels & Huber, 1985
- Rivulus dibaphus Myers, 1927
- Rivulus egens Costa, 2005
- Rivulus elegans Steindachner, 1880
- Rivulus elongatus Fels & de Rham, 1981
- Rivulus erberi Berkenkamp, 1989
- Rivulus faucireticulatus Costa, 2007
- Rivulus formosensis Costa, 2008
- Rivulus frenatus Eigenmann, 1912
- Rivulus frommi Berkenkamp & Etzel, 1993
- Rivulus fuscolineatus Bussing, 1980
- Rivulus garciai de la Cruz & Dubitsky, 1976
- Rivulus geayi Vaillant, 1899
- Rivulus giarettai Costa, 2008
- Rivulus glaucus Bussing, 1980
- Rivulus gransabanae Lasso, Taphorn & Thomerson, 1992
- Rivulus haraldsiolii Berkenkamp, 1984
- Rivulus hartii (Boulenger, 1890) - Hart's rivulus
- Rivulus hildebrandi Myers, 1927
- Rivulus holmiae Eigenmann, 1909
- Rivulus igneus Huber, 1991
- Rivulus illuminatus Costa, 2007
- Rivulus immaculatus Thomerson, Nico & Taphorn, 1991
- Rivulus insulaepinorum de la Cruz & Dubitsky, 1976 - Isle of Pines rivulus
- Rivulus intermittens Fels & de Rham, 1981
- Rivulus iridescens Fels & de Rham, 1981
- Rivulus isthmensis Garman, 1895
- Rivulus jalapensis Costa, 2010
- Rivulus janeiroensis Costa, 1991
- Rivulus jucundus Huber, 1992
- Rivulus jurubatibensis Costa, 2008
- Rivulus kayabi Costa, 2007
- Rivulus kayapo Costa, 2006
- Rivulus kirovskyi Costa, 2004
- Rivulus kuelpmanni Berkenkamp & Etzel, 1993
- Rivulus lanceolatus Eigenmann, 1909
- Rivulus lazzarotoi Wilson, 2007
- Rivulus leucurus Fowler, 1944
- Rivulus limoncochae Hoedeman, 1962
- Rivulus litteratus Costa, 2005
- Rivulus luelingi Seegers, 1984
- Rivulus lungi Berkenkamp, 1984
- Rivulus lyricauda Thomerson, Berkenkamp & Taphorn, 1991
- Rivulus magdalenae Eigenmann & Henn, 1916 - Magdalena rivulus
- Rivulus mahdiaensis Suijker & Collier, 2006
- Rivulus marmoratus Poey, 1880 - Mangrove rivulus
- Rivulus mazaruni Myers, 1924
- Rivulus micropus (Steindachner, 1863)
- Rivulus modestus Costa, 1991
- Rivulus monikae Berkenkamp & Etzel, 1995
- Rivulus monticola Staeck & Schindler, 1997
- Rivulus montium Hildebrand, 1938
- Rivulus nicoi Thomerson & Taphorn, 1992
- Rivulus nudiventris Costa & Brasil, 1991
- Rivulus obscurus Garman, 1895
- Rivulus ophiomimus Huber, 1992
- Rivulus ornatus Garman, 1895
- Rivulus pacificus Huber, 1992
- Rivulus paracatuensis Costa, 2003
- Rivulus paresi Costa, 2007
- Rivulus parnaibensis Costa, 2003
- Rivulus peruanus (Regan, 1903)
- Rivulus pictus Costa, 1989
- Rivulus pinima Costa, 1989
- Rivulus planaltinus Costa & Brasil, 2008
- Rivulus punctatus Boulenger, 1895
- Rivulus rectocaudatus Fels & de Rham, 1981
- Rivulus roloffi Roloff, 1938 - Hispaniolan rivulus
- Rivulus romeri Costa, 2003
- Rivulus rossoi Costa, 2005
- Rivulus rubripunctatus Bussing, 1980
- Rivulus rubrolineatus Fels & de Rham, 1981
- Rivulus rutilicaudus Costa, 2005
- Rivulus santensis Köhler, 1906
- Rivulus sape Lasso-Alcalá, Taphorn, Lasso & León-Mata, 2006
- Rivulus scalaris Costa, 2005
- Rivulus siegfriedi Bussing, 1980
- Rivulus simplicis Costa, 2004
- Rivulus speciosus Fels & de Rham, 1981
- Rivulus stagnatus Eigenmann, 1909
- Rivulus strigatus Regan, 1912 - Herringbone rivulus
- Rivulus taeniatus Fowler, 1945
- Rivulus tecminae Thomerson, Nico & Taphorn, 1992
- Rivulus tenuis (Meek, 1904) - Dogtooth rivulus
- Rivulus tessellatus Huber, 1992
- Rivulus torrenticola Vermeulen & Isbrücker, 2000
- Rivulus uakti Costa, 2004
- Rivulus uatuman Costa, 2004
- Rivulus uroflammeus Bussing, 1980
- Rivulus urophthalmus Günther, 1866
- Rivulus villwocki Berkenkamp & Etzel, 1997
- Rivulus violaceus Costa, 1991
- Rivulus vittatus Costa, 1989
- Rivulus waimacui Eigenmann, 1909
- Rivulus wassmanni Berkenkamp & Etzel, 1999
- Rivulus weberi Huber, 1992
- Rivulus xanthonotus Ahl, 1926
- Rivulus xiphidius Huber, 1979
- Rivulus zygonectes Myers, 1927