Type species: Anablepsoides atratus

Untergattung Huber 1992 / Gattung Costa 2011 / Untergattung Huber 2012/ Gattung Costa 2013, Valdesalici 2016


Owiyeye (subgenus of Rivulus) Synonym of Laimosemion

Phylogenetic position and taxonomic status of Anablepsoides, Atlantirivulus, Cynodonichthys, Laimosemion and Melanorivulus (Cyprinodontiformes: Rivulidae)

Wilson J. E. M. Costa 2011

A maximum parsimony analysis of a combined set of mitochondrial and morphological data available in the literature for 33 rivuline taxa and three outgroups confirms Rivulus as a paraphyletic assemblage. In order to adjust a generic classification to our present phylogenetic knowledge on rivuline relationships, the following taxonomic changes are proposed: Rivulus, restricted to two species endemic to Cuba, is hypothesized to be the most basal rivuline lineage, distinguished from all other non-annual rivulines by having all hypurals fused into a single plate, neural prezygapophysis of caudal vertebrae rudimentary, fourth ceratobranchial teeth absent, about 50 % of the anterior portion of the caudal fin covered by scales, four neuromasts on the anterior supraorbital series, and a black round spot with white margin on the dorsoposterior portion of the caudal peduncle in females; Anablepsoides, Atlantirivulus, Laimosemion, Melanorivulus and Cynodonichthys, previously classified as subgenera of Rivulus, are considered as valid genera; Laimosemion, including 24 species from northern South America, constitutes the sister group to a clade comprising Melanorivulus, Cynodonichthys, Anablepsoides, Atlantirivulus, and all annual rivuline genera, which is supported by a well-developed dorsal process of the urohyal and an expanded lateral articular facet of the first hypobranchial; Melanorivulus, comprising 34 species from central and northeastern South America, Cynodonichthys with 27 species from Central America and Trans-Andean South America, Anablepsoides with 42 species from northern and northeastern South America and Smaller Antilles, and Atlantirivulus, with 11 species endemic to the eastern Brazilian coastal plains are diagnosed by combinations of morphological characters, including osteology, cephalic laterosensory system and colour patterns.


Huber, J.H., Reappraisal of the Phylogeny of Rivulus and its Allied focused on External Characters. Killi‐ Data Series 2012, 9‐25, 3 figs., 2 tabs.

Abstract: In the present study all known to date phylogenetic lineages encompassing the genus Rivulus in the large sense and its relatives, 44 in total, are benchmarked against a very long list of external characters involving global and detailed morphology of each, plus some characters related to biology, behavior and ecology, plus a few characters concerning the vertebrae counts and their structure. The parsimony analysis for these 144 characters results in 3 trees only, very much in line with the global stability of major lineages and the consensus tree produces bootstrap values that are much higher than previously released studies with morphological and osteological characters. In the resulting tree, outside Kryptolebias already separated in 2004, the genus Rivulus in the large sense is shown as a monophyletic assemblage like in the molecular study by Murphy, Thomerson & Collier (1999), with annual and non‐ annual species separated, but unlike Costa (2011) who used both morpho‐osteological and molecular combined characters. Apart from the coherence of the genus Rivulus in a large sense, the analysis newly suggests the primitive position of Millerichthys, the monophyly of major annual subclades, and the phylogenetic relationship of a clade of 3 subgenera of Rivulus, namely Prorivulus, Atlantirivulus, Melanorivulus in line with a previous palaeo‐bridge hypothesis and the minor osteological diagnostic characters that were forwarded for these 3 taxa should be deepened and re‐evaluated. Two other subunits of Rivulus, namely Anablepsoides and Oditichthys, are atypically placed in the tree, but their 2 type species were not studied by Costa (2011) and that too would need re‐evaluation. Finally several phylogenetic lineages belonging to the huge ‐and very poorly known‐ Amazon basin ends up in an unstable position and more material and characters are thought necessary for further research of this very difficult group of fish.


Laimosemion (28 Arten)



Laimosemion agilae (Hoedeman, 1954)

Laimosemion agilae "Montagne de Matoury FG 2011" 


Laimosemion altivelis (Huber, 1992)

Review of Rivulus. Ecobiogeography - Relationships. Cybium Suppl., Société Française d'Ichtyologie Publ.: 93, fig. 29a.

Type locality: Raudal Alto, approx. 90 km northeast of mouth of Papunava river, Inirida river basin, Guainia Dept., Amazonian Colombia.


Laimosemion amanapira (W. J. E. M. Costa, 2004)

Rivulus uakti sp. n. and R. amanapira sp. n. (Teleostei: Cyprinodontiformes: Rivulidae): two new species from the upper Rio Negro, Brazilian Amazon. Zootaxa, 465: 7, figs. 4-5.

Type locality: São Gabriel da Cachoeira, near igarapé Palestina, Airport road, upper rio Negro drainage, rio Amazonas basin, Amazonas state, (northern) Brasil, altitude 110 m.

Laimosemion breviceps (C. H. Eigenmann, 1909)

Reports on the Expedition to British Guiana of the Indiana University and Carnegie Museum, 1908. Report No. 1. Some new Genera and Species of Fishes from British Guiana. Ann. Carnegie Mus., 6 (1): 49.

Type locality: Shrimp creek (vernacular: Orimetuk), near Kaieteur, (British) Guiana.

Laimosemion cladophorus (Huber, 1991)

Revue des Espèces de Rivulus de Guyane française, avec Descriptions de R. cladophorus n.sp. et de R. igneus n. sp. Rev. fr. Aquariol. Herpétol., 18, (3): 71, fig. 6.

Type locality: Saint Elie Station, along the Mosaïque sector, interior Guyane.

Laimosemion dibaphus (G. S. Myers, 1927)

An Analysis of the Genera of neotropical Killifishes allied to Rivulus. Ann. & Mag. Nat. Hist., 9 (19): 121.

Type locality: Igarapé do Ajamuri (a beach of lago Grande, at mouth of rio Maicuru, a little east of Santarem, on north of bank of Amazon river, subseq.), Lower Amazon, Brasil.


Laimosemion frenatus (C. H. Eigenmann, 1912)

The Freshwater Fishes of British Guiana, including a Study of the ecological Grouping of Species and the Relation of the Fauna of the Plateau to that of the Lowlands. Mem. Carnegie Mus., 5: 453, 455.

Type locality: Essequibo river at Gluck fluvial island, just upstream of Rockstone, (British Guiana) Guyana.


Laimosemion geayi (Vaillant, 1899)

An Analysis of the Genera of neotropical Killifishes allied to Rivulus. Ann. & Mag. Nat. Hist., 9 (19): 121.

Type locality: Igarapé do Ajamuri (a beach of lago Grande, at mouth of rio Maicuru, a little east of Santarem, on north of bank of Amazon river, subseq.), Lower Amazon, Brasil.

Laimosemion gransabanae (Lasso A., Taphorn & Thomerson, 1992)

Rivulus gransabanae, a New species of Killifish from Venezuela (Cyprinodontiforms, Rivulidae). Ichthyol. ExpIor. Freshwaters, 2 (4): 298, figs. 2-3.

Type locality: quebrada (creek) Pacheco, between Tuperere river II and San Ignacio Yuruaní, on the road Kama-San Ignacio Yuruani, Gran Sabana, Estado Bolivar, Venezuela.


Laimosemion jauaperi W. J. E. M. Costa & Bragança, 2013 

A new miniature killifish of the genus Laimosemion, subgenus Owiyeye, from the Negro river drainage, Brazilian Amazon (Cyprinodontiformes: Rivulidae). Ichthyological Exploration of Freshwaters, 24 (1): 93-96.

Laimosemion jauaperi, new species, from the Jauaperi river drainage, central Brazilian Amazon, is described. It was found in a shallow, black-water pool adjacent to a stream within dense forest. Laimosemion jauaperi differs from all other rivulines by possessing four pelvic-fin rays in the female (vs. 5-9), four branchiostegal rays (vs. 5-6) and the presence of a distinctive anterior white zone on the anal fin (vs. absence). Laimosemion jauaperi is hypothesized to be closely related to Laimosemion uatuman from the Uatumã river drainage by both, uniquely among rivulines, sharing the presence of caudal fin dark coloured with a contrasting distal white band in males.


Laimosemion kirovskyi (W. J. E. M. Costa, 2004)

Rivulus kirovskyi, a new killifish from the central Amazon, Brazil (Cyprinodontiformes: Rivulidae). Neotropical Ichthyology, 2 (1) : 10, fig. 1.

Type locality: Reserva Ducke, near igarapé Acara, lower rio Negro drainage, rio Amazonas basin, Manaus county, Amazonas state, (northern) Brasil. 


Laimosemion leticia Valdesalici, 2016 [3]

Laimosemion leticia (Teleostei: Cyprinodontiformes: Rivulidae), a new species from the upper Rio Amazonas, Southern Colombia. Zootaxa, 4085 (2): 279–284. 

 Laimosemion leticia is described from the Rio Tacana drainage, upper Rio Amazonas basin, Southern Colombia. The new species was found in a shallow swamp within a tropical rainforest in the vicinity of Leticia, capital of the department of Amazonas and southernmost municipality of Colombia. This miniature species is considered to be a member of the Owiyeye subgenus, which is diagnosed by a unique frontal squamation. Laimosemion leticia can be distinguished from all other species of the genus by the unique colour pattern on the unpaired fins. The new species appears related to L. jauaperi, L. uatuman and L. ubim due to the similar flank colour pattern in males, but is easy distinguished by coloration of the unpaired fins and morphological characters.


Laimosemion lyricauda (Thomerson, Berkenkamp & Taphorn, 1991)

Rivulus lyricauda, a new Species from the Guyana Shield in eastern Venezuela (Cyprinodontiforms, Rivulidae). Ichthyol. ExpIor. Freshwaters, 1 (4) (1990): 290, figs. 1-3.

Type locality: Campamiento Canaima, tributary to río Carrao, río Caroni basin, Estado Bolivar, (interior) Venezuela. 


Laimosemion mabura Valdesalici & García-Gil, 2015 

Laimosemion mabura, a new killifish from the Essequibo River drainage, Guyana (Cyprinodontiformes: Rivulidae). aqua, International Journal of Ichthyology, 21 (4): 166-171.

Laimosemion mabura, new species, is described from a small stream belonging to the Essequibo River drainage, central Guyana. Males of Laimosemion mabura are similar to those of L. dibaphus, to which the new species may be closely related, in possessing bluish black pigmentation on the caudal peduncle, but differ in certain morphological characters and elements of colour pattern. The new species belongs to the L. geayi species group, and is distinguished from other members of this assemblage by male colour pattern.

Laimosemion mabura



Laimosemion mahdiaensis (Suijker & Collier, 2006)

Rivulus mahdiaensis, a new killifish from central Guyana (Cyprinodontiformes: Rivulidae). Zootaxa 1246:1-13. 

Rivulus mahdiaensis, new species, was found in a small creek, a tributary of the Potaro River, near Mahdia, central Guyana. Males differ from all other species of the genus Rivulus by possessing elongate anal and dorsal fins, and an extremely large and lyre-shaped caudal fin with long extensions. Females differ from other species of the genus, except for three closely related species, by the presence of a narrow, dark longitudinal band on the sides. R. mahdiaensis possesses a unique karyotype (2n=38) among members of this group. Comparison of mitochondrial DNA sequences place this species as a member of a monophyletic clade which includes other small species from the Guyana shield and adjacent areas of northeastern South America.


Laimosemion nicoi (Thomerson & Taphorn, 1992)

Two new annual Killifishes from Amazonas Territory, Venezuela (Cyprinodontiformes: Rivulidae). Ichthyol. ExpIor. Freshwaters, 3 (4): 380, fig. 4.

Type locality: ca. 500 m from right bank of río Ventuari, Orinoco drainage, Venezuela.


Laimosemion paryagi Vermeulen, Suijker & Collier, 2012 (Paryag's killifish) 

Laimosemion paryagi (Cyprinodontiformes: Aplocheiloidei: Rivulidae), a new species from the upper Mazaruni river drainage of Western Guyana. aqua, International Journal of Ichthyology, 18 (4): 181-190.

 Laimosemion paryagi, new species, is described from the upper Mazaruni river system, a tributary of the Essequibo River. It is a member of the Laimosemion breviceps group former known as the Rivulus breviceps group, and shares a robust body and deep caudal peduncle with Laimosemion breviceps (Eigenmann, 1909) and Laimosemion lyricauda (Thomerson et al., 1991) and to a lesser degree with L. gransabanae (Lasso et al., 1992) and Laimosemion torrenticola (Vermeulen & Isbrücker, 2000). These species are all endemic to the Guiana Highlands in western Guyana and the neighbouring Gran Sabana in Eastern Venezuela. It is distinguished from other species in the L. breviceps group by morphology and its remarkable male color pattern of red blotches on a turquoise ground color on the flanks and in the unpaired fins and having a rounded caudal fin as opposed to one having extension or being spade shaped. Analysis of mitochondrial DNA sequence reveals that it is genetically distinct from all other members of this group and that inhabitants of the Guyana highlands diverged from each other early in the history of the genus, commensurate with the geological age of the Guiana Shield.


Laimosemion rectocaudatus (Fels & de Rham, 1981)

Récentes Collections de Rivulus (Cyprinodontidés) au Pérou, avec Description de six nouvelles Espèces. 1. Rev. fr. Aquariol. Herpétol., 8 (3): 66, Figs 1, 16, 19, 20.

Type locality: Vivero Forestal El Varillal, 34 km from Iquitos on the Iquitos-Nauta road, Peru.


Laimosemion romeri (W. J. E. M. Costa, 2003)

A new miniature rivuline fish from the upper Negro River basin, northern Brazil (Teleostei, Cypridontiformes, Rivulidae). Arquivos do Museu Nacional, Rio de Janeiro, 61 (3): 176, figs. 1-3.

Type locality: tributary to Igarapé Iauiari, which is a tributary of Uaupés river, itself a tributary of Negro river, Amazonian basin, northern Brasil.


Laimosemion sape (Lasso-Alcalá, Taphorn, Lasso A. & León-Mata, 2006)

Rivulus sape, a new species of killifish (Cyprinodontiformes: Rivulidae) from the Paragua River system, Caroní River drainage, Guyana Shield, Venezuela. Zootaxa 1275:21-29.

A new species, Rivulus sape, is described from two tributaries of the upper Paragua River, Caroní River drainage, of the Guyana Shield in Venezuela. It is a small (all specimens examined less than 50 mm SL), apparently non-annual species that is distinguished from congeners in having the dorsal, anal, and pelvic fins short; adult males with a truncate caudal fin with the upper and lower borders black; and an iridescent blue, ovate spot on sides of the body above the pectoral fins. Neither adults nor juveniles have an ocellus at the dorsal junction of the caudal peduncle and caudal fin. Only one contact organ per scale on some scales along the sides of the body was observed.


Laimosemion staecki (I. Schindler & Valdesalici, 2011)

Rivulus staecki, a new killifish (Teleostei: Cyprinodontiformes: Rivulidae) from the upper Rio Negro drainage in southern Venezuela. Vertebr. Zool. 61(1):109-114.

Rivulus staecki, a new species of the subgenus Owiyeye, is described from the upper Rio Negro drainage in southern Venezuela (Estado Amazonas). It differs from the other species of the subgenus by a unique combination of character states: a truncate caudal fi n, elongated pelvic fi ns in males, presence of a ‘rivulus spot’ in both sexes and 35 – 38 scales in the longitudinal series.

Laimosemion staecki


Laimosemion strigatus (Regan, 1912)

A Revision of the Poeciliid Fishes of the Genera Rivulus, Pterolebias, and Cynolebias. Ann. & Mag. Nat. Hist., 8 (10): 502.

Type locality: Amazon river (Rio da Prata, Para State, subseq.), Brasil.


Laimosemion tecminae (Thomerson, Nico & Taphorn, 1992)

Rivulus tecminae, a New Killifish from Amazonas Territory Venezuela (Cyprinodontiforms, Rivulidae). Ichthyol. ExpIor. Freshwaters, 2 (4): 290, figs. 1-3.

Type locality: ca. 500 m from left bank, río Guayapo, about 83 km above confluence with rio Sipapo, río Orinoco basin, Amazonas Federal Territory, Venezuela.

Laimosemion torrenticola (Vermeulen & Isbrücker, 2000)

Rivulus torrenticola n. sp. (Actinopterygii: Cyprinodontiformes: Rivulidae), a new Killifish from Highlands in the Guyana shield. Beaufortia, 50 (10), December: 186, figs. 1-2.

Type locality: near Kamarang village, creek at right bank Kamarang river, half a mile (0.8 km) from landing of general store of Paul James, Guiana (southern Guyana).


Laimosemion uakti (W. J. E. M. Costa, 2004)

Rivulus uakti sp. n. and R. amanapira sp. n. (Teleostei: Cyprinodontiformes: Rivulidae): two new species from the upper Rio Negro, Brazilian Amazon. Zootaxa, 465: 2, figs. 1-2.

Type locality: São Gabriel da Cachoeira, near igarapé Iá, PK 9.4 of the road São Gabriel da Cachoeira to Cucuí, upper rio Negro drainage, rio Amazonas basin, Amazonas state, (northern) Brasil, altitude 99 m.

Laimosemion uatuman (W. J. E. M. Costa, 2004)

Rivulus uatuman sp. n. (Teleostei: Cyprinodontiformes: Rivulidae): a new miniature killifish from the central Brazilian Amazon. Zootaxa, 696: 2, figs. 1-2.

Type locality: Balbina, close to Rio Uatumã, rio Amazonas basin, Estado do Amazonas, (northern) Brasil, altitude 43 m.


Laimosemion ubim W. J. E. M. Costa & Lazzarotto, 2014 

Laimosemion ubim, a new miniature killifish from the Brazilian Amazon (Teleostei: Rivulidae). Ichthyological Exploration of Freshwaters, 24 (4): 371-389.

Laimosemion ubim, new species, is described from a small stream tributary of Lago Amanã system, Central Amazon, northern Brazil, based on external and internal anatomical morphological characters. It is considered closely related to other species of Laimosemion, subgenus Owiyeye, from the same region. It is distinguished from all other rivulids by having double-branched epipleural ribs, a condition never found among cyprinodontiforms, and from all its congeners by having hypertrophied teeth on the anterior portion of the outer row of the premaxilla and dentary in males. It reaches a maximum adult size of about 18 mm SL and exhibits several reductive characters, as expected for a miniature species, including a notable reductive character state – four branchiostegal rays.


Laimosemion xiphidius (Huber, 1979)

A propos de quatre nouvelles Collections de Rivulus des Guyanes, avec Description de Rivulus xiphidius n. sp. et Rivulus amphoreus n. sp. Rev. fr. Aquariol. Herpétol., 6: 66, fig. 3.

Type locality: upstream of Saint-Georges, in the back of Maripa falls, a few hundred meters from Oyapock, near Brasilian border, Guyane française.


Laimosemion xiphidius "FBS 1995-2"