Argolebias (Costa 2008)

Argolebias 𝑎𝑑𝑟𝑖𝑎𝑛𝑎𝑒 (Felipe Alonso et al., 2024)

Argolebias guarani, (Felipe Alonso et al., 2023)

Argolebias nigripinnis Regan 1912. (Foto)

Argolebias paranaensis (Costa, 2006)

Argolebias adrianae, new species  ( Felipe Alonso 2024)

Expect the unexpected: a new species of killifish from a highly stochastic temporary wetland near Iguazú Falls (Cyprinodontiformes: Rivulidae) Felipe Alonso 2024

Canadian Journal of Zoology, 102 (3): 298-314


We describe Argolebias adrianae, a new species of killifish from a small temporary wetland in the Paraná Forest ecoregion with no regular or predictable temporal pattern of water availability. This habitat is in the Lower Iguazú River Basin, known for its high fish endemism, but until now, only two species of Rivulidae were reported from it, but from the Araucarian Forest ecoregion. The genus Argolebias was previously only known from the lower portions of the Paraguay, Paraná, and Uruguay basins and middle Paraná. The new species is distinguished from all congeners by its unique coloration, which includes a conspicuously dark grey anterior third portion of the dorsal fin and the absence of iridescent spots on the basal half of the pectoral fin in live adult males, as well as dark grey spots on the anterocentral portion of the flanks of females. Our phylogenetic analysis shows A. adrianae to be closely related to Argolebias guarani from the adjacent Middle Paraná basin. We also provide data on the ecology, ontogeny of coloration, and chorion ornamentation of this species. Our findings have important implications for understanding the biogeography, ecology, and evolution of mechanisms that enable organisms to thrive in highly stochastic environments like this one.


Argolebias guarani Alonso, Teran, Serra, Calviño, Montes, García, Barneche, Almiron, Ciotek, Giorgis & Casciotta, 2023. From the mud to the tree: phylogeny of Austrolebias killifishes, new generic structure and description of a new species (Cyprinodontiformes: Rivulidae)

Zoological Journal of the Linnean Society: 30 pp. 15 figs.


Killifishes (Cyprinodontiformes) are a group of fish that include a high proportion of small-bodied species living in seasonal aquatic habitats, with narrow geographical distributions and high human impact. They are among the most vulnerable vertebrates in the Neotropical region, with nearly half of the species in threat categories. Herein, we propose a new phylogenetic hypothesis of the Rivulidae genus Austrolebias, based on 10 genes (six nuclear and four mitochondrial) and 191 morphological characters, including 90% of the total valid species of this genus. An updated definition and diagnosis of the existing subgenera of Austrolebias is provided, and these are erected to genera. Also, four new genera are erected to accommodate the taxonomy of the group to the current phylogenetic hypothesis. Additionally, we describe Argolebias guarani sp. nov., from a seasonal pond in the Middle Paraná River basin, which is diagnosed by a unique colour pattern. This addition reinforces this area as a biodiversity hotspot of endemicity and highlights the importance of this region for conservation. Data on the ontogenetic changes in colour pattern, chorion ornamentation of the egg and ecology of this species are also provided.


Argolebias nigripinnis (Regan, 1912)

A Revision of the Poeciliid Fishes of the Genera Rivulus, Pterolebias, and Cynolebias. Ann. & Mag. Nat. Hist., 8 (10): 508.

Type locality: Río de la Plata, Argentina.

Argolebias nigripinnis

Argolebias nigripinnis "Ceibas MSL 1991/2"

Argolebias nigripinnisbias "La Peregrina"

Argolebias nigripinnis "Rosario del Tala"


Austrolebias paranaensis (Costa, 2006)

The South American annual Killifish Genus Austrolebias (Teleostei: Cyprinodontiformes: Rivulidae): phylogenetic Relationships, descriptive Morphology and Taxonomic Revision. Zootaxa, (1213): 81, fig. 32.

Type locality: 2 km east of Ayolas, Misiones, Paraguay.