The genus Austrolebias was described by Dr. Wilson Costa 1998, with which he split the long-established Genus Cynolebias, described by Steindachner in 1876, into 3 genera. One is Cynolebias, the second is Megalebias, but in 2006 he synonimized Megalebias to Austrolebias.

Genus Austrolebias Costa, 1998

Type species: Cynolebias bellottii Steindachner, 1881, type by original designation.

Included species: Austrolebias melanoorus (Amato, 1986), Austrolebias vandenbergi (Huber, 1995), Austrolebias univentripinnis Costa & Cheffe, 2005, Austrolebias queguay Serra & Loureiro, 2018, Austrolebias bellottii (Steindachner, 1881), Austrolebias accorsii Nielsen & Pillet, 2015, Austrolebias ephemerus Volcan & Severo-Neto, 2019 and Austrolebias ayoreode Drawert & Ergueta 2024

Diagnosis:

Genus Austrolebias can be distinguished from other genera within the Austrolebias genus group by the following unique combination of characters: (1) urogenital papillae attached to anal fin (except in Austrolebias vandenbergi and Austrolebias accorsii); (2) anteromedial anal fin rays longer than the rest in females, resulting in a nearly triangular fin shape; (3) males pectoral fins hyaline, with black margin and iridescent submargin (except Austrolebias melanoorus, which has only the black margin); (4) pelvic bones overlapping; (5) absence of regular, well-defined vertical dark grey bars only on anterior portion of flank (anterior to the anal fin origin); (6) absence of dark grey pigmentation in cephalic neuromasts concentrated in parietal series; and (7) in females, absence of black spots on posterior flank and vertically aligned in the peduncle.

Differential diagnosis:

The genus Austrolebias can be distinguished from all other genera of the Austrolebias genus group by having < 40 scales in the longitudinal series (vs. > 40 scales in Titanolebias); by the presence of scales in the preopercular region (vs. absent in Gymnolebias); by the basal and medial region of pectoral fins being hyaline in adult males (vs. non-hyaline in Argolebias, Acantholebias, Matilebias, Megalebias, Acrolebias and Cypholebias); anteromedial anal fin rays longer than the rest of the fin rays in females, resulting in a nearly triangular fin shape (vs. rounded anal fin in Amatolebias); urogenital papillae attached to male anal fin, if not, presence of contact organs on anal fin (vs. urogenital papillae not attached to

male anal fin in all Garcialebias species except Garcialebias cheffei Volcan et al., 2021, which differs from Austrolebias by the lack of contact organs on the anal fin).

Behavior:

These typically seasonal fishes spawn during there entire adult lifespan diving in the soft bottom layer. The parents die when waters are evaporating or even before that event as they do not live very long. The rain will bring the buried eggs to hatch and the fry, that will grow very rapidly is able to produce the first eggs after 6 weeks of age if food is abundant available.

Literature:

Steindachner, F. 1876. Ichthyologische Beitrage (V). Sitz. Akad. Wiss. Wien mathem.-naturwiss. Klasse Abt.1, 74: 172.

Costa, W.J.E.M. 1998. Phylogeny and Classification of Rivulidae revisited: Origin and Evolution of Annualism and Miniaturization in Rivulid Fishes (Cyprinodontiformes: Aplocheilidei). J. Comp. Biol., 3 (1),

Costa, W.J.E.M. 2006c. The South American annual Killifish Genus Austrolebias Teleostei: Cyprinodontiformes: Rivulidae): phylogenetic Relationships, descriptive Morphology and taxonomic Revision. Zootaxa,: 1-162, 52 figs., 9 tabs.

Loureiro M., R. de Sá, S. W. Serra, F. Alonso, L. E. Krause Lanés, M. Vieira Volcan, P. Calvino, D. B. Nielsen, A. Duarte and G. Garcia. 2018.  Review of the family Rivulidae (Cyprinodontiformes, Aplocheiloidei) and a molecular and morphological phylogeny of the annual fish genus Austrolebias Costa 1998. Neotropical Ichthyology, 16(3)

Alonso F., G.E. Terán, W.S. Serra Alanís, P. Calviño, M.M. Montes, I.D. Carcía, J.A. Barneche, A. Almirón, L. Ciotek, P. Giorgis, J. Casciotta, 2023. From the mud to the tree: phylogeny of Austrolebias killifishes, new generic structure and description of a new species (Cyprinodontiformes: Rivulidae) Zool. Journ. of the Linnean Society, XX, 1-30, Fig. 15, Tab. 2.

See: Austrolebias group introduction page for comment.