May 2025
Barred Tail Pearlfish, Notholebias minimus
Image © Yuri Borba
The Barred Tail Pearlfish, Notholebias minimus, a threatened species of South American Killifish (Rivulidae), inhabits temporary wetlands in the Atlantic Forest biome, in the coastal plains of the southeastern region of Brazil, in the State of Rio de Janeiro. Its distribution is limited to areas west of Guanabara Bay, ranging from the Jacarepaguá Lagoon System to the Guarda River basin, in the municipalities of Rio de Janeiro, Seropédica, and Itaguaí. The species, like most annual Killifish, has a restricted geographic distribution, low dispersal capacity, small body size, rapid growth, pronounced sexual dimorphism, and a life cycle synchronized with the rainy season. During the dry season, the eggs in the substrate remain in embryonic diapause, awaiting the next rainy season to initiate the life cycle at the onset of the rains. The species is assessed as Endangered by the IUCN Red List of Threatened Species™. Agricultural expansion and unplanned urban sprawl are the primary causes of significant population declines across the species’ distribution, due to habitat fragmentation, landfilling, cattle grazing, pesticide use, and draining of wetlands. However, countermeasures are being taken to conserve this species. It is included in the Brazilian National Action Plan for the protection and development of strategies for the conservation of endangered species of the Rivulidae family, known as the “PAN Rivulídeos” of the Chico Mendes Institute for Biodiversity Conservation (ICMBio), linked to the Ministry of the Environment.
Nominated by FFSG Members Carlos H. P. Luz, and Paulo A. Buckup, Brazil