Ândrio Cardozo Gonçalves

Threatened fishes of the world: Austrolebias nigrofasciatus Costa and Cheffe 2001 (Cyprinodontiformes: Rivulidae)

Common names: Annual fish, killifish. Conservation status: “Endangered” (Fontana et al. 2003, MMA 2004). Identification: 21–26 anal-fin rays in males and 18–23 in females, 19–22 caudal-fin rays, 27–29 vertebrae. Illustration by Felipe Ribas. Coloration: Males: body’s sides metallic blue, with 6–12 dark brown to black bars. Females: body’s sides light yellowish brown, with vertical rows of elongate gray spots, sometimes forming gray bars (Costa and Cheffe 2001; Costa 2006). Distribution: Endemic to river drainages associated with the margin of São Gonçalo channel, Patos-Mirim lagoon system, Rio Grande do Sul, southern Brazil. Abundance: Relatively abundant in its restricted area of occurrence, however there is not estimation on the size of population. Habitat and ecology: Inhabits seasonal wetlands that are formed during the rainy seasons in southern Brazil and it is registered syntopic occurrence in two other species of annual fish: Cynopoecilus melanotaenia and Austrolebias wolterstorffi. Reproduction: Sexual maturity reached about a month after the hatching and presents average fertility of around 30 eggs per week (Volcan 2009). Threats: The drainage and the landfill of areas of floodplain for urban construction in restricted area of distribution of the species and the cultivation of rice in adjacent areas to the São Gonçalo channel are the main threats. Conservation action: It was theoretically protected in its type-locality, in the Pontal da Barra swamp, whose area was established as a Private Natural Heritage Reserve, but the grounding of the property for construction and negligence of local authorities with this fact, threaten the population type of the specie. Conservation recommendations: Establish some form of legal protection in the area where the species occurs, inclusion of species in genus Austrolebias in listings of IUCN and recovery and monitoring of its habitat. Environ Biol Fish (2009) 86:443–444 DOI 10.1007/s10641-009-9544-x

Threatened fishes of the world: Austrolebias univentripinnis Costa and Cheffe 2005 (Cyprinodontiformes: Rivulidae)

Common names: Annual fish, killifish. Conservation status: None. Identification: Urogenital papilla completely attached to anal fin in males, pelvic fins 75 to 90% fused. Largest male registered 35.6 mm SL and largest female 32.2 mm SL (Illustration by Felipe Ribas). Coloration: Lateral body of males with 11–18 vertical rows of brilliant blue-green pigmentation on a dark greenish gray background. Lateral body of females with elongated bars on a faint yellow-brown background (Costa and Cheffe 2005). Distribution: Endemic to Jaguarao River basin, Patos-Mirim Lagoon system, Rio Grande do Sul, Brazil. Abundance: Population estimates not available. Habitat and ecology: Inhabit shallow temporary pools that are formed generally between June to September, in the winter months, during the rainy season. Pools generally are small in surface area (<1,000 m) with maximum depth of 50 cm and high density of aquatic macrophytes. The pH was 6.6–6.8 and the water was whitish. Reproduction: Unknown; likely similar to congenera, which mature within two months after hatching and reproduce throughout his life (Errea and Danulat 2001). Threats: Greatest threat is caused by drainage and changes in physical structure and the hydrological cycle of wetlands due to rice cultivation in floodplains of the Jaguarao River and its small tributaries. The loss of habitat caused by urban progress in the city of Jaguarao and the cattle presence in all sampling sites of the species are also threats to populations of A. univentripinnis (Lanes and Cheffe 2006). Conservation action: None taken. Conservation recommendations: Establish some form of legal protection, as small conservation units, in areas of occurrence of the species; realization of studies regarding the biology and ecology; inhibit the illegal draining and use of wetlands for rice cultivation and urban construction; include it in lists of species of fauna threatened with extinction and recovery and monitoring of its habitat. Environ Biol Fish (2010) 87:319–320 DOI 10.1007/s10641-010-9605-1

The fish fauna of the Corrientes stream basin, Patos lagoon system, state of Rio Grande do Sul, southern Brazil

The fish sampled in this study were captured in seasonal collections samplings, conducted between May 2006 and February 2007 in 15 stretches of the Corrientes stream basin, Patos lagoon system, Rio Grande do Sul state, Brazil. A total of 8088 specimens were collected, belonging to nine orders, 24 families and 68 species. In general, the ichthyofauna in this basin has the same pattern recognized for Neotropical rivers with predominance of Characiformes and Siluriformes orders and a high representative of the Characidae and Loricariidae families.

Pisces, Cyprinodontiformes, Rivulidae, Austrolebias periodicus (Costa, 1999): Distribution extension in state of Rio Grande do Sul, southern Brazil

The present note extends the distribution of annual killifish Austrolebias periodicus , a endangered species, endemic of the Pampas region, in Ibicui River basin, state of Rio Grande do Sul, southern Brazil. This information is needed to develop conservation strategies for this species and its habitat, which are at high risk due to the expansion of rice production and exotic forests in southern Brazil.

A new annual fish of the genus Austrolebias (Cyprinodontiformes: Rivulidae) from Rio Camaquã basin, Laguna dos Patos system, Brazilian Pampa

A new species of Austrolebias is described from the middle course of the Rio Camaquã, Laguna dos Patos system, Rio Grande do Sul, Brazil. The new species belongs to the Austrolebias alexandri species group, which is distinguished from the remaining congeners by the presence of a dark gray pectoral fin with bright blue iridescence in males. The new species is distinguished from all remaining species of the A. alexandri species group by the following combination of characters: presence of well-defined bright blue bars on the flank in males, shorter caudal fin length in males and females, contact organs in the first three rays of the pectoral fin in males, one to two post-optic neuromasts (rarely three), basihyal width of 50% of the length, and basihyal cartilage about 50-60% of the basihyal length. The recognition of this new species belonging to the A. alexandri group endemic of the middle course of Rio Camaquã and the recent discovery of Austrolebias bagual in the same general region reinforces the claim of the middle Rio Camaquã basin as an area of endemism for annual fishes and as such, a priority area for conservation in southern Brazil.

Body size and population dynamics of annual fishes from temporary wetlands in Southern Brazil

Annual fishes live exclusively in temporary wetlands where several species coexist. Understanding how annual fishes cohabit in small and isolated pools is still a challenge. In this study, we aimed to examine the prediction that annual fish assemblages in temporary pools in Southern Brazil are structured by temporal differences in body size, specific growth rate and density. Two–three fish species coexisted in each pool. The most abundant and frequent species were Cynopoecilus melanotaenia and Austrolebias nigrofasciatus, while A. wolterstorffi was less abundant and rare. The species differed significantly in body size throughout the flooding phase and showed similar growth patterns, with higher specific growth rates in the first months of flooding and a reduction in growth rate thereafter. The monthly average densities of A. nigrofasciatus and C. melanotaenia did not differ over time, but they were higher than values observed for A. wolterstorffi. Our results provide evidence for hatching synchrony, similar specific growth rates and densities among the most abundant species and differences in body sizes among all species that are more evident after adulthood, suggesting that differences in body size mediate the coexistence of annual fishes in temporary pools.

First record of blackfin pearlfish Austrolebias nigripinnis (Regan, 1912 (Cyprinodontiformes, Cynolebiidae) from Brazil

Austrolebias Costa is a genus of annual fish inhabiting temporary wetlands in the Chaco-Pampasic region of southern Brazil, Uruguay, Paraguay, Bolivia and Argentina (Costa, 2006, Nielsen & Pillet, 2015, Alonso et al., 2016). Currently, about 45 species of Austrolebias are known (Costa, 2006, Volcan et al., 2014, Nielsen & Pillet, 2015), and of these, 24 occur in Rio Grande do Sul, the southernmost state of Brazil, distributed across the Rio Uruguay basin and the Patos-Mirim lagoon system and adjacent coastal areas (Volcan et al., 2015).