Molecular biogeography of the Neotropical fish Hoplias malabaricus (Erythrinidae:Characiformes) in the Iguaçu, Tibagi, and Paraná Rivers

Abstract

Hoplias malabaricus, the common trahira, extended its range into the Iguaçu River sometime in the last decades. To determine levels of genetic differentiation in neighboring basins of this nominal taxon, as well as to unveil the source of the invading population, we analyzed patterns of similarity of RAPD-PCR genomic markers of samples from Paraná, Iguaçu and Tibagi Rivers. The high genetic diversity of samples from the Paraná and Tibagi Rivers suggested strong population structuring or even the occurrence of undescribed species. All alleles of the sample from the headwaters of Tibagi River were present in the sample from the Iguaçu River, which suggests that the former population or another population with similar genetic makeup, may be the source of the trahiras of the Iguaçu River.

Allozyme variation among three populations of the armored catfish Hypostomus regani (Ihering, 1905) (Siluriformes, Loricariidae) from the Paraná and Paraguay river basins, Brazil

“…Studies on fish population genetics have contributed to population management programs (Haig, 1998;SoleCava, 2001) and the detection of incipient ecological species (Dergam et al, 1998;Beheregaray and Sunnucks, 2001). In our present paper we have shown that the genetic distances between the different H. regani populations correlated with the geographic distance and river flow.…”

“…Marine fish populations have fewer barriers to gene flow and usually show less genetic differentiation than freshwater fishes (Gyllensten, 1985;Ward et al, 1994). Some migratory freshwater fish species such as P. lineatus (Revaldaves et al, 1997;Sivasundar et al, 2001) and P. corruscans (Sekine et al, 2002) show low genetic differentiation while poorly migratory or resident species such as H. malabaricus show high genetic differentiation (Dergam et al, 1998).…”

“…The wide geographical range of H. regani not only contrasts with the narrow distribution of most Hypostomus species but can also raise doubts about the conspecificity of H. regani populations. Studies of the genetic population structure of Neotropical fish have mainly focused on known migratory species such as Prochilodus lineatus (Characiformes, Prochilodontidae) (Revaldaves et al, 1997) and Pseudoplatystoma corruscans (Siluriformes, Pimelodidae) (Sekine et al, 2002), with studies on nonmigratory fish having been restricted to Hoplias malabaricus (Characiformes, Erythrinidae) (Dergam et al, 1998;Peres et al, 2002). We have no data about migratory behavior of H. regani, whether it is resident, short, medium or long distance migratory.…”

RAPD markers indicate the occurrence of structured populations in a migratory freshwater fish species

“…The potential use of RAPD in genetic mapping and population genetics has been widely documented for a large variety of organisms, including fish (Postlethwait et al, 1994;Foo et al, 1995;Bielawski and Pumo, 1997;Caccone et al, 1997;Dergam et al, 1998;Nadig et al, 1998;Liu et al, 1999).…”

Variação geográfica em Corydoras paleatus (Jenyns) (Siluriformes, Callichthyidae) do sul do Brasil

“…DERGAM et al (1998), demonstraram similaridade genética entre a população do rio Iguaçu com a população de cabeceira do rio Tibagi usando a técnica de estudo do polimorfismo do DNA amplificado ao acaso (RAPD). Esta técnica seria extremamente recomendável em complementação aos estudos da população de C. paleatus do rio Iguaçu.…”