A new species of Astyanax (Characiformes: Characidae) from the rapids of the lower rio Xingu, Brazil

Lima, Flávio C. T.; Zuanon, Jansen

doi:10.1590/s1679-62252004000300002

Cited by 7 publications

(4 citation statements)

References 7 publications

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“…Rheophily, the behaviour of inhabiting high‐energy aquatic environments, such as occurs in all species of Archolaemus , is a phenomenon that is widespread among freshwater fishes, albeit limited to a small subset of the total number of species in the geographically extensive ichthyofaunas encompassing such swift water specialist species (Kullander, 1988; Lima & Zuanon, 2004; de Santana & Vari, 2010a). Adaptations for rheophily are myriad, but in some instances are apparently limited to behavioural strategies, or at least would seem to be so restricted based on externally obvious morphological adaptations.…”

Section: Methodsmentioning

confidence: 99%

South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles

Vari

Santana

Wosiacki

2012

Zoological Journal of the Linnean Society

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Neotropical electric knifefishes of the family Sternopygidae previously considered to represent a single relatively geographically widespread and morphologically variable species, Archolaemus blax, were analysed and found to represent a complex of five species, four of which are new to science. A fifth undescribed species from the Rio São Francisco basin outside the previous known range of the genus was identified. Recognized species of Archolaemus are: A. blax, previously thought to occur in the Rio Araguari, Rio Branco, Rio Tapajós, Rio Tocantins, and Rio Xingu, but which instead proved to be endemic to the Rio Tocantins; Archolaemus ferreirai sp. nov. from the Rio Mucajaí and Rio Uraricoera in the north‐eastern portions of the Amazon basin; Archolaemus janeae sp. nov. of the Rio Xingu and the upper Rio Tapajós, both southern tributaries of the mainstream Amazon; Archolaemus luciae sp. nov. of the Rio Trombetas, Rio Jari, and Rio Tapajós basins of the eastern Amazon, and the independent Rio Araguari draining into the Atlantic Ocean north of the mouth of the Amazon; Archolaemus orientalis sp. nov. of the São Francisco basin in eastern Brazil; and Archolaemus santosi sp. nov. of the Rio Jamari in the south‐western portion of the Amazon basin. The phylogenetic placements of Archolaemus and the recently described genus Japigny relative to the other members of the Eigenmanninae are discussed. A series of synapomorphies for Archolaemus are proposed and a hypothesis of the relationships within that genus is advanced. Rheophily of all members of Archolaemus is discussed, with the genus found to be the most specious clade within the Gymnotiformes living primarily in high‐energy settings. The reported anterior projection of the dentary teeth in A. blax was found to be a consequence of postmortem displacement.

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Section: Methodsmentioning

confidence: 99%

South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles

Vari

Santana

Wosiacki

2012

Zoological Journal of the Linnean Society

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“…As discussed by Lima & Zuanon (2004), the dark midlateral stripe in small characids can be categorized (without implied homology) as narrow and straight (e.g., Hyphessobrycon cachimbensis Travassos and Moenkhausia petymbuaba); broad and straight (e.g., Moenkhausia phaenota Fink, and Moenkhausia heicoi Géry & Zarske), or broad and curved (e.g., Nematobrycon and Inpaichthys). Moenkhausia plumbea and M. clorophthalma have a broad and ventrally curved dark midlateral stripe somewhat similar to Nematobrycon and Inpaichthys except in being more diffuse.…”

Section: Distributionmentioning

confidence: 99%

Two new species of Moenkhausia Eigenmann (Characiformes: Characidae) from Serra do Cachimbo, Pará, Northern Brazil

2010

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Two new species of Moenkhausia, one from the rio Tapajós and the other from the rio Xingu basins are described as apparently endemics of the Serra do Cachimbo. Both species, along with M. petymbuaba, share a distinct color pattern composed of large conspicuous dark blotches on the base of the body scales. Moenkhausia chlorophthalma, from rio Treze de Maio, a tributary to rio Curuá (rio Xingu basin), is distinguished by the presence of a proximal well delimited black area on the adipose fin and a green eye in life. Moenkhausia plumbea of the headwaters of tributaries of the rio Braço Norte, rio Tapajós basin is diagnosed by the presence of a dark longitudinal stripe across the eye and six branched pelvic-fin rays (vs. seven). Relationships of the new species with other Moenkhausia are discussed.Duas espécies novas de Moenkhausia, uma da bacia do rio Tapajós e outra da bacia do rio Xingu, são descritas como aparentemente endêmicas da Serra do Cachimbo. Ambas, juntamente com M. petymbuaba, compartilham um padrão de colorido exclusivo de grandes manchas escuras conspícuas na base das escamas do corpo. Moenkhausia chlorophthalma, do rio Treze de Maio, um afluente do rio Curuá (bacia do rio Xingu), é facilmente reconhecida pela presença de uma área preta bem delimitada na região anterior da nadadeira adiposa e possuir olhos verdes em vida. Moenkhausia plumbea ocorre nas cabeceiras dos afluentes do rio Braço Norte, bacia do rio Tapajós, e pode ser diagnosticada pela presença de uma faixa longitudinal escura no olho e seis raios ramificados na nadadeira pélvica (vs. sete). As relações entre as novas espécies com as demais Moenkhausia são discutidas.

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“…Over the past few years, some new species have been identified, most of them inhabiting small rivers and/or streams, such as: A. cremnobates and A. brachypterygium (Bertaco and Malabarba 2001); A. biotae (Castro and Vari 2004); A. dnophos (Lima and Zuanon 2004); A. totae (Haluch and Abilhoa 2005); A. elachylepis (Bertaco and Lucinda 2005); A. microschemos and A. pelecus (Bertaco and Lucena 2006); A. henseli (Melo and Buckup 2006), and A. bockmanni (Vari and Castro 2007).…”

Section: Introductionmentioning

confidence: 99%

Astyanax bockmanni Vari and Castro, 2007: an ambiguous karyotype in the Astyanax genus

2008

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Despite the widespread distribution of Astyanax bockmanni in streams from Upper Paraná River system in central, southeastern, and southern Brazil, just recently, it has been identified as a distinct Astyanax species. Cytogenetic studies were performed in two populations of this species, revealing conservative features. A. bockmanni shows 2n = 50 chromosomes, a karyotypic formula composed of 10 M + 12SM + 12ST + 16A and multiple Ag-NORs. Eight positive signals in subtelocentric/acrocentric chromosomes were identified by fluorescent in situ hybridization (FISH) with 18S rDNA probes. After FISH with 5S rDNA probes, four sites were detected, comprising the interstitial region of a metacentric pair and the terminal region on long arms of another metracentric pair. Little amounts of constitutive heterochromatin were observed, mainly distributed at distal region in two chromosomal pairs. Additionally, heterochromatin was also located close to the centromeres in some chromosomes. No positive signals were detected in the chromosomes of A. bockmanni by FISH with the As-51 satellite DNA probe. The studied species combines a set of characteristics previously identified in two different Astyanax groups. The chromosomal evolution in the genus Astyanax is discussed.

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A new species of Astyanax (Characiformes: Characidae) from the rapids of the lower rio Xingu, Brazil

Cited by 7 publications

References 7 publications

South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles

South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles

Two new species of Moenkhausia Eigenmann (Characiformes: Characidae) from Serra do Cachimbo, Pará, Northern Brazil

Astyanax bockmanni Vari and Castro, 2007: an ambiguous karyotype in the Astyanax genus

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