Navegando por Assunto "Ancistrinae"

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Acesso aberto (Open Access)
Cytogenetic analysis of Baryancistrus xanthellus (Siluriformes: Loricariidae: Ancistrini), an ornamental fish endemic to the Xingu River, Brazil
(Sociedade Brasileira de Ictiologia, 2016) MEDEIROS, Larissa Azevedo de; GURGEL, Eduardo Gentil Ginani; SOUSA, Leandro Melo de; PY-DANIEL, Lúcia Helena Rapp; FELDBERG, Eliana
Baryancistrus xanthellus is a species from the Ancistrini tribe known commonly as "amarelinho " or "golden nugget pleco". It is one of the most popular and valued ornamental fishes due to its color pattern. Also, it is an endemic species from the Xingu River occurring from Volta Grande do Xingu, region where the Belo Monte Hydropower Dam is being built, to São Félix do Xingu. The current study aimed to cytogenetically characterize B. xanthellus . Results point to the maintenance of 2n=52, which is considered the most common condition for the tribe, and a single nucleolus organizer region (NOR). Mapping of the 18S rDNA confirmed the NOR sites, and the 5S rDNA was mapped in the interstitial position of a single chromosome pair. The 18S and 5S rDNA located in different pairs constitute an apomorphy in Loricariidae. Large blocks of heterochromatin are present in pairs 1 and 10 and in the regions equivalent to NOR and the 5S rDNA. Data obtained in this study corroborated with the currently accepted phylogenetic hypothesis for the Ancistrini and demonstrate evidence that the genus Baryancistrus occupies a basal position in the tribe.
Acesso aberto (Open Access)
Descrição cariotípica de peixes dos gêneros Baryancistrus, Parancistrus, Peckoltia e Ancistrus (Ancistrinae, Loricariidae) da Bacia Amazônica
(Universidade Federal do Pará, 2003-06-13) SOUZA, Augusto Cesar Paes de; PIECZARKA, Julio Cesar; http://lattes.cnpq.br/6644368250823351
The subfamily Ancistrinae is one of the most diversified among Loricariidae fish, including approximately 200 species, distributed in 26 genera. These fish are easily recognized by the presence of bony plates arranged in series along the body, and by the antero-ventral position of the mouth. Their common names are acaris, bodós, cascudos and sucker-mouth. Species of the subfamily Ancistrinae comprise an important social-economic resource, constituting one of the most important commercial activities in Altamira-PA. In this study, the karyotype of nine species of fish belonging to four different genera (Baryancystrus, Parancistrus, Peckoltia and Ancistru,$) of the subfamily Ancistrinae were analyzed through conventional (Giemsa, C-band and Ag-NORs) and fluorochrome (Chromomycin A3) techniques. The species of the genus Baryancistrus showed a diploid number 2n= 52, and FN=104. NORs were found in an interstitial position of the short arm of a biarmed chromosome. The species B. aff niveatus had large blocks of constitutive heterochromatin, rich in G-C. This character was considered apomorphic. Hence, the karyotype of this species was considered the most derived among the species of this genus. Genus Parancistrus includes species with a karyotypic structure very similar to the one found in Baryancistrus, and the position of NORs could be considered as a possible apomorphy shared by these two genera. The species of the genus Peckoltia showed a diploid number with 52 chromosomes, and FN=102, with large heterochromatic blocks in ali the species. These blocks comprised almost ali the long arras of some submetacentric and subtelocentric chromosome pairs, which could be considered as a possible apomorphy shared by the species of this group. NORs were found in the long arm of a submetacentric pair in P. vittata, and in the maximum of three chromosomes in Peckoltia spl and Peckoltia sp2. Ancistrus ranunculus showed the most derived karyotype among all the species analyzed in this study. This karyotype had 48 chromosomes and FN=80. Cytogenetic analyses so far suggest that inversions were the most important rearrangement that occurred during the chromosomal diversification of Ancistrinae, except in Ancistrus ranunculus, in which Robertsonian rearrangements were also observed.