RESUMO

In the Atlantic forest of Rio de Janeiro, Callithrix aurita (É. Geoffroy in Humboldt, 1812) is a native species vulnerable to extinction and C. jacchus (Linnaeus, 1758) and C. penicillata (É. Geoffroy, 1812) are invasive species. The major threats to the native species are habitat degradation and hybridization, although there are currently no genetic data about natural hybrids available. Previous studies have revealed that species of the Callithrix genus are extremely homogeneous in their karyotypes with the exceptions of the morphology and size of the Y chromosome and its nucleolar organizer region (NOR) banding pattern. Three male marmosets captured in the wild in Guapimirim municipality, Rio de Janeiro, Brazil, considered as possible hybrids between C. aurita and C. jacchus or C. penicillata on the basis of pelage pattern, were cytogenetically studied. Metaphase chromosomes were obtained by using short-term lymphocyte cultures and Ag-NOR staining was performed. The hybrids karyotypes were 2n=46, 14 uni- and 30 bi-armed autosomes, a median size submetacentric X and NOR bearing autosomes, being compatible with that observed for the genus. In the three individuals studied, Y chromosomes were similar to those found for C. aurita, without NORs. The data obtained suggest the involvement of C. aurita in natural hybridization with one of the invasive species. We discuss the possible consequences of this hybridization.

No estado do Rio de Janeiro, em área de Mata Atlântica, Callithrix aurita (É. Geoffroy in Humboldt, 1812) é a espécie nativa considerada vulnerável à extinção e C. jacchus (Linnaeus, 1758) e C. penicillata (É. Geoffroy, 1812) são espécies invasoras. As principais ameaças à espécie nativa são a degradação do habitat e a hibridação, embora não haja, até o momento, dados genéticos que confirmem a hibridação natural. Estudos anteriores revelaram que as espécies do gênero Callithrix são extremamente homogêneas em seus cariótipos, diferindo quanto à morfologia do cromossomo Y e padrão de marcação da região organizadora de nucléolo (NOR). No presente estudo, três saguis machos capturados na natureza no município de Guapimirim, distrito de Teresópolis, RJ, considerados como possíveis híbridos entre C. aurita e C. jacchus ou C. penicillata, com base no padrão de pelagem, foram estudados citogeneticamente. Os cromossomos metafásicos foram obtidos pela técnica de cultura de linfócitos e a coloração Ag-NOR foi realizada. Os cariótipos dos híbridos, 2n=46, continham 14 autossomos com um braço e 30 com dois braços, um cromossomo X de tamanho médio submetacêntrico e marcação NOR nos autossomos, sendo compatíveis com aquele observado para o gênero. Nos três casos, o cromossomo Y foi similar ao observado em C. aurita, sem marcação NOR. Os dados obtidos sugerem a participação de C. aurita em hibridação natural com as espécies invasoras e suas prováveis consequências são discutidas.

RESUMO

Leucism is an inherited disorder, characterized by the lack of pigments in part or all of the body, normal coloration of the eyes and, in birds, in naked parts such as the bill and legs. This kind of disorder is sometimes erroneously designated as albinism or partial albinism. In this study, we present a case of leucism in a wild owl. The studied individual presented completely white plumage, light-yellow coloration of legs and bill and normal coloration of eyes. According to morphological features, this owl is a specimen of burrowing owl, Athene cunicularia (Molina, 1782). To confirm the species identity, we used cytogenetic analyses for karyotypic determination, comparing it to the previously described one in the literature. We also studied a captive female of A. cunicularia to complement the species karyotype, which was described in the literature based only on a single male. The karyotype of the leucistic owl individual was compatible with the previously published one for A. cunicularia, confirming the bird was a male specimen. Cytogenetic analysis of the captive female showed that the W sex chromosome is metacentric and comparable to the seventh pair in size. This is the first description of a case of leucism in A. cunicularia for South America. Long-term studies are needed in the Neotropical region to evaluate survival and breeding success in leucistic birds.

RESUMO

Leucism is an inherited disorder, characterized by the lack of pigments in part or all of the body, normal coloration of the eyes and, in birds, in naked parts such as the bill and legs. This kind of disorder is sometimes erroneously designated as albinism or partial albinism. In this study, we present a case of leucism in a wild owl. The studied individual presented completely white plumage, light-yellow coloration of legs and bill and normal coloration of eyes. According to morphological features, this owl is a specimen of burrowing owl, Athene cunicularia (Molina, 1782). To confirm the species identity, we used cytogenetic analyses for karyotypic determination, comparing it to the previously described one in the literature. We also studied a captive female of A. cunicularia to complement the species karyotype, which was described in the literature based only on a single male. The karyotype of the leucistic owl individual was compatible with the previously published one for A. cunicularia, confirming the bird was a male specimen. Cytogenetic analysis of the captive female showed that the W sex chromosome is metacentric and comparable to the seventh pair in size. This is the first description of a case of leucism in A. cunicularia for South America. Long-term studies are needed in the Neotropical region to evaluate survival and breeding success in leucistic birds.

RESUMO

In the Atlantic forest of Rio de Janeiro, Callithrix aurita (É. Geoffroy in Humboldt, 1812) is a native species vulnerable to extinction and C. jacchus (Linnaeus, 1758) and C. penicillata (É. Geoffroy, 1812) are invasive species. The major threats to the native species are habitat degradation and hybridization, although there are currently no genetic data about natural hybrids available. Previous studies have revealed that species of the Callithrix genus are extremely homogeneous in their karyotypes with the exceptions of the morphology and size of the Y chromosome and its nucleolar organizer region (NOR) banding pattern. Three male marmosets captured in the wild in Guapimirim municipality, Rio de Janeiro, Brazil, considered as possible hybrids between C. aurita and C. jacchus or C. penicillata on the basis of pelage pattern, were cytogenetically studied. Metaphase chromosomes were obtained by using short-term lymphocyte cultures and Ag-NOR staining was performed. The hybrids karyotypes were 2n=46, 14 uni- and 30 bi-armed autosomes, a median size submetacentric X and NOR bearing autosomes, being compatible with that observed for the genus. In the three individuals studied, Y chromosomes were similar to those found for C. aurita, without NORs. The data obtained suggest the involvement of C. aurita in natural hybridization with one of the invasive species. We discuss the possible consequences of this hybridization.

No estado do Rio de Janeiro, em área de Mata Atlântica, Callithrix aurita (É. Geoffroy in Humboldt, 1812) é a espécie nativa considerada vulnerável à extinção e C. jacchus (Linnaeus, 1758) e C. penicillata (É. Geoffroy, 1812) são espécies invasoras. As principais ameaças à espécie nativa são a degradação do habitat e a hibridação, embora não haja, até o momento, dados genéticos que confirmem a hibridação natural. Estudos anteriores revelaram que as espécies do gênero Callithrix são extremamente homogêneas em seus cariótipos, diferindo quanto à morfologia do cromossomo Y e padrão de marcação da região organizadora de nucléolo (NOR). No presente estudo, três saguis machos capturados na natureza no município de Guapimirim, distrito de Teresópolis, RJ, considerados como possíveis híbridos entre C. aurita e C. jacchus ou C. penicillata, com base no padrão de pelagem, foram estudados citogeneticamente. Os cromossomos metafásicos foram obtidos pela técnica de cultura de linfócitos e a coloração Ag-NOR foi realizada. Os cariótipos dos híbridos, 2n=46, continham 14 autossomos com um braço e 30 com dois braços, um cromossomo X de tamanho médio submetacêntrico e marcação NOR nos autossomos, sendo compatíveis com aquele observado para o gênero. Nos três casos, o cromossomo Y foi similar ao observado em C. aurita, sem marcação NOR. Os dados obtidos sugerem a participação de C. aurita em hibridação natural com as espécies invasoras e suas prováveis consequências são discutidas.

RESUMO

Leucism is an inherited disorder, characterized by the lack of pigments in part or all of the body, normal coloration of the eyes and, in birds, in naked parts such as the bill and legs. This kind of disorder is sometimes erroneously designated as albinism or partial albinism. In this study, we present a case of leucism in a wild owl. The studied individual presented completely white plumage, light-yellow coloration of legs and bill and normal coloration of eyes. According to morphological features, this owl is a specimen of burrowing owl, Athene cunicularia (Molina, 1782). To confirm the species identity, we used cytogenetic analyses for karyotypic determination, comparing it to the previously described one in the literature. We also studied a captive female of A. cunicularia to complement the species karyotype, which was described in the literature based only on a single male. The karyotype of the leucistic owl individual was compatible with the previously published one for A. cunicularia, confirming the bird was a male specimen. Cytogenetic analysis of the captive female showed that the W sex chromosome is metacentric and comparable to the seventh pair in size. This is the first description of a case of leucism in A. cunicularia for South America. Long-term studies are needed in the Neotropical region to evaluate survival and breeding success in leucistic birds.