ABSTRACT Variation in the morphometry of individuals in a population may result from natural or sexual selection. In the present study we investigated morphometric differences between males and females of a bird species endemic to the Brazilian Atlantic Forest, the Hangnest Tody-Tyrant, Hemitriccus nidipendulus (Wied, 1831), with no apparent sexual dimorphism. All individuals (n = 56) were sexed by PCR amplification of the intronic fragments of the CHDZ/CHDW alleles obtained from blood samples, and 12 morphometric measurements were recorded. The molecular configuration was similar to that described for other species of Passeriformes, with males presenting a single band of approximately 360 base pairs (bp), and females with two bands of 360 and 400 bp. Males had significantly larger tarsi and wings than the females, while the females had two larger beak measurements. This indicates that differential selection pressures may be modeling the morphometry of the Hangnest Tody-Tyrant. In the males, larger tarsi and wings may be beneficial for the exploration of the habitat or the acquisition of potential mates, while females with larger beaks may be able to exploit larger food items and forage more efficiently. However, these hypotheses need to be tested empirically in future studies.

Abstract: Here we describe an eight-year-old miniature schnauzer (MS) dog from Brazil with Persistent Mullerian Duct Syndrome (PMDS) and the single base pair substitution in AMHR2 exon 3, first detected in this breed in the USA. This finding is evidence of mutation dissemination to South America. In PMDS, a type of XY Disorder of Sex Development (DSD), dogs with a male karyotype and external phenotype also have a uterus, oviducts, and a cranial vagina internally. Approximately half of PMDS MS are unilaterally or bilaterally cryptorchid and many develop pyometra and/or Sertoli cell tumor. Bilateral Sertoli cell testicular tumors were present in this case, and the dog died a few days after surgical castration and hysterectomy. Although the karyotype was compatible with male chromosomal sex, a Robertsonian translocation was also identified, which may be an incidental finding. This report emphasizes the importance of cytogenetic and molecular genetic analyses, along with clinical examination, to identify chromosomal or genetic variations associated with canine PMDS. These are helpful tools to obtain early diagnosis in the MS, which is important to improve health outcomes for affected dogs and to reduce the prevalence of PMDS and cryptorchidism in this breed by avoiding the mating of carriers.

ABSTRACT The birth of fraternal twins is a characteristic frequently observed in callitrichids. Cytogenetic studies have demonstrated hematopoietic chimerism in marmosets with the occurrence of two cell lines 2n=46,XX/46,XY in females and males co-twins, without phenotypic changes. Amplification by PCR have also been used to verify the presence of the SRY gene in female chimaeras. Our aim was to verify the occurrence of chimerism in Callithrix sp. individuals considered as hybrids according to their intermediate phenotypes between C. jacchus and C. penicillata. Blood samples from 37 Callithrix sp. individuals were collected. Hematopoietic chimerism 2n=46,XX/46,XY was detected by cytogenetic analysis in five individuals, three males and two females. A fragment of approximately 200bp of the SRY gene was amplified in seven females with normal external genitalia. The percentage of 32% of chimeric individuals detected in the present study is similar to that observed for pure specimens of Callithrix. These data suggests that hybridization probably does not interfere with the occurrence of twin gestation, nor of chimerism. Although cytogenetics is the main tool to identify the two cell lineages present in cases of chimerism, the amplification of the SRY gene by PCR has proved to be more efficient to identify the Y chromosome in cases of chimeric female marmoset.

ABSTRACT Despite extensive habitat fragmentation, the Neotropical region possesses 30% of the world´s bird species. Microsatellites have remained one of the most popular genetic markers and have been used in ecological and conservation studies since the 1990’s. We conducted a literature review comparing the number of papers published from January 1990 to July 2015 that used microsatellite markers for studies of wild birds in the Neotropical region, USA and some European countries. We assigned the articles to three categories of studies: population genetics, animal behavior/kinship analysis and the development of species-specific bird microsatellite markers. We also compared the studies in the Neotropics that used heterologous versus species-specific markers and provide a list of heterologous markers of utility in multiple birds. Despite the rich bird fauna in the Neotropics, the number of articles published represents only 5.6% of that published by the USA and selected European countries. Within the Neotropical region, Brazil possessed 60.5% of the total papers published, with the remaining 39.5% shared between five countries. We conclude that the lack of specialized laboratories and resources still represents a limit to microsatellite-based genetic studies of birds within the Neotropical region. To overcome these limitations, we suggest the use of heterologous microsatellite markers as a cost-effective and time-effective tool to assist ecological studies of wild birds.

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.

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.

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.

Foram estudados pela primeira vez os cariótipos de duas espécies do gênero Aratinga, A. guarouba e A. acuticaudata. As metáfases foram obtidas utilizando-se o método de cultura de curta duração de polpa de penas jovens. Estes cariótipos foram comparados com outros do mesmo gênero. Interpretações cariológicas na ordem Psittaciformes são discutidas.

The karyotypes of two species of Psittacidae of the genus Aratinga, Aratinga guarouba and A. acuticaudata were studied for the first time. The metaphases were obtained using a short term culture of feather pulp. These karyotypes are compared with others of the genus and their karyological relationships in the Psittaciformes are discussed