4 results on '"Rocha Barbosa, Oscar"'
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2. Sympatry between species of Juliomys (Rodentia: Sigmodontinae) along an altitudinal gradient in the Serra da Bocaina National Park.
- Author
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Cláudia Delciellos, Ana, Aguieiras, Marcia, Colombo de Mendonça, Gabriela, Carolina Loss, Ana, Rocha-Barbosa, Oscar, and Geise, Lena
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NATIONAL parks & reserves , *BIOGEOGRAPHY , *RODENTS , *KARYOTYPES , *CYTOCHROME b - Abstract
The altitudinal gradient found in the Atlantic Forest may play a role in establishing sympatry areas between congeneric species of sigmodontine rodents. For some genera with cryptic species, the elucidation of spatial patterns of distribution may be useful to understand reproductive isolation and speciation patterns, as well as spatial and temporal factors determining the boundaries of species' geographical distributions. Here we evaluated the occurrence of sympatry between Juliomys species along an altitudinal gradient in the Serra da Bocaina National Park (SBNP). Additionally, we review the occurrence of J. rimofrons and add new records of species occurrence in the SBNP, aided by karyological and molecular data. The study was carried out at four sites in the SBNP, which ranged between 770 and 1,200 m a.s.l. We captured 24 Juliomys specimens. Six out of 24 specimens were collected and karyotyped. For J. pictipes, the karyotype had a 2n of 36 and a FN of 34, and for J. ossitenuis 2n of 20 and FN of 36. Seventeen out of 24 Juliomys specimens were used in the cytochrome b phylogeny: 12 specimens grouped with J. pictipes and five with J. ossitenuis. Additionally, a specimen previously identified as J. rimofrons (MN 77793) clustered together with J. pictipes. Juliomys pictipes and J. ossitenuis were found in sympatry in two out of four sites in altitudes higher than 1,000 m a.s.l.. Our karyological and molecular data provided the detection of two Juliomys species in the SBNP for the first time (J. pictipes and J. ossitenuis) and disregarded the previous record of J. rimofrons. Our record of sympatry between J. pictipes and J. ossitenuis represents the fifth known record of sympatry between these species up to date. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
3. Biomechanics and skull variation in Leposternon Wagler, 1824 (Reptilia: Amphisbaenia)
- Author
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Hohl, Leandro dos Santos Lima, Rocha-barbosa, Oscar, Casas, Concepción Azorit, Grillo, Orlando Nelson, Santori, Ricardo Tadeu, and Barros-filho, José Duarte de
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Crânio ,Cobra - Morfologia ,Répteis ,Kinematics ,Biogeography ,Biogeografia ,Performance ,CIENCIAS BIOLOGICAS::ZOOLOGIA [CNPQ] ,Skull ,Squamata ,Cinemática ,Desempenho ,Imagem tridimensional - Abstract
Submitted by Boris Flegr (boris@uerj.br) on 2020-11-08T17:27:35Z No. of bitstreams: 3 Tese_Completa_parte1_Leandro Hohl.pdf: 7424447 bytes, checksum: a5924255cc2be11a1318f21aeaf5c29b (MD5) Tese_Completa_parte2_Leandro Hohl.pdf: 9163832 bytes, checksum: cc1b48211d38cc1e8a3e3f0286aa4bae (MD5) Tese_Completa_parte3_Leandro Hohl.pdf: 12156995 bytes, checksum: deab5fd7cbf8c6ddf857a29d7c42960b (MD5) Made available in DSpace on 2020-11-08T17:27:35Z (GMT). No. of bitstreams: 3 Tese_Completa_parte1_Leandro Hohl.pdf: 7424447 bytes, checksum: a5924255cc2be11a1318f21aeaf5c29b (MD5) Tese_Completa_parte2_Leandro Hohl.pdf: 9163832 bytes, checksum: cc1b48211d38cc1e8a3e3f0286aa4bae (MD5) Tese_Completa_parte3_Leandro Hohl.pdf: 12156995 bytes, checksum: deab5fd7cbf8c6ddf857a29d7c42960b (MD5) Previous issue date: 2019-02-25 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior The Amphisbaenia have a fossorial habit and belong to the Squamata group. The genus Leposternon is represented by species that occur in almost all Brazilian states. With the exception of Leposternon microcephalum, which also occurs in Bolivia, Paraguay, Argentina and Uruguay, all other species are endemic to Brazil. They have several morphological adaptations to a fossorial lifesyle, which includes a heavily ossified and compacted skull. This assumes four morphotypes, which are associated with different types of excavation. The study of excavation modes, involving kinematics and locomotor performance, as well as 3D structural analysis and cranial morphological variations have been performed within the genus Leposternon. However, observations and models proposed by biomechanical studies do not directly associate cranial morphological variations with the type of movement and locomotor performance produced by the animal. In addition, the cranial variations in Leposternon are based only on descriptive analyzes. The objective of the present study was to verify inter- and intraspecific cranial morphological variations through the Geometric Morphometrics technique and to associate such variations with the locomotor performance of these animals, and to create a three-dimensional model for biomechanical studies, aligning the virtual model of the skeleton with videofluoroscopy images (Scientific Rotoscopy). Significant morphological variations were found among species, and these were related to body size and geographic distribution of specimens. As subtle differences in cranial size or shape may represent significance in bite force and digging capacity and in excavation speed, the cranial variation found between species and Leposternon specimens may directly influence their diet and locomotor performance. Leposternon microcephalum and L. scutigerum are morphometrically distinct species. The first is shorter and robust, with a wider head while the other is longer and thin, with a narrower head. They share the same digging movements. The animals analyzed reached relatively high speeds, but individuals with narrower skulls dug faster. A negative correlation between skull velocity and width was determined, but not with the total length or diameter of the body. The analysis of the biomechanics of the three-dimensional skeleton of a L. microcephalum specimen in the virtual environment was determinant for an even more detailed description of its excavation behavior revealing the effective participation of other structures, such as the ribs, in the excavation concern. We can state that the reliability and complexity of descriptions of cranial variations and locomotor performance and behavior increase according to the use of innovative techniques and methods. Os Amphisbaenia possuem hábito fossorial e pertencem ao grupo Squamata. O gênero Leposternon é representado por espécies que ocorrem em quase todos os Estados do Brasil. Com a exceção de Leposternon microcephalum, que ocorre também na Bolívia, Paraguai, Argentina e Uruguai, todas as outras espécies são endêmicas do Brasil. Possuem diversas adaptações morfológicas que permitem um modo de vida fossorial, incluindo um crânio fortemente ossificado e compacto. Este assume quatro morfotipos, os quais estão associados a diferentes tipos de escavação. O estudo dos modos de escavação, envolvendo cinemática e desempenho locomotor, bem como análises estruturais 3D e variações morfológicas cranianas tem sido realizados dentro do gênero Leposternon. Porém, observações e modelos propostos pelos estudos de biomecânica não associam, diretamente, variações morfológicas cranianas com o tipo de movimento e desempenho locomotor produzido pelo animal. Além disso, as variações cranianas em Leposternon são baseadas apenas em análises descritivas. Sendo assim, os objetivos do presente estudo foram verificar variações morfológicas cranianas intere intraespecíficas por meio da técnica de Morfometria Geométrica e associar tais variações ao desempenho locomotor desses animais, e criar um modelo tridimensional para estudos biomecânicos, alinhando o modelo virtual do esqueleto com imagens sequenciais do movimento em fluoroscopia (rotoscopia científica). Variações morfológicas significativas foram encontradas entre as espécies, e estas se relacionam ao tamanho do corpo e à distribuição geográfica dos espécimes. Como diferenças sutis no tamanho ou forma do crânio podem representar significância na força de mordida e capacidade de escavação, e na velocidade de escavação, a variação craniana encontrada entre as espécies e espécimes de Leposternon pode influenciar diretamente sua dieta e desempenho locomotor. Leposternon microcephalum e L. scutigerum são espécies distintas morfometricamente. A primeira é mais curta e robusta, com uma cabeça mais larga enquanto o outro é mais alongada e afilada, com uma cabeça mais estreita. Elas compartilham os mesmos movimentos de escavação. Os animais analisados atingiram velocidades relativamente altas, mas indivíduos com crânios mais estreitos cavaram mais rápido. Uma correlação negativa entre a velocidade e a largura do crânio foi determinada, mas não com o comprimento total ou diâmetro do corpo. A análise da biomecânica do esqueleto tridimensional de um exemplar de L. microcephalum no ambiente virtual foi determinante para uma descrição ainda mais detalhada sobre seu comportamento escavatório revelando a participação efetiva de outras estruturas, como as costelas, no processo de escavação. Podemos afirmar que a confiabilidade e a complexidade das descrições das variações cranianas e do comportamento e desempenho locomotor, aumentam de acordo com a utilização de técnicas e métodos inovadores.
- Published
- 2019
4. Juliomys rimofrons Oliveira and Bonvicino, 2002 (Rodentia: Cricetidae): Distribution extension.
- Author
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Fonseca, Raul, Bergallo, Helena Godoy, Delciellos, Ana Cláudia, Rocha-Barbosa, Oscar, and Geise, Lena
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CRICETIDAE , *BIOGEOGRAPHY , *SPECIES , *RODENTS , *MORPHOLOGY , *NATIONAL parks & reserves - Abstract
Until now, Juliomys rimofrons Oliveira and Bonvicino, 2002 has been known only from the type locality, the county of Itamonte, State of Minas Gerais, Brazil. Based on morphological and karyological examinations, in this study we identified two new records for this species. Both records correspond to individuals collected at Serra da Bocaina National Park, in the states of Rio de Janeiro and São Paulo, Brazil. These records increase the species' geographic range southwards, approximately 100 km from the type locality. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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