Variação intraespecífica da cor da pelagem de uma espécie de pequeno roedor sul-americano

Intra-specific color variation is often underestimated by researchers, and among mammalian species, intra-specific differences in coloration are poorly documented for most species. The main goal of this study was to apply an objective color measurement methodology to the study of a specific problem: the detection, if any, of patterns of changes in the fur color of specimens of Akodon budini in relation to biological (i.e., sex) and environmental (i.e., season) variables. We hypothesize that male coat color will be more homogeneous than that of females and that the winter coat color will be darker than that of summer, the latter being orange. We measured the pelage color on five points over the dorsal surface of 26 A. budini museum specimens region using a spectroradiometer and a diffuse illumination cabin. We used Principal Component Analysis to describe the association between the color variables, sex and season, and each of the observations. We then used general linear models of Analysis of Variance to examine relationships between color data, season, and sex. The results clearly confirm the hypothesis related to seasonal coat color change but do not directly confirm the hypothesis related to changes in coat color in relation to sex, and we show the complexity of the studied pattern. In conclusion, undoubtedly, the studied variables should accordingly be taken into account when studying the coloration of specimens for characterization, identification and discrimination of different taxonomic units based on color.Variação de cor intra-específica é muitas vezes subestimada pelos pesquisadores, e entre espécies de mamíferos, as diferenças intra-específicas na coloração são pouco conhecidas para a maioria das espécies. O principal objetivo deste estudo foi aplicar uma metodologia objetiva de medição de cor para o estudo de um problema específico: a detecção de padrões de mudanças na cor da pele de espécimes de Akodon budini em relação a variáveis biológicas (i.e., sexo) e ambientais (i.e., temporada), se houver. Nossa hipótese é que a cor da pelagem do sexo masculino será mais homogênea do que a de fêmeas e que a cor da pelagem do inverno vai ser mais escura do que a de verão, sendo esta última mais laranja. Medimos a cor da pelagem em cinco pontos sobre a superfície dorsal de 26 espécimes de museu de A. budini usando um espectroradiômetro e uma cabine de iluminação difusa. Usamos Análise de Componentes Principais para descrever a associação entre as variáveis de cor, sexo e temporada, e cada uma das observações. Em seguida, usamos modelos lineares gerais da Análise de Variância para verificar as relações entre os dados de cor, temporada, e sexo. Os resultados confirmam claramente a hipótese relacionada à mudança sazonal de cor da pelagem, mas não confirmam diretamente a hipótese relacionada com alterações na cor da pelagem em relação ao sexo, e vamos mostrar a complexidade do modelo estudado. Em conclusão, sem dúvida, as variáveis estudadas devem consequentemente ser tidas em conta quando se estuda a coloração de amostras para caracterização, identificação e discriminação de diferentes unidades taxonômicas com base na cor.Fil: Sandoval Salinas, Maria Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; ArgentinaFil: Barquez, Ruben Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; ArgentinaFil: Colombo, Elisa Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; ArgentinaFil: Sandoval, Jose Domingo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentin

On the subjective determination of color in biological specimens: The case of the pelage of small mammals

En el ámbito de las Ciencias Biológicas, la determinación del color de los especímenes es de fundamentalimportancia para responder una amplia variedad de preguntas. Durante mucho tiempo, la determinación visual del color fue la regla. Posteriormente, se han desarrollado y utilizado varias cartas de color de referencia, tales como las del Sistema de Color de Munsell. Como una primera aproximación a la evaluación del desempeño deobservadores en la caracterización del color de especímenes biológicos en condiciones controladas de iluminación, se realizó un experimento psicofísico que implicó la determinación visual del color de especímenes biológicos (micromamíferos de la Colección Mamíferos Lillo, Facultad de Ciencias Naturales e Instituto Miguel Lillo, UNT), por parte de 21 observadores, utilizando 27 fichas de color de Munsell preseleccionadas como referencia. Como una primera aproximación, se puso a prueba la confiabilidad intra- e inter-observadores mediante un análisis descriptivo. Los resultados crudos revelan una confiabilidad intra-observadores muy baja (con un porcentaje promedio de coincidencia en la asignación de la misma ficha de color a los mismos especímenes del 20%). Por otro lado, considerando el número máximo de coincidencias en la asignación de una ficha de color por ejemplar, el 36,4% de las veces (en promedio) distintos observadores asignaron a los mismos ejemplares la ficha de color más elegida. Estos porcentajes mejoran notablemente cuando se flexibiliza la condición de detectar diferencias tan pequeñas como un paso en cualquiera de los tres atributos perceptuales del color (tono, valor y croma). De esta manera, el porcentaje promedio de coincidencia en la asignación de fichas de color equivalentes a los mismos especímenes fue del 68% mientras que el 57,5% de las veces (en promedio) distintos observadores asignaron a los mismos ejemplares las fichas de color equivalentes más elegidas. De los tres atributos perceptuales, cambios pequeños en el tono son los más difícilmente detectados.In the field of Biological Sciences, the determination of the color of the specimens is of fundamental importance to answer a wide variety of questions. For a long time, the visual determination of color was the rule. Subsequently, several reference color charts, such as those of the Munsell Color System, have been developed and used. As a first approach to the evaluation of the performance of observers in the characterization of the color of biological specimens under controlled lighting conditions, a psychophysical experiment was carried out involving the visual determination of color of biological specimens (small mammals of the Lillo Mammal Collection, Faculty of Natural Sciences and Miguel Lillo Institute, UNT), by 21 observers, using 27 Munsell color chips preselected as reference. As a first approach, intra- and inter-observer reliability was tested through a descriptive analysis. The crude results reveal very low intra-observer reliability (with an average percentage of coincidence in the assignment of the same color chip to the same specimens of 20%). On the other hand, considering the maximum number of coincidences in the allocation of a color chip per specimen, 36.4% of the times (on average) different observers assigned the most chosen color chip to the same specimens. These percentages improve markedly when the condition of detecting differences as small as one step in any of the three perceptual attributes of color (tone, value, and chroma) is relaxed. In this way, the average percentage of coincidence in the assignment of equivalent color chips to the same specimens was 68%, while 57.5% of the times (on average) different observers assigned to the same specimens the equivalent most chosen color chips. Of the three perceptual attributes, small changes in tone are the most difficult to detect.Fil: Sandoval Salinas, Maria Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; ArgentinaFil: Sandoval, Jose Domingo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; ArgentinaFil: Colombo, Elisa Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; Argentin

Biogeographical analysis of rodent endemism and distributional congruence in the southern-central Andes (north-western Argentina)

The recognition of areas of endemism (AEs) is important for conservation biology and biogeographical regionalization. Our objective was to quantitatively identify AEs and distributional congruence patterns of native rodents at the tropical/temperate transition in the central Andes. We analysed 6200 geo-referenced distributional records of 80 species in north-western Argentina using NDM/VNDM software. We found 20 AEs defined by 22 endemic species (27% of the total rodent fauna) and 34 patterns of distributional congruence in non-endemic rodents. Geographical range congruence follows two main patterns running parallel along the Andes. One is related to the humid eastern slopes of the Andes (Argentinean Yungas forest) and the other to the high Andes (Argentinean Puna plateau). Endemism was mainly restricted to the southernmost part of the Yungas forest and adjacent dryer valleys (Monte desert). Species diversity was highest in the northern sector of the Argentinean Yungas forest, where several species reach their southern distributional range. This incongruence among hotspots of diversity and endemism has also been also noted in diversity studies at continental and global scales. Our results provide a starting point for conservation planning in the southernmost Central Andes, which combines the taper of tropical diversity and range-restricted species endemic to the tropical–temperate transition.Fil: Sandoval Salinas, Maria Leonor. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferro, Luis Ignacio. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

阿根廷 Yungas 雨林特有翼手类和有袋类

Several studies have characterized the Yungas as a separate biogeographic unit, mainly based in floristic components. However, these characterizations were mainly qualitative and did not include faunal groups. The Yungas have been assumed as a region with rich floral and faunal diversity, but without testing how well they are described by animal distributions. Our study consists of a formal analysis of endemism based on distribution of small mammals in the southernmost portion of the Yungas. This area is biogeographically very interesting because the Yungas are comprised of discontinuous fragments of forests that extend into temperate arid and semiarid habitats. As a first approximation, we contrasted a group of volant species (bats) versus a group of non-volant species (marsupials). Our results show that small mammals are efficient indicators of endemism in Yungas. Eighty percent of the species of small marsupials included in the analysis supported the identified areas as being zones of endemism. Regarding bats, almost 55 percent of the species supported a designation of endemism. The results also show that the areas we considered are congruent with the botanical definition of the Yungas of northwestern Argentina and their subdivisions, an assumption that had not been previously tested with a formal quantitative method. We also found that nonvolant species are better indicators of endemism than volant ones at regional scales, but volant species are better indicators than was previously thought.摘要：有学者根据植物组成等特性将 Yungas 雨林定性为独立的生物地理单元，但这些特性主要是定性的且 未包括其动物区系组成。Yungas 雨林被认为是动植物种类分布丰富的多样性的区域。然而，尚未有研究评估其 动物分布记述的状况。在生物地理学上 Yungas 雨林使人充满兴趣，它函盖不连续分布的雨林且延伸至温带干旱 和半干旱地带。该研究分析了 Yungas 最南端地区小型哺乳动物特有种分布记录，对比了飞行物种（蝙蝠类）和 非飞行物种（有袋类）的分布。结果显示小型哺乳动物特有种是 Yungas 地区的有效指标；所分析的 80%小型有 袋类物种和 55%蝙蝠类物种支持所鉴定的区域作为特有种区域。所研究的区域与阿根廷西北部及其以下的 Yungas 的植物学定义一致。该区域以前尚未正式用定量方法评测。结果还发现非飞行特有种较之飞行特有种更 合适作为区域尺度上的特有种指标，作者认为飞行特物种作为特有种指标比以前所认为的要更好。Fil: Sandoval Salinas, Maria Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; ArgentinaFil: Szumik, Claudia Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; ArgentinaFil: Barquez, Ruben Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; Argentin

Taxonomic status of large- and middle-sized Calomys (Cricetidae: Sigmodontinae) from the southern central Andes inferred through geometric morphometrics of the skull

Calomys is one of the most polytypic and widely distributed genera of the Neotropical rodent fauna. The taxonomic hierarchy for the large- and middle-sized morphotypes from the southern central Andes (SCA; C. boliviae, C. callosus, C. fecundus, and C. venustus) has fluctuated repeatedly from synonyms or subspecies to valid species. As a first approach to the taxonomic resolution of the taxa complex of this genus inhabiting the SCA, we applied an integrative quantitative assessment of currently recognized species? cranial discrimination through the analysis of geometric morphometrics. The morphometric analyses revealed the presence of 3 distinct species of Calomys in northwestern and central Argentina. We corroborated the presence of a large amount of intraspecific variation with substantial overlap for the 3 species in the morphospace. The assessment indicates that 24% of skull size variation is due to differences among species. Calomys boliviae (including C. fecundus) was the largest among the studied species, whereas the differences were subtle between C. venustus and C. callosus. The relative contribution of interspecific differences to the total skull shape variation was lower than that of size and different among the cranial views?dorsal, ventral, and lateral?analyzed (between 8% and 16%). Moreover, static allometric size changes had a major effect on skull shape differences between species. So, including ecoregions and size-free shape, variables improved significantly the amount of interspecific differentiation. We highlight the usefulness of morphometric assessments to clarify and contribute to the taxonomy of Neotropical mice.Fil: Martínez, Juan José. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Sandoval Salinas, Maria Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Programa de Investigación de Biodiversidad Argentina; ArgentinaFil: Carrizo, Luz Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin