Anatomia comparada e morfometria de oligoryzomys nigripes e o. flavescens (rodentia, sigmodontinae) no Rio Grande do Sul, Brasil

Machado, Leonardo F.; Paresque, Roberta; Christoff, Alexandre Uarth

doi:10.1590/s0031-10492011000300001

Cited by 15 publications

(19 citation statements)

References 23 publications

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“…Despite the high diversity of Sigmodontinae and its extensive occupation of different environments, relatively few studies have been conducted on locomotor habits and associated morphological variation in this group. Most of these studies have focused on the ecology of the different forms found in the Atlantic Forest, but few have addressed the anatomy of the postcranial skeleton and its functional morphology (Lund,1840; Stein,1988; Neves,2003; Machado et al,2011).…”

Section: Introductionmentioning

confidence: 99%

“…Notwithstanding the number of recent studies documenting taxonomic variation in appendicular characters at the specific level (e.g., Costa et al,2011; Machado et al,2011), there remains a lack of comparative studies of the appendicular morphology of sigmodontine rodents. This is particularly unfortunate, because most of the rodent fossil remains from Brazilian paleontological sites consist of isolated appendicular fragments generally deposited in caves as owl pellets.…”

Section: Introductionmentioning

confidence: 99%

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Morphological variation in the appendicular skeleton of atlantic forest sigmodontine rodents

Coutinho

Oliveira

Pessôa

2013

Journal of Morphology

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Rodents of the subfamily Sigmodontinae comprise a highly diversified group in the Atlantic Forest, with semifossorial, terrestrial, semiaquatic, scansorial, and arboreal forms. In this study, we analyzed morphometric variation in humerus, scapula, ulna, radius, femur, tibia, and pelvis to investigate its possible relationship with the different types of locomotion recorded in the literature. Skeletal characters were measured in 321 specimens belonging to 29 species and 19 genera either restricted to or recorded in this ecoregion. Multivariate morphometric analyses (principal component and canonical variate analyses) arranged individuals of different genera in groups congruent with the different types of locomotion. This arrangement was more clearly defined when analyses included only forelimb measurements, indicating that most of the variation in appendicular traits associated with the different locomotor modes occurs in the forelimb skeleton. Semifossorial forms exhibited the most distinct appendicular morphology, as well as the greatest frequency of endemism among analyzed species. These results suggest that this mode of locomotion led to greater differentiation in semifossorial Atlantic forest sigmodontines than in terrestrial and arboreal forms, which were found to have more subtle differentiation and fewer endemics. Scansorial species could not be set apart from terrestrial ones in terms of appendicular morphology, suggesting that these two modes of locomotion are the most similar and generalized for the group, as they occur in most lineages in the subfamily. The results of this study corroborate previous observations on the relevance of appendicular characters in the differentiation of species and genera in the subfamily Sigmodontinae.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morphological variation in the appendicular skeleton of atlantic forest sigmodontine rodents

Coutinho

Oliveira

Pessôa

2013

Journal of Morphology

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“…The species Oligoryzomys flavescens (subfamily Sigmodontinae, tribe Oryzomyini) is distributed throughout much of the Brazilian Atlantic Forest, and it can also be found in southern Brazil and parts of Argentina, Paraguay and Uruguay, occupying forest, grassland and anthropogenic habitats (Reis et al, 2006;Miranda et al, 2009). It is a small species, with the body length of adults ranging between approximately 81 and 93 mm, with a color ranging from brown to light brown and thin, long legs with clear foot and interdigital pads (Bonvicino et al, 2008;Machado et al, 2011). Initial field observations indicated that the feet of the juveniles of this species are large in comparison to the rest of the body, which is the origin of this research.…”

Section: Introductionmentioning

confidence: 92%

Ontogenetic allometry in the foot size of Oligoryzomys flavescens (Waterhouse, 1837) (Rodentia, Sigmodontinae)

et al. 2015

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Ontogenetic allometry is the study of how the size or shape of certain structures changes over the course of an animal's development. In this study, using Huxley's formula of allometric growth (1932), we assessed the changes in the rate of growth of the feet size of the sigmodontine rodent Oligoryzomys flavescens during its ontogeny and compared differences between males and females. We find evidence of a change of polarity during the ontogenetic development of the species, with the presence of positive allometry during pregnancy and negative allometry in adulthood. Moreover, we note the presence of sexual dimorphism in the size of the feet, in which males of the species have a higher rate of growth than females. This growth pattern is positively related to escape from predators in childhood in both sexes and, in adulthood, provides a higher encounter rate of females by males, due to the larger displacement of the latter. We suggest that both the forces of natural selection and sexual selection have acted to shape the evolution of foot size in this species.Keywords: linear measures, ontogenetic trajectory, bipedal locomotion, sexual dimorphism. Alometria ontogenética no tamanho dos pés em Oligoryzomys flavescens(Waterhouse, 1837) (Rodentia, Sigmodontinae) ResumoA alometria ontogenética estuda como o tamanho ou forma de determinada estrutura muda ao longo do desenvolvimento. Neste estudo, através da fórmula do crescimento alométrico de Huxley (1932), acessamos as variações na taxa de crescimento do tamanho dos pés do roedor sigmodontineo Oligoryzomys flavescens, ao longo de sua ontogenia e entre machos e fêmeas. Nós encontramos evidência de uma mudança de polaridade ontogenética ao longo do desenvolvimento da espécie, com presença de alometria positiva na fase gestacional, e alometria negativa na fase adulta. Além disso, constatamos a presença de dimorfismo sexual no tamanho dos pés, onde machos da espécie apresentam uma maior taxa de crescimento nesta característica em comparação com as fêmeas. Esse padrão de crescimento deve estar positivamente relacionado com a fuga de predadores na infância em ambos os sexos, e na vida adulta propicia uma maior taxa de encontro de fêmeas pelos machos, devido ao maior deslocamento destes últimos. Sugerimos que tanto as forças da seleção natural quanto da seleção sexual tem atuado para moldar a evolução do tamanho dos pés nesta espécie.Palavras-chave: medidas lineares, trajetória ontogenética, locomoção bípede, dimorfismo sexual.

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“…Trata-se de uma maneira de analisar os parâmetros corporais que podem auxiliar na verificação do dimorfismo sexual das espécies 1 . Permite também avaliar a variação intraespecífica, bem como a interespecífica e é um aspecto importante no diagnóstico característico dos organismos.…”

Section: Introductionunclassified

Estudo morfométrico de Gliricola quadrisetosa Ewing, 1924 recuperado em Galea spixii Wagler, 1831

et al. 2014

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O estudo morfométrico de piolhos que acometem Galea spixii auxilia na compreensão da taxonomia desse Phithraptera. O trabalho objetivou realizar a morfometria de espécimes de Gliricola quadrisetosa recuperados em G. spixii. As análises foram realizadas com auxílio de microscópio óptico de luz. Os dados foram apresentados na forma de média simples e desvio padrão. Os machos e fêmeas apresentaram um comprimento médio corporal de 98,01±2,43 e 117,97±4,75 µm; da face inferior da cabeça de 16,42±3,41 e 18,43±2,61 µm; do protórax de 12,43±0,91 e 13,79±1,13 µm e do pterotórax de 13,57±1,07 e 14,88±1,84 µm, respectivamente. A genitália do macho apresentou em sua placa basal comprimento respectivo da margem lateral externa e interna de 28,86±1,29 e 21,88±1,91 µm; do ramo externo e interno de 2,94±0,38 e 7,25±0,72 µm. Na genitália da fêmea, o comprimento da porção superior e inferior foi respectivamente de 25,35±2,32 e 28,18±2,86 µm. As 11 cerdas apresentaram comprimento médio de 2,99±0,17 µm. As medidas obtidas contribuirão para padronização da taxonomia de Gliricola quadrisetosa recuperados em Galea spixii.

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Anatomia comparada e morfometria de oligoryzomys nigripes e o. flavescens (rodentia, sigmodontinae) no Rio Grande do Sul, Brasil

Abstract: AbstrAct

Cited by 15 publications

References 23 publications

Morphological variation in the appendicular skeleton of atlantic forest sigmodontine rodents

Morphological variation in the appendicular skeleton of atlantic forest sigmodontine rodents

Ontogenetic allometry in the foot size of Oligoryzomys flavescens (Waterhouse, 1837) (Rodentia, Sigmodontinae)

Estudo morfométrico de Gliricola quadrisetosa Ewing, 1924 recuperado em Galea spixii Wagler, 1831

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