scholarly journals No Directional Scapular Asymmetry among Tamarines of the Genus Saguinus (Primates: Callitrichidae)

2020 ◽  
pp. 7-13
Author(s):  
P. M. Parés- Casanova ◽  
J. F. Vélez- García
Keyword(s):  
Fluctuating Asymmetry ◽  
Lateral Surface ◽  
The Other ◽  
Directional Asymmetry ◽  
Geometric Morphometric ◽  
Terrestrial Locomotion ◽  
Developmental Variation ◽  
Morphometric Methods ◽  
Perfect Symmetry ◽  
Left Scapula

Bilateral asymmetry is defined as a deviation of a whole organism or a part of it from a perfect symmetry, and different categories can be recognized. One is the fluctuating asymmetry, defined as the random developmental variation of a trait (or character) that is expected to be perfectly symmetrical on average, and the other one is directional asymmetry, which occurs when one of the sides shows stronger morphological structures or marks than the other. The aim of this study was to determine the kind of scapula asymmetry in Saguinus scapulae. On lateral surface of each right and left scapula, a set of 5 landmarks and 3 curves with semi-landmarks along the margins, on a sample of 16 pairs from different Saguinus species, were considered. Asymmetries (fluctuating and directional) on size and shape of the scapulae were analysed by means of geometric morphometric methods. Directional asymmetry was not detected, demonstrating no side scapular shape bias. The absence of significant directional asymmetry may indicate a similar contralateral pattern of employment of the shoulder, at least for one-arm vertical suspension, as it needs stronger forces than those for terrestrial locomotion and thus would cause more asymmetry in case side loadings were different. To our knowledge, this is the first investigation on the symmetrical/asymmetrical nature of scapulae in Saguinus. Our findings increase knowledge and understanding of humeral joint and arboreal locomotion in primates.

scholarly journals Marked Directional Skull Asymmetry in the Araucan Horse

VCOT Open ◽  
2020 ◽  
Vol 03 (01) ◽  
pp. e11-e18 ◽  
Author(s):  
Pere M. Parés-Casanova ◽  
René Alejandro Crosby-Granados ◽  
Fabián Muñoz ◽  
Arcesio Salamanca-Carreño
Keyword(s):  
Individual Development ◽  
Directional Asymmetry ◽  
Geometric Morphometric ◽  
Rightward Shift ◽  
Developmental Variation ◽  
Multiple Factors ◽  
Dorsal Aspect ◽  
Morphometric Methods ◽  
Perfect Symmetry ◽  
Masticatory Biomechanics

Abstract Background Deviations from the perfect symmetry of normally bilateral symmetrical characters occur during individual development due to the influence of multiple factors. Fluctuating asymmetry (FA) is the random developmental variation of a trait (or character) that is perfectly symmetrical, on average, across a population. Directional asymmetry (DA) occurs when one side of the pair of body sides is strongly more marked. Objective We investigated the presence and level of skull FA and DA in the Araucan horse, a breed from East Colombia. Study Design A sample of 21 skulls belonging to adult animals was studied by means of standard geometric–morphometric methods using 16 landmarks on the dorsal aspect of the crania. Results Measurements showed a significant DA with a consistent rightward shift of the splanchnocrania. Conclusions The results of this study raise questions about the influence of masticatory biomechanics on the asymmetric development of the skull, and also about how management and ingesta-specific properties (such as abrasiveness) may influence this asymmetry.

scholarly journals Side Differences in the Skull of Sheep: An Assessment by Geometric Morphometrics

2020 ◽  
pp. 1-7
Author(s):  
P. M. Parés-Casanova ◽  
A. Tolić ◽  
R. Carnicero
Keyword(s):  
Fluctuating Asymmetry ◽  
Genetic Factors ◽  
Bilateral Symmetry ◽  
Directional Asymmetry ◽  
Two Dimensional ◽  
Geometric Morphometric ◽  
Dorsal Aspect ◽  
Morphometric Methods ◽  
Muscular Function ◽  
External Stimuli

Effects of perturbations during development can be due to environmental and/or genetic factors, resulting in increased developmental instability which in turn can be expressed as fluctuating asymmetry (FA), defined as the non-directional deviation (right-left differences) from bilateral symmetry. However, other asymmetry types can appear, such as and directional asymmetry (DA), characterized by a distribution skewed to one side (right or left) at the, which is originated as a response to external stimuli that affect differentially on both sides of the organism. In order to describe asymmetric patterns in the ovine skull, we studied 165 specimens from animals belonging to the sheep breed “Navarra” from North Spain, using geometric morphometric methods. On digital pictures, we analyzed two midline and 8 bilateral two-dimensional landmarks on skull dorsal aspect. Results showed that FA accounted for a reduced amount of total variation, while DA explained most of it. We suggest that the presence of side differences due to lateralized muscular function (mastication) is the most important factor in skull asymmetry. Obtained results should provide a basis for relating asymmetries to the mechanics of cranial skeletum in sheep.

scholarly journals Towards More Realistic Leaf Shapes in Functional-Structural Plant Models

Symmetry ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 278 ◽  
Author(s):  
Dominik Schmidt ◽  
Katrin Kahlen
Keyword(s):  
Fluctuating Asymmetry ◽  
Leaf Shape ◽  
Three Dimensional ◽  
Directional Asymmetry ◽  
The Novel ◽  
Shape Model ◽  
Plant Model ◽  
Virtual Plant ◽  
Perfect Symmetry

Fluctuating asymmetry in plant leaves is a widely used measure in geometric morphometrics for assessing random deviations from perfect symmetry. In this study, we considered the concept of fluctuating asymmetry to improve the prototype leaf shape of the functional-structural plant model L-Cucumber. The overall objective was to provide a realistic geometric representation of the leaves for the light sensitive plant reactions in the virtual plant model. Based on three-dimensional data from several hundred in situ digitized cucumber leaves comparisons of model leaves and measurements were conducted. Robust Bayesian comparison of groups was used to assess statistical differences between leaf halves while respecting fluctuating asymmetries. Results indicated almost no directional asymmetry in leaves comparing different distances from the prototype while detecting systematic deviations shared by both halves. This information was successfully included in an improved leaf prototype and implemented in the virtual plant model L-Cucumber. Comparative virtual plant simulations revealed a slight improvement in plant internode development against experimental data using the novel leaf shape. Further studies can now focus on analyses of stress on the 3D-deformation of the leaf and the development of a dynamic leaf shape model.

scholarly journals Skull asymmetries in wild boar (Sus scrofa LINNAEUS, 1758)

2019 ◽  
Vol 56 (1) ◽  
pp. e150704
Author(s):  
Pere M. Parés-Casanova
Keyword(s):  
Environmental Factors ◽  
Wild Boar ◽  
Sus Scrofa ◽  
Age Groups ◽  
The Other ◽  
Directional Asymmetry ◽  
Two Dimensional ◽  
Entire Sample ◽  
Perfect Symmetry ◽  
Left And Right

Organisms can develop different kinds of asymmetry when deviations from expected perfect symmetry occur. Among others are fluctuating asymmetry (FA) and directional asymmetry (DA). FA represents small random differences between corresponding parts on the left and right sides of an individual in bilaterally paired structures. It is thought that FA reflects an organism’s ability to cope with genetic and environmental stress during growth. DA occurs whenever one side on the plane of symmetry develops more than the other side, and has a genetic component. In this research, we examined the expression of morphological symmetry in 38 skulls of different age groups of wild boar (Sus scrofa), on their ventral aspect, using two-dimensional coordinates of 27 landmarks. Analyses showed the presence of significant FA and DA in the entire sample, detecting also distinctive differences between age groups. The obtained results show that the shape differences in different age groups could reasonably be a consequence of a response to environmental factors for FA and a masticatory lateralization for DA.

scholarly journals Existence of mandibular directional asymmetry in the European wild boar (Sus scrofa Linnaeus, 1758)

2014 ◽  
Vol 31 (04) ◽  
pp. 228-232
Author(s):  
P. Parés-Casanova
Keyword(s):  
Sus Scrofa ◽  
Age Groups ◽  
The Body ◽  
The Other ◽  
Directional Asymmetry ◽  
Asymmetric Structure ◽  
Dorsal Aspect ◽  
European Wild Boar ◽  
Perfect Symmetry ◽  
The Right

Abstract Introduction and material and methods. We studied a sample of 37 dentulous dry mandibles from European wild board (Sus scrofa) and compared both the right and left sides in their dorsal aspect. To study the influence of age, the samples were grouped according to dental status: “subadults” (erupting 3rd M, n=22) and “adults” (fully erupted 3rd M, n=15). Individual levels of asymmetry were analysed from x- and y-coordinates of the 16 landmarks on the dorsal aspect of the mandible. Results. The analysis separated directional asymmetry (one side of the body with a larger character value than the other) and fluctuating asymmetry (small random deviations from perfect symmetry), which were both found to be significant. Conclusion. The condylar ramus was the most asymmetric structure for both age groups.

scholarly journals Functional skull asymmetries in Carollia perspicillata (Phyllostomidae Gray, 1825: Carollinae)

2020 ◽  
Vol 64 (1) ◽  
pp. 37-42
Author(s):  
Pere M. Parés-Casanova ◽  
Gerard Otin
Keyword(s):  
Fluctuating Asymmetry ◽  
Directional Asymmetry ◽  
Functional Requirements ◽  
Carollia Perspicillata ◽  
Geometric Morphometric ◽  
Domestic Species ◽  
Cranial Asymmetry ◽  
Dorsal Aspect ◽  
Morphological Responses

Analysing asymmetry in wild or domestic species enables the evaluation of the morphological responses to functional requirements and/or stress. This report is a study of the cranial asymmetry of Seba's short-tailed bat Carollia perspicillata by means of geometric morphometric techniques. We studied three types of bilateral asymmetries -fluctuating asymmetry, directional asymmetry and antisymmetry- using 15 skull landmarks on dorsal aspect of 45 skulls of Carollia perspicillata (21 males and 24 females) from different localities in Colombia. Directional asymmetry appeared to be significant and clearly higher than fluctuating asymmetry, with the braincase presenting the larger variance. There were no differences between sexes. Echolocation has a great anatomical effect on the bat cranium, and this would explain detected asymmetry.

Carapace asymmetries in crabs

Crustaceana ◽  
2018 ◽  
Vol 91 (11) ◽  
pp. 1281-1290
Author(s):  
Federica Spani ◽  
Massimiliano Scalici
Keyword(s):  
Fluctuating Asymmetry ◽  
Statistical Analyses ◽  
Directional Asymmetry ◽  
Environmental Constraints ◽  
Soil Composition ◽  
Geometric Morphometric ◽  
The Right ◽  
Predatory Pressure

Abstract Through the geometric morphometric approach of the landmark-based method applied on adult right-handed specimens of Carcinus aestuarii, Liocarcinus depurator and Potamon fluviatile, statistical analyses showed significant outcomes for fluctuating asymmetry in the three studied species, and directional asymmetry only in P. fluviatile (that showed a less convex carapace shape on the right side, where larger chela occurred). Although these findings may be correlated to some environmental constraints, such as soil composition, refuge occurrence and predatory pressure, also other interpretations may be proposed.

scholarly journals Asymmetry patterns are associated with body size and somatic robustness among adult !Kung San and Kavango people

2019 ◽  
Vol 82 (1) ◽  
pp. 43-63 ◽  
Author(s):  
Sylvia Kirchengast
Keyword(s):  
Body Size ◽  
Fluctuating Asymmetry ◽  
Body Height ◽  
Somatic Growth ◽  
Distinct Pattern ◽  
Directional Asymmetry ◽  
Developmental Stress ◽  
Somatic Development ◽  
Perfect Symmetry ◽  
Hand Length

Abstract Asymmetry of bilateral anatomical structures is widely found in nature. Fluctuating asymmetry, i.e. mostly tiny random deviations from perfect symmetry in bilateral structures, is mainly interpreted within the framework of developmental instability. This interpretation is mainly due to the fact, that higher fluctuating asymmetry is often found in association with various pathological conditions but also from increased stress during somatic development. Directional asymmetry, in contrast, describes a distinct pattern of bilateral variation in a group of individuals, characterized by the tendency to find the larger side mainly at the same side for all individuals. This kind of asymmetry is mostly caused by behavioral lateralization. Somatic stress during development affect not only asymmetry patterns, it is has also an adverse effect on somatic growth. Therefore, the present study tested the hypothesis, that increased asymmetry is associated with decreased body height as well as postcranial length and robustness dimensions. The association patterns between fluctuating as well as directional asymmetry and parameters of somatic growth and robustness are analyzed among 236 !Kung San and 248 Kavango people of Namibia between the ages of 18 and 65 years. Fluctuating asymmetry was determined by ear length and ear breadth. Directional asymmetry was determined by hand length and hand breadth dimensions. Fluctuating as well as directional asymmetry correlated significantly negatively with body height and length dimensions, the correlations however, were weak. The results are interpreted as a corroboration of the theory that developmental stress may increase fluctuating asymmetry but on the other hand may decrease body size.

scholarly journals Nature, Nurture, and Noise: Developmental Instability, Fluctuating Asymmetry, and the Causes of Phenotypic Variation

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1204
Author(s):  
John H. Graham
Keyword(s):  
Fluctuating Asymmetry ◽  
Phenotypic Variation ◽  
Deterministic Chaos ◽  
Monozygotic Twins ◽  
Developmental Instability ◽  
Nonlinear Feedback ◽  
Developmental Variation ◽  
Sewall Wright ◽  
Developmental Noise ◽  
And Behavior

Phenotypic variation arises from genetic and environmental variation, as well as random aspects of development. The genetic (nature) and environmental (nurture) components of this variation have been appreciated since at least 1900. The random developmental component (noise) has taken longer for quantitative geneticists to appreciate. Here, I sketch the historical development of the concepts of random developmental noise and developmental instability, and its quantification via fluctuating asymmetry. The unsung pioneers in this story are Hugo DeVries (fluctuating variation, 1909), C. H. Danforth (random variation between monozygotic twins, 1919), and Sewall Wright (random developmental variation in piebald guinea pigs, 1920). The first pioneering study of fluctuating asymmetry, by Sumner and Huestis in 1921, is seldom mentioned, possibly because it failed to connect the observed random asymmetry with random developmental variation. This early work was then synthesized by Boris Astaurov in 1930 and Wilhelm Ludwig in 1932, and then popularized by Drosophila geneticists beginning with Kenneth Mather in 1953. Population phenogeneticists are still trying to understand the origins and behavior of random developmental variation. Some of the developmental noise represents true stochastic behavior of molecules and cells, while some represents deterministic chaos, nonlinear feedback, and symmetry breaking.

scholarly journals Arothron: An R package for geometric morphometric methods and virtual anthropology applications

2021 ◽  
Author(s):  
Profico Antonio ◽  
Buzi Costantino ◽  
Castiglione Silvia ◽  
Melchionna Marina ◽  
Piras Paolo ◽  
...  
Keyword(s):  
R Package ◽  
Geometric Morphometric ◽  
Morphometric Methods ◽  
Virtual Anthropology
Sign in / Sign up

Export Citation Format

Share Document