scholarly journals Cranial integration in the fire salamander, Salamandra salamandra (Caudata: Salamandridae)

2020 ◽  
Vol 130 (1) ◽  
pp. 178-194 ◽  
Author(s):  
Margot Bon ◽  
Carla Bardua ◽  
Anjali Goswami ◽  
Anne-Claire Fabre
Keyword(s):  
Influencing Factors ◽  
Significant Relationship ◽  
High Dimensional ◽  
Phenotypic Integration ◽  
Geometric Morphometric ◽  
Complex Interactions ◽  
Fire Salamander ◽  
Salamandra Salamandra ◽  
Static Level ◽  
Cranial Shape

Abstract Phenotypic integration and modularity are concepts that represent the pattern of connectivity of morphological structures within an organism. Integration describes the coordinated variation of traits, and analyses of these relationships among traits often reveals the presence of modules, sets of traits that are highly integrated but relatively independent of other traits. Phenotypic integration and modularity have been studied at both the evolutionary and static level across a variety of clades, although most studies thus far are focused on amniotes, and especially mammals. Using a high-dimensional geometric morphometric approach, we investigated the pattern of cranial integration and modularity of the Italian fire salamander (Salamandra salamandra giglioli). We recovered a highly modular pattern, but this pattern did not support either entirely developmental or functional hypotheses of cranial organisation, possibly reflecting complex interactions amongst multiple influencing factors. We found that size had no significant effect on cranial shape, and that morphological variance of individual modules had no significant relationship with degree of within-module integration. The pattern of cranial integration in the fire salamander is similar to that previously recovered for caecilians, with highly integrated jaw suspensorium and occipital regions, suggesting possible conservation of patterns across lissamphibians.

scholarly journals Influencing Factors of Social Anxiety and Emotional Maturity among Adolescents

2016 ◽  
Vol 3 (4) ◽  
Author(s):  
Dr. S Gayatridevi ◽  
Ms. Anu Vincent
Keyword(s):  
Social Anxiety ◽  
Influencing Factors ◽  
Family Size ◽  
Adolescent Girls ◽  
Significant Relationship ◽  
Psychological Tests ◽  
T Test ◽  
Emotional Maturity ◽  
Liebowitz Social Anxiety Scale

The current study deals with the emotional maturity and social anxiety among adolescents. One hundred and seventy subjects (Boys = 90, Girls = 80) from GRD College of Arts and Science, Coimbatore, were selected for the study. The Psychological Tests such as Case Study Schedule (Gayatridevi and Anu), Emotional Maturity Scale (Hemalatha) and Liebowitz Social Anxiety Scale (Michael R. Liebowitz) were administered to the subjects. The data was analyzed by using SPSS + PC package for t –test was computed. The results revealed that adolescent girls experienced more social anxiety than boys (M = 66.46). Gender and family size had no significant effect on emotional maturity. There was no significant relationship found between the emotional maturity and social anxiety.

scholarly journals Motivational factors and job satisfaction of employees in agriculture in the context of performance of agricultural companies in Slovakia

2020 ◽  
Vol 66 (No. 9) ◽  
pp. 402-412 ◽  
Author(s):  
Nadežda Jankelová ◽  
Zuzana Joniaková ◽  
Anita Romanová ◽  
Katarína Remeňová
Keyword(s):  
Job Satisfaction ◽  
Influencing Factors ◽  
Significant Relationship ◽  
Business Performance ◽  
Direct Relationship ◽  
Employee Motivation ◽  
Analysis Of Covariance ◽  
Mediation Model ◽  
Significant Extent ◽  
The Impact

The aim of our research is to identify how the effectiveness of motivation and job satisfaction of employees contribute to the success of agricultural companies in Slovakia. The research sample consists of 757 employees in agricultural companies in Slovakia. Baron and Kenny’s mediation model and regression ANCOVA (analysis of covariance) were also used. The hypothesis that the dependence of the business performance on the effectiveness of motivation of the employees is mediated by their job satisfaction has been confirmed. An important finding is that the direct relationship between the business performance of agricultural companies and the effectiveness of employee motivation is not significant. However, the variable that transmits this effect, respectively mediates the impact of the effectiveness of employee motivation on business performance, is the job satisfaction of employees. A significant relationship between the effectiveness of motivation was found mainly among financial motivators, which points to the problematic nature of this motivational setting. Significant influencing factors include age, education and job position. As the effectiveness of financial motivation and satisfaction was highest in these groups, it is possible to start applying new trends in employee remuneration to other groups that have not shown such a connection to such a significant extent.

scholarly journals Phylogenetic Comparative Methods and the Evolution of Multivariate Phenotypes

2019 ◽  
Vol 50 (1) ◽  
pp. 405-425 ◽  
Author(s):  
Dean C. Adams ◽  
Michael L. Collyer
Keyword(s):  
Phylogenetic Analysis ◽  
Evolutionary Biology ◽  
Generalized Least Squares ◽  
Comparative Methods ◽  
High Dimensional ◽  
Phenotypic Integration ◽  
Phylogenetic Comparative Methods ◽  
Evolutionary Trends ◽  
Phenotype Space ◽  
Multivariate Phenotypes

Evolutionary biology is multivariate, and advances in phylogenetic comparative methods for multivariate phenotypes have surged to accommodate this fact. Evolutionary trends in multivariate phenotypes are derived from distances and directions between species in a multivariate phenotype space. For these patterns to be interpretable, phenotypes should be characterized by traits in commensurate units and scale. Visualizing such trends, as is achieved with phylomorphospaces, should continue to play a prominent role in macroevolutionary analyses. Evaluating phylogenetic generalized least squares (PGLS) models (e.g., phylogenetic analysis of variance and regression) is valuable, but using parametric procedures is limited to only a few phenotypic variables. In contrast, nonparametric, permutation-based PGLS methods provide a flexible alternative and are thus preferred for high-dimensional multivariate phenotypes. Permutation-based methods for evaluating covariation within multivariate phenotypes are also well established and can test evolutionary trends in phenotypic integration. However, comparing evolutionary rates and modes in multivariate phenotypes remains an important area of future development.

scholarly journals Heterochronic Shifts Mediate Ecomorphological Convergence in Skull Shape of Microcephalic Sea Snakes

2019 ◽  
Vol 59 (3) ◽  
pp. 616-624 ◽  
Author(s):  
Emma Sherratt ◽  
Kate L Sanders ◽  
Amy Watson ◽  
Mark N Hutchinson ◽  
Michael S Y Lee ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Shape Variation ◽  
Micro Computed Tomography ◽  
Trophic Specialization ◽  
Evolutionary Patterns ◽  
Dietary Specialization ◽  
Geometric Morphometric ◽  
Sea Snakes ◽  
Morphometric Methods ◽  
Cranial Shape

Abstract Morphological variation among the viviparous sea snakes (Hydrophiinae), a clade of fully aquatic elapid snakes, includes an extreme “microcephalic” ecomorph that has a very small head atop a narrow forebody, while the hind body is much thicker (up to three times the forebody girth). Previous research has demonstrated that this morphology has evolved at least nine times as a consequence of dietary specialization on burrowing eels, and has also examined morphological changes to the vertebral column underlying this body shape. The question addressed in this study is what happens to the skull during this extreme evolutionary change? Here we use X-ray micro-computed tomography and geometric morphometric methods to characterize cranial shape variation in 30 species of sea snakes. We investigate ontogenetic and evolutionary patterns of cranial shape diversity to understand whether cranial shape is predicted by dietary specialization, and examine whether cranial shape of microcephalic species may be a result of heterochronic processes. We show that the diminutive cranial size of microcephalic species has a convergent shape that is correlated with trophic specialization to burrowing prey. Furthermore, their cranial shape is predictable for their size and very similar to that of juvenile individuals of closely related but non-microcephalic sea snakes. Our findings suggest that heterochronic changes (resulting in pedomorphosis) have driven cranial shape convergence in response to dietary specializations in sea snakes.

scholarly journals Ecomorphometric analysis of diversity in cranial shape of pygopodid geckos

2021 ◽  
Author(s):  
George P Gurgis ◽  
Juan D Daza ◽  
Ian G Brennan ◽  
Mark Hutchinson ◽  
Aaron M Bauer ◽  
...  
Keyword(s):  
Small Sample Size ◽  
Taxonomic Diversity ◽  
Small Sample ◽  
Cranial Morphology ◽  
Level Variation ◽  
Generic Level ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Components Analysis ◽  
Cranial Shape

Abstract Pygopodids are elongate, functionally limbless geckos found throughout Australia. The clade presents low taxonomic diversity (∼45 spp.), but a variety of cranial morphologies, habitat use, and locomotor abilities that vary between and within genera. In order to assess potential relationships between cranial morphology and ecology, CT scans of 29 species were used for 3D geometric morphometric analysis. A combination of 24 static landmarks and 20 sliding semi-landmarks were subjected to Generalized Procrustes Alignment. Disparity in cranial shape was visualized through Principal Components Analysis, and a MANOVA was used to test for an association between shape, habitat, and diet. A subset of 27 species with well-resolved phylogenetic relationships was used to generate a phylomorphospace and conduct phylogeny-corrected MANOVA. Similar analyses were done solely on Aprasia taxa to explore species-level variation. Most of the variation across pygopodids was described by PC1 (54%: cranial roof width, parabasisphenoid and occipital length), PC2 (12%: snout elongation and braincase width), and PC3 (6%: elongation and shape of the palate and rostrum). Without phylogenetic correction, both habitat and diet were significant influencers of variation in cranial morphology. However, in the phylogeny-corrected MANOVA, habitat remained weakly significant, but not diet, which can be explained by generic-level differences in ecology rather than among species. Our results demonstrate that at higher levels, phylogeny has a strong effect on morphology, but that influence may be due to small sample size when comparing genera. However, because some closely related taxa occupy distant regions of morphospace, diverging diets and use of fossorial habitats may contribute to variation seen in these geckos.

scholarly journals Ultrasonography: a method used for pregnancy imaging of the fire salamander (Salamandra salamandra)

2016 ◽  
Vol 19 (4) ◽  
pp. 715-722
Author(s):  
A. Najbar ◽  
Z. Kiełbowicz ◽  
J. Szymczak ◽  
M. Ogielska
Keyword(s):  
Veterinary Medicine ◽  
Ultrasound Imaging ◽  
Length Measurements ◽  
Fire Salamander ◽  
Minimum Number ◽  
Salamandra Salamandra ◽  
Gravid Females ◽  
Lower Silesia ◽  
In Pregnancy

Abstract Ultrasound imaging has more frequently been used in veterinary medicine of amphibians and reptiles. In this study, we have verified the usefulness of ultrasound imaging in pregnancy determination of the fire salamander Salamandra salamandra. We have also undertaken to estimate the number of larvae and their developmental stage directly in the oviducts. Three gravid females from Lower Silesia (southern Poland) were examined. Due to the small size of the scanned animals, and the particular arrangement of embryos in the oviducts and ultrasound beams dispersal, the method proved to be inaccurate. Therefore, the minimum number of well-visualized larvae was determined. The maximum number of larvae was established on the basis of the visible fragments of embryos. After birth, we found that the number of larvae born was included in the „min-max” range in only one case. In the remaining two salamanders the number of larvae was higher than estimated in 3 to 7 individuals. The results showed that ultrasound imaging allows the minimum number of larvae in salamander; oviducts to be specified. However, total length measurements were possible only for single and clearly visible embryos.

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