Journal articles on the topic 'Shape morphology analyses'
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1
Bond, Jason E., and David A. Beamer. "A morphometric analysis of mygalomorph spider carapace shape and its efficacy as a phylogenetic character (Araneae)." Invertebrate Systematics 20, no. 1 (2006): 1. http://dx.doi.org/10.1071/is05041.
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Shape features are often used as characters in cladistic analyses, yet states of these characters are seldom delineated in an objective, repeatable fashion. Carapace shape is one such character that is often used in analyses of mygalomorph spider relationships. For example, most analyses have used cephalic region morphology (e.g. steeply arched v. flat or sloping) as a key feature that delineates some major clades. In practice, carapace shapes at the extremes are relatively easy to identify; however, intermediate carapace shapes have proven to be much more difficult to objectively score in one of three shape categories. In this study, carapace shape is used as an exemplar characteristic to evaluate the utility of shape features in phylogenetic analyses and to evaluate our ability to effectively score discrete character states. Carapaces from 178 spider specimens sampled across 13 of the 15 nominal mygalomorph families were digitally photographed and their outlines were traced and pseudo-landmarks plotted. An elliptical Fourier analysis was then employed in an attempt to both delineate and assess character states. It is concluded that landmark analyses are inappropriate for carapace shape delineation as a result of difficulties in scoring precision and, thus, outline analyses are the preferred method given the morphology. Carapace shape is not a very useful character for broad-level systematic studies of mygalomorph relationships owing to the variable nature of the feature and our inability to detect discrete discernable shapes.
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SWISHER, ROBERT E., and JIH-PAI LIN. "A geometric morphometric analysis of Arachnoides placenta (Echinoidea: Clypeasteroida): An examination of ontogenetic development and morphological variation." Zoosymposia 15, no. 1 (October 21, 2019): 159–71. http://dx.doi.org/10.11646/zoosymposia.15.1.18.
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Irregular echinoids, particularly clypeasteroids or “sand dollars”, have obtained highly adaptive morphologies suited to their life habitats. Specimens (n = 26) of a clypeasteroid echinoid Arachnoides placenta were examined to understand how these adaptive morphologies were ontogenetically and developmentally obtained. Ontogenetically, early post-larval juvenile specimens have a pentagonal morphologic outline (known as ambitus) that shifts to a circular or a sub-circular morphology observed in the largest adult specimens. Circular morphology appears optimized for the adult life habitat or niche. Both landmark and semilandmark geometric morphometric methodologies were applied to quantify shape change, ontogenetic variation, and developmental morphology in A. placenta. Ambitus change is concentrated along the interambulacral regions with broader curvature variations occurring across both ambulacral and interambulacral regions. Circular adult morphology was a result of non-isometric shape change concentrated anteriorly with minor variation around posterior margin/periproctal furrow. Interior morphologic change of the petaloids and periproct was also quantified, mainly impacting posterior outline morphology. Minimal deformation of the basicoronal plates was detected, indicating stability during ontogeny. Results indicated that complex, non-isometric allometric shape change, both along the ambitus and interiorly, is required to morph from a pentagonal outline in post-larval juveniles to a circular or sub-circular ambitus morphology in adults. This analysis demonstrates the advantages of both landmark and semilandmark geometric morphometric analyses for quantifying developmental change and shape variation in Clypeasteroida.
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Suzuki, Kazumasa, Yasuaki Tokudome, Hiroshi Tsuda, and Masahide Takahashi. "Morphology control of BiFeO3aggregatesviahydrothermal synthesis." Journal of Applied Crystallography 49, no. 1 (February 1, 2016): 168–74. http://dx.doi.org/10.1107/s1600576715023845.
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The assembly of crystalline building units with specific shape-derived properties into aggregates is often required to broaden their practical applications because the properties of the building units can be fully integrated and used in the aggregates owing to their orientation. Herein, morphology-controlled BiFeO3aggregates composed of oriented crystalline building units were fabricatedviaa hydrothermal process without any additives, and the effects of the supersaturation conditions on the aggregation state were investigated. The supersaturation condition, controlled by varying the KOH concentration, was found to affect the shape of the crystalline building units. For lower supersaturation conditions, the morphology of the aggregates was found to be closely related to the shape of the fundamental building units, and the results indicated that oriented attachment occurred between specific crystal faces of the building units. Under a high supersaturation condition, the morphology of the aggregate did not reflect the shape of the building units and a monodispersed spherical aggregate was obtained. Further, the internal microstructures of the aggregates changed from homogeneous and dense to sparse core and dense shell structures with an increasing supersaturation condition. The formation mechanism of these morphology-controlled aggregates is discussed using microstructure analyses. The present approach to control the morphology of aggregates using the shape of the building units and aggregation kinetics could also be applicable for other microcrystalline aggregated systems in addition to BiFeO3.
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Kozitzky, Emma. "The impact of hybridization on upper first molar shape in robust capuchins (Sapajus nigritus x S. libidinosus)." Dental Anthropology Journal 34, no. 1 (January 12, 2021): 13–34. http://dx.doi.org/10.26575/daj.v34i1.316.
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To better understand the impact of hybridization on development and morphology, I analyze an understudied phenotype in hybrid morphology research: tooth shape. I apply a 2D geometric morphometric approach to compare variation in first upper molar cusp tip positions and crown outline shape among 31 crested capuchins (Sapajus nigritus), 37 bearded capuchins (S. libidinosus), and 44 hybrids (S. nigritus x S. libidinosus). A principal components analysis shows that group membership accounts for a significantly greater proportion of variance along the first major axis of M1 shape variation than does allometry. While most hybrids have S. nigritus-like M1s, several possess a transgressive M1 shape not observed in either parental species. Procrustes distances are greater in hybrids compared to the parental capuchins, and two-block partial least squares analyses show that hybrids exhibit weaker integration between cusp tip positions and crown outline shape. These results demonstrate that hybridization generates novel M1 shapes and support the hypothesis that destabilized development results in elevated phenotypic variance in hybrids. Further studies of dental shape in hybrid primates will generate important data for on-going efforts to detect potential hybrids in the hominin fossil record and to understand the evolutionary outcomes of anthropogenic hybridization.
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Mahé, Kélig, Djamila Ider, Andrea Massaro, Oussama Hamed, Alba Jurado-Ruzafa, Patrícia Gonçalves, Aikaterini Anastasopoulou, et al. "Directional bilateral asymmetry in otolith morphology may affect fish stock discrimination based on otolith shape analysis." ICES Journal of Marine Science 76, no. 1 (November 15, 2018): 232–43. http://dx.doi.org/10.1093/icesjms/fsy163.
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Abstract Otolith shape analysis is an efficient fish stock identification tool. However, most applications used left and right otoliths or only one of them arbitrarily chosen without testing for biases resulting from potential directional bilateral asymmetry (DA) in otolith shape, i.e. a unimodal population-level deviation form bilateral symmetry between right and left otolith shapes. In this study, 560 bogues (Boops boops) were sampled from 11 geographical locations from the Canary Islands to the Aegean Sea and elliptical Fourier descriptors were used to describe their otoliths’ shape. First, a significant otolith DA was observed at the global scale with an average amplitude of 2.77%. However, at the scale of sampling locations, DA was not always significant and varied in amplitude and direction. Second, population structure was investigated using the shape of either right otoliths or left otoliths or both together. Analyses based on right otoliths or both otoliths together, suggested three stock units: a North-Western Mediterranean Sea stock, an Eastern Mediterranean Sea stock, and a Central-Eastern Atlantic Ocean and South-Western Mediterranean Sea stock. In contrast, no coherent geographical pattern was found based on left otoliths. Our results highlight the importance of accounting for potential otolith DA in otolith shape-based stock identification.
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Cooper, W. James, and Scott J. Steppan. "Developmental constraint on the evolution of marsupial forelimb morphology." Australian Journal of Zoology 58, no. 1 (2010): 1. http://dx.doi.org/10.1071/zo09102.
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Compared with the placental mammals, marsupials are born at an almost embryonic stage, but nearly all of these neonates immediately climb or crawl to one of their mother’s teats using precociously developed forelimbs. Marsupial adults also exhibit limited forelimb shape diversity relative to the members of their sister group. That the functional requirements of this natal climb have imposed a developmental constraint on marsupial forelimb evolution represents a compelling and widely accepted hypothesis, yet its resulting predictions for the comparative patterns of mammal limb shape diversity have never been tested. In order to perform such tests we conducted extensive taxonomic sampling of mammal limb morphology (including fossil specimens), and then examined these data using morphometric methods, non-parametric analyses of anatomical disparity, and phylogenetic comparative analyses of evolutionary rates. Our results strongly support the constraint hypothesis, and indicate that the highly significant differences between marsupial and placental forelimb shape diversity has been strongly influenced by different rates of morphological evolution among the distal forelimb elements in these two important mammal lineages.
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Yousefkhani, Seyyed Saeed Hosseinian, Hossein Nabizadeh, and L. Lee Grismer. "Ecomorphological differences among forest and rock dwelling species of Darevskia Arribas, 1999 (Squamata, Lacertide) in the Elburz Mountains, Iran." Herpetozoa 35 (December 21, 2022): 245–56. http://dx.doi.org/10.3897/herpetozoa.35.e95257.
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Ecological pressure is the major driver of morphological adaptation. Different habitat preferences even among closely related species, often result in the evolution of different body shapes. In the present study, we employed geometric morphometric and principal component analyses (PCA) to compare body shape and head plate morphology among seven species in the genus Darevskia Arribas, 1999 from the Elburz Mountains, Iran that occur in either rocky or forested habitats. The geometric morphometric analysis and the PCA of meristic characters recovered a wide degree of overlap between the rock and forest dwelling species. The PCA of the morphometric characters showed wide separation among the rock and forest dwelling species as well as among some of the rock dwelling species. These results strongly suggest that body shape is correlated with the habitat type whereas head plate morphology and scale meristics are not. Furthermore, the results suggest that the rock dwelling species may be occupying and navigating their microhabitat in different ways. Ecological observations are needed to test this hypothesis.
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Goswami, Anjali, Akinobu Watanabe, Ryan N. Felice, Carla Bardua, Anne-Claire Fabre, and P. David Polly. "High-Density Morphometric Analysis of Shape and Integration: The Good, the Bad, and the Not-Really-a-Problem." Integrative and Comparative Biology 59, no. 3 (June 27, 2019): 669–83. http://dx.doi.org/10.1093/icb/icz120.
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Abstract The field of comparative morphology has entered a new phase with the rapid generation of high-resolution three-dimensional (3D) data. With freely available 3D data of thousands of species, methods for quantifying morphology that harness this rich phenotypic information are quickly emerging. Among these techniques, high-density geometric morphometric approaches provide a powerful and versatile framework to robustly characterize shape and phenotypic integration, the covariances among morphological traits. These methods are particularly useful for analyses of complex structures and across disparate taxa, which may share few landmarks of unambiguous homology. However, high-density geometric morphometrics also brings challenges, for example, with statistical, but not biological, covariances imposed by placement and sliding of semilandmarks and registration methods such as Procrustes superimposition. Here, we present simulations and case studies of high-density datasets for squamates, birds, and caecilians that exemplify the promise and challenges of high-dimensional analyses of phenotypic integration and modularity. We assess: (1) the relative merits of “big” high-density geometric morphometrics data over traditional shape data; (2) the impact of Procrustes superimposition on analyses of integration and modularity; and (3) differences in patterns of integration between analyses using high-density geometric morphometrics and those using discrete landmarks. We demonstrate that for many skull regions, 20–30 landmarks and/or semilandmarks are needed to accurately characterize their shape variation, and landmark-only analyses do a particularly poor job of capturing shape variation in vault and rostrum bones. Procrustes superimposition can mask modularity, especially when landmarks covary in parallel directions, but this effect decreases with more biologically complex covariance patterns. The directional effect of landmark variation on the position of the centroid affects recovery of covariance patterns more than landmark number does. Landmark-only and landmark-plus-sliding-semilandmark analyses of integration are generally congruent in overall pattern of integration, but landmark-only analyses tend to show higher integration between adjacent bones, especially when landmarks placed on the sutures between bones introduces a boundary bias. Allometry may be a stronger influence on patterns of integration in landmark-only analyses, which show stronger integration prior to removal of allometric effects compared to analyses including semilandmarks. High-density geometric morphometrics has its challenges and drawbacks, but our analyses of simulated and empirical datasets demonstrate that these potential issues are unlikely to obscure genuine biological signal. Rather, high-density geometric morphometric data exceed traditional landmark-based methods in characterization of morphology and allow more nuanced comparisons across disparate taxa. Combined with the rapid increases in 3D data availability, high-density morphometric approaches have immense potential to propel a new class of studies of comparative morphology and phenotypic integration.
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Szmańda, Jacek Bogusław, and Karol Witkowski. "Morphometric Parameters of Krumbein Grain Shape Charts—A Critical Approach in Light of the Automatic Grain Shape Image Analysis." Minerals 11, no. 9 (August 28, 2021): 937. http://dx.doi.org/10.3390/min11090937.
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Grain-shape analyses are essential in geological research because they provide the basis for genetic interpretations, including sedimentation conditions. The methods of visual evaluation used so far have been subjective, time-consuming and labour intensive. Automatic particle image analysis, including the methods used by the Morphology G3SE device, open up the possibility of mass and objective roundness analysis of mineral and organic particles. The article presents the results of measurements for the grain scale proposed by Krumbein in 1941, as this scale has been used in numerous sedimentological studies. The standard shapes were analysed using four parameters: High Sensitivity (HS) Circularity, Convexity, Solidity and Aspect Ratio. In the discussion, both the results and the grain-shape standards were critically assessed. The most important trends in the distribution of morphometric parameters of the scale are shown. On this basis, it was found that it is impossible to determine the parameter boundary values that would distinguish each class of grain roundness proposed by Krumbein. The conclusions propose criteria for the automatic differentiation of angular, subrounded and rounded grains, which could be a basis for describing the shape of mineral particles.
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Hernández-L., N., Á. R. Barragán, S. Dupas, J. F. Silvain, and O. Dangles. "Wing shape variations in an invasive moth are related to sexual dimorphism and altitude." Bulletin of Entomological Research 100, no. 5 (January 27, 2010): 529–41. http://dx.doi.org/10.1017/s000748530999054x.
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AbstractWing morphology has great importance in a wide variety of aspects of an insect's life. Here, we use a geometric morphometric approach to test the hypothesis that variation, in insect wing morphology patterns, occurs between sexes and along altitudinal gradients for invasive species, despite their recent association to this environment. We explored the variation in wing morphology between 12 invasive populations of the invasive potato pest, Tecia solanivora, at low and high altitude in the central highlands of Ecuador. After characterizing sexual dimorphism in wing shape, we investigated if moths at higher elevations differ in wing morphology from populations at lower altitudes. Results indicate wing shape and size differences between sexes and between altitudinal ranges. Females showed larger, wider wings than males, while high altitude moths showed larger, narrow-shaped wings by comparison to low-altitude moths. GLM analyses confirmed altitude was the only significant determinant of this gradient. Our study confirms a sexual dimorphism in size and wing shape for the potato moth. It also confirms and extends predictions of morphological changes with altitude to an invasive species, suggesting that wing morphology variation is an adapted response contributing to invasion success of the potato moth in mountainous landscapes. Ours is one of the first studies on the morphology of invasive insects and represents a valuable contribution to the study of insect invasions because it both offers empirical support to previous genetic studies on T. solanivora as well as proving broader insight into the mechanisms behind morphological evolution of a recently introduced pest.
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Morón-García, Odín, Gina A. Garzón-Martínez, M. J. Pilar Martínez-Martín, Jason Brook, Fiona M. K. Corke, John H. Doonan, and Anyela V. Camargo Rodríguez. "Genetic architecture of variation in Arabidopsis thaliana rosettes." PLOS ONE 17, no. 2 (February 16, 2022): e0263985. http://dx.doi.org/10.1371/journal.pone.0263985.
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Rosette morphology across Arabidopsis accessions exhibits considerable variation. Here we report a high-throughput phenotyping approach based on automatic image analysis to quantify rosette shape and dissect the underlying genetic architecture. Shape measurements of the rosettes in a core set of Recombinant Inbred Lines from an advanced mapping population (Multiparent Advanced Generation Inter-Cross or MAGIC) derived from inter-crossing 19 natural accessions. Image acquisition and analysis was scaled to extract geometric descriptors from time stamped images of growing rosettes. Shape analyses revealed heritable morphological variation at early juvenile stages and QTL mapping resulted in over 116 chromosomal regions associated with trait variation within the population. Many QTL linked to variation in shape were located near genes related to hormonal signalling and signal transduction pathways while others are involved in shade avoidance and transition to flowering. Our results suggest rosette shape arises from modular integration of sub-organ morphologies and can be considered a functional trait subjected to selective pressures of subsequent morphological traits. On an applied aspect, QTLs found will be candidates for further research on plant architecture.
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Rocha-Barbosa, O., JSL Bernardo, MFC Loguercio, TRO Freitas, JR Santos-Mallet, and CJ Bidau. "Penial morphology in three species of Brazilian Tuco-tucos, Ctenomys torquatus, C. minutus, and C. flamarioni (Rodentia: Ctenomyidae)." Brazilian Journal of Biology 73, no. 1 (February 2013): 201–9. http://dx.doi.org/10.1590/s1519-69842013000100022.
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The present study analyses the glans penis and baculum morphology of three Brazilian tuco-tucos, Ctenomys torquatus Lichtenstein, 1830, Ctenomys minutus Nehring, 1887 and Ctenomys flamarioni Travi, 1981, in order to identify possible variations and understand some more about this taxonomically complex group. We used fixed penis from 15 previously listed adult specimens. For a more detailed baculum analysis, the penis underwent dissection and diaphanisation, whereas to analyse the glans penis surface we used Scanning Electron Microscopy (SEM). Results showed striking differences in baculum morphology among the three species. While C. minutus have a particular V-shaped proximal baculum tip, C. flamarioni baculum is thin throughout the shaft with rounded proximal and distal tips. Ctenomys torquatus have a shorter and larger baculum, similar to what has previously been described for the species. Glans penis surface microstructure analyses also revealed inter-specific differences, with penial spines varying in shape, size and, especially density. Although C. torquatus has a relatively small penis, it has the largest penial spine density, which suggests a more complex penial ornamentation in this species.
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Baeckens, Simon, Charlotte Goeyers, and Raoul Van Damme. "Convergent Evolution of Claw Shape in a Transcontinental Lizard Radiation." Integrative and Comparative Biology 60, no. 1 (November 7, 2019): 10–23. http://dx.doi.org/10.1093/icb/icz151.
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Abstract Species occupying similar selective environments often share similar phenotypes as the result of natural selection. Recent discoveries, however, have led to the understanding that phenotypes may also converge for other reasons than recurring selection. We argue that the vertebrate claw system constitutes a promising but understudied model system for testing the adaptive nature of phenotypic, functional, and genetic convergence. In this study, we combine basic morphometrics and advanced techniques in form analysis to examine claw shape divergence in a transcontinental lizard radiation (Lacertidae). We find substantial interspecific variation in claw morphology and phylogenetic comparative statistics reveal a strong correlation with structural habitat use: ground-dwelling species living in open areas are equipped with long, thick, weakly curved, slender-bodied claws, whereas climbing species carry high, short, strongly curved, full-bodied claws. Species occupying densely vegetated habitats tend to carry intermediately shaped claws. Evolutionary models suggest that claw shape evolves toward multiple adaptive peaks, with structural habitat use pulling species toward a specific selective optimum. Contrary to findings in several other vertebrate taxa, our analyses indicate that environmental pressures, not phylogenetic relatedness, drive convergent evolution of similarly shaped claws in lacertids. Overall, our study suggests that lacertids independently evolved similarly shaped claws as an adaptation to similar structural environments in order to cope with the specific locomotory challenges posed by the habitat. Future biomechanical studies that link form and function in combination with genomic and development research will prove valuable in better understanding the adaptive significance of claw shape divergence.
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Gasparini, Arthur Stefanelli, Maurício Paulo Ferreira Fontes, Anderson Almeida Pacheco, and João Carlos Ker. "Gibbsite Crystallinity and Morphology in Ferralsols and Bauxites." Minerals 12, no. 11 (November 14, 2022): 1441. http://dx.doi.org/10.3390/min12111441.
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Gibbsite is a common mineral, present in several soil classes around the globe, especially in the tropical belt. It is also a key mineral in bauxite, the main natural source of aluminum. The occurrence of gibbsite in the soil greatly influences its physical and chemical characteristics. However, little is known about the important structural properties of this mineral, which determines how these characteristics will be expressed. In this work, we investigated the variation in the morphology and crystallinity of naturally occurring gibbsites from soils and bauxites. The crystallinity of the gibbsite was assessed using full width at half maximum (FWHM), mean crystallite dimensions (MCD), and deoxydylation temperature (DT) measurements. The results of these analyses were convergent, indicating a better crystallinity for gibbsites from the evaluated Amazon soils and bauxites, and worse crystallinity for the remaining soil samples. SEM analysis was used to assess the gibbsite morphology, and X-ray diffraction data were used to propose an orientation index for this mineral. The results indicated that there is little to no isomorphic substitution of Al by Fe in natural gibbsites, there is a prevalence of larger crystals, with a more laminar morphology, with orientation capability for the gibbsites of Amazon soils and bauxites, and smaller crystals tending to spherical shape for the other samples. These results suggest that natural gibbsite crystals of good crystallinity have large crystals with a laminar shape, while crystals of lower crystallinity present a smaller size and approximately an isodiametric shape.
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Srygley, Robert B. "Locomotor mimicry in Heliconius butterflies: contrast analyses of flight morphology and kinematics." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 354, no. 1380 (January 29, 1999): 203–14. http://dx.doi.org/10.1098/rstb.1999.0372.
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Müllerian mimicry is a mutualism involving the evolutionary convergence of colour patterns of prey on a warning signal to predators. Behavioural mimicry presumably adds complexity to the signal and makes it more difficult for Batesian mimics to parasitize it. To date, no one has quantified behavioural mimicry in Müllerian mimicry groups. However, morphological similarities among members of mimicry groups suggested that pitching oscillations of the body and wing–beat frequency (WBF) might converge with colour pattern. I compared the morphology and kinematics of four Heliconius species, which comprised two mimicry pairs. Because the mimics arose from two distinct lineages, the relative contributions of mimicry and phylogeny to variation in the species' morphologies and kinematics were examined. The positions of the centre of body mass and centre of wing mass and wing shape diverged among species within lineages, and converged among species within mimicry groups. WBF converged within mimicry groups, and it was coupled with body pitching frequency. However, body–pitching frequency was too variable to distinguish mimicry groups. Convergence in WBF may be due, at least in part, to biomechanical consequences of similarities in wing length, wing shape or the centre of wing mass among co–mimics. Nevertheless, convergence in WBF among passion–vine butterflies serves as the first evidence of behavioural mimicry in a mutualistic context.
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Chen, Yun, Jian Zhao, Qingyu Chen, and Jun Chen. "Simulation for Fitting the Bending Shape of Fruit Branches of Lycium barbarum Based on the Finite Element Method." Horticulturae 7, no. 11 (October 25, 2021): 434. http://dx.doi.org/10.3390/horticulturae7110434.
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The accurate modeling of wolfberry plant morphology is the basis for theoretical and simulation analyses of the wolfberry picking process. The curved shape of the fruit branches makes it challenging to model Lyciumbarbarum (wolfberry) plants. This paper establishes a three-dimensional model of the branches under no gravity through field measurements, and then assesses the morphology of the branches under gravity load, fruit load, and branch load using finite element simulation. An orthogonal rotation combination experiment determined the relationship between branch morphology, length, growth angle, and growth mode parameters. The p-values of the prediction model were 0.0001, 0.0067, and 0.0203, respectively. Finally, the bending shape of the actual branches was verified against the branches generated by the prediction model. The experimental results show that the prediction model accurately models the fruit-bearing branches of Lycium barbarum. This paper introduces a method to quickly predict the bending shape of fruit-bearing branches of Lycium barbarum, providing a theoretical basis for rapid modeling of the L. barbarum plant and a simulation analysis for its harvesting.
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Dyana Merline, J., and Reghunadhan Nair, C.P. "Nanoclay Modification of Shape Memory Polyurethane." Eurasian Chemico-Technological Journal 15, no. 4 (November 3, 2015): 327. http://dx.doi.org/10.18321/ectj239.
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Effect of nanoclay modification on the properties of polytetramethylene oxide-based polyurethane was examined. Nanoclay was dispersed in polyurethane wherein the clay content was varied from 1 to 5 wt.%. The nanocomposites were characterized by thermal, FTIR, XRD and thermo-mechanical analyses and their shape memory properties were evaluated. Morphology was examined by TEM analysis. Bending test<br />was adopted for the evaluation of shape memory property. Increase in clay content resulted an increase in transition temperature. Tensile strength and modulus increased proportional to nanoclay content. The elongation decreased with clay content. Intercalated structure of clay in the PU matrix was observed<br />from XRD studies, which was confirmed by TEM analysis. Modulus ratio showed a decreasing trend with nanoclay content. This resulted in decreased shape recovery characteristics. Highest shape recovery of 92% was observed for PU with 1 wt.% clay content. Moderate nanoclay leveling is conducive to deriving<br />mechanically stronger PU without loss of shape memory characteristics.
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Calderón-Acevedo, Camilo A., Miguel E. Rodríguez-Posada, and Nathan Muchhala. "Morphology and genetics concur that Anoura carishina is a synonym of Anoura latidens (Chiroptera, Glossophaginae)." Mammalia 85, no. 5 (April 26, 2021): 471–81. http://dx.doi.org/10.1515/mammalia-2020-0183.
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Abstract Anoura carishina was described based on cranial and dental morphology, but the original analyses did not include Anoura latidens, a similar species of Anoura. We used morphological, morphometric, and genetic analyses to evaluate the taxonomic identity of A. carishina. We performed a principal components analysis to evaluate the correspondence between morphological and taxonomic groups for 260 specimens of large-bodied Anoura (A. carishina, Anoura geoffroyi, A. latidens, and Anoura peruana), and statistically analyzed traits diagnostic for A. latidens, including (1) morphology of the third upper premolar (P4), (2) size of the second (P3) and third (P4) upper premolars, and (3) angle formed by the maxillary toothrows. We find that A. latidens and A. carishina are indistinguishable, and share several characters lacking in A. geoffroyi, including a P4 with triangular shape, an under-developed anterobasal cusp in the P3, a smaller braincase, and a shorter rostrum. Phylogenetic analyses using ultra-conserved elements infer that the holotype and two paratype specimens of A. carishina are paraphyletic and nested within A. latidens, while one paratype diagnosable by morphology as A. geoffroyi nests within A. geoffroyi samples. We demonstrate that A. carishina should be considered a junior synonym of A. latidens, updating the distribution of the latter.
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Lee, Changyoung, Jinki Kim, Ashwini M. Darshetkar, Ritesh Kumar Choudhary, Sang-Hong Park, Joongku Lee, and Sangho Choi. "Mericarp morphology of the tribe Selineae (Apiaceae, Apioideae) and its taxonomic implications in Korea." Bangladesh Journal of Plant Taxonomy 25, no. 2 (December 29, 2018): 175–86. http://dx.doi.org/10.3329/bjpt.v25i2.39524.
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Mericarp morphology of 24 taxa belonging to nine genera of the tribe Selineae (Family: Apiaceae) in Korea was studied by Scanning Electron Microscopy. UPGMA and NMDS analyses were performed based on 12 morphological characters. The mericarp surface characters like mericarp shape, rib number and shape, surface pattern, surface appendages and mericarp symmetry proved useful in distinguishing the genera of the tribe Selineae.
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Godinho, Ricardo Miguel, Cláudia Umbelino, and Célia Gonçalves. "Mesolithic and Chalcolithic Mandibular Morphology: Using Geometric Morphometrics to Reconstruct Incomplete Specimens and Analyse Morphology." Open Archaeology 8, no. 1 (January 1, 2022): 536–49. http://dx.doi.org/10.1515/opar-2022-0247.
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Abstract Human skeletal remains are routinely used to examine cultural and biological aspects of past populations. Yet, archaeological specimens are frequently fragmented/incomplete and so excluded from analyses. This leads to decreased sample sizes and to potentially biased results. Digital methods are now frequently used to restore/estimate the original morphology of fragmented/incomplete specimens. Such methods include 3D digitisation and Geometric Morphometrics (GM). The latter is also a solidly established method now to examine morphology. In this study, we use GM-based methods to estimate the original morphology of incomplete Mesolithic and Chalcolithic mandibles originating from present Portugal and perform ensuing morphological analyses. Because mandibular morphology is known to relate to population history and diet, we hypothesised the two samples would differ. Thirty-seven specimens (12 complete and 25 incomplete) were CT-scanned and landmarked. Originally complete specimens were used as reference to estimate the location of absent anatomical landmarks in incomplete specimens. As predicted, our results show shape differences between the two samples which are likely due to the compounded effect of contrasting population histories and diets.
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Doeschl, A. B., D. M. Green, C. T. Whittemore, C. P. Schofield, A. V. Fisher, and P. W. Knap. "The relationship between the body shape of living pigs and their carcass morphology and composition." Animal Science 79, no. 1 (April 2004): 73–83. http://dx.doi.org/10.1017/s1357729800054540.
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AbstractThe conformation, tissue composition, and chemical composition of three types of pigs, given food ad libitum and slaughtered over a nominal live weight range of 35 to 115 kg, was assessed in relation to data provided on the live animals by a visual image analysis (VIA) system. The pig types were named as ‘3⁄4 Landrace’, ‘1⁄2 Pietrain’, and ‘1⁄4 Meishan’ types, representing ‘attenuated’, ‘blocky’, and ‘flabby’ types. Three analyses of the shape, conformation and composition data were performed. First, the relationship between conformation and age/size was assessed using linear regression of logarithmically transformed VIA and carcass data. In relation to age, ‘1⁄2 Pietrain’ pigs were found by both VIA and carcass measurements to have the widest shoulders. Both analyses also found this type to have the widest ham, trunk, and shoulders in relation to body length across most of the body length range studied, although the greatest rate of increase in ham width in relation to body length was found in the ‘1/4 Meishan’ type pigs. Second, the relationship between composition and VIA shape was examined using linear regression of transformed and standardized data. Significant relationships were found between fat, lipid, muscle, and protein weight and VIA shape, although relationships were weaker for protein and muscle weight. For fat and lipid, the VIA shape measures from the trunk region proved the most informative, whereas the VIA ham measures proved the most informative for muscle and protein. Third, detrended measures of composition/conformation and shape were used to remove the effect of animal size from the data. Removal of the variation due to growth generally led to substantial decreases in the adjusted R2statistics and in the R2-like statistics for prediction. Although in the models without detrending, relative fat and lipid weight had been found most strongly correlated with VIA shape, relative muscle was found most strongly correlated with shape in the detrended data. This was considered to result from the low between-animal variation in the data set combined with greater across-weight variation in fat and lipid weights than muscle and protein weights in the data without trend removal. Future trials with greater between-animal variation imposed would allow more precise determination of the relationship between conformation and shape.
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White, Heather E., Julien Clavel, Abigail S. Tucker, and Anjali Goswami. "A comparison of metrics for quantifying cranial suture complexity." Journal of The Royal Society Interface 17, no. 171 (October 2020): 20200476. http://dx.doi.org/10.1098/rsif.2020.0476.
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Cranial sutures play critical roles in facilitating postnatal skull development and function. The diversity of function is reflected in the highly variable suture morphology and complexity. Suture complexity has seldom been studied, resulting in little consensus on the most appropriate approach for comparative, quantitative analyses. Here, we provide the first comprehensive comparison of current approaches for quantifying suture morphology, using a wide range of two-dimensional suture outlines across extinct and extant mammals ( n = 79). Five complexity metrics (sinuosity index (SI), suture complexity index (SCI), fractal dimension (FD) box counting, FD madogram and a windowed short-time Fourier transform with power spectrum density (PSD) calculation) were compared with each other and with the shape variation in the dataset. Analyses of suture shape demonstrate that the primary axis of variation captured attributes other than complexity, supporting the use of a complexity metric over raw shape data for sutural complexity analyses. Each approach captured different aspects of complexity. PSD successfully discriminates different sutural features, such as looping patterns and interdigitation amplitude and number, while SCI best-captured variation in interdigitation number alone. Therefore, future studies should consider the relevant attributes for their question when selecting a metric for comparative analysis of suture variation, function and evolution.
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Hussain, Adil, Daniel Potter, Muhammad Qasim Hayat, Sumaira Sahreen, and Syed Ali Imran Bokhari. "Pollen morphology and its systematic implication on some species of Artemisia L. from Gilgit-Baltistan Pakistan." Bangladesh Journal of Plant Taxonomy 26, no. 2 (December 23, 2019): 157–68. http://dx.doi.org/10.3329/bjpt.v26i2.44576.
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This study was accomplished to scrutinize the pollen morphology of 15 species of the genus Artemisia of the family Asteraceae from Gilgit-Baltistan region of Pakistan by means of scanning electron microscopy (SEM). Results revealed pollen grains of Artemisia species with tricolporate shape, and characterized by globular symmetry (ellipsoid ball shaped from equatorial side and three lobed rounds from polar view) with few exceptions. Additionally, the pollens are marked with reduced spinules on their surfaces which are diagnostic character for the genus Artemisia. In this study, seven micromorphological characters of pollen grains of 15 Artemisia species viz. shape of pollen, arrangement of spinules, exine sculpture, spinules base, equatorial width and polar length, were employed to construct a dendrogram following the consequential cluster analyses. In the dentrogram, four groups within the studied Artemisia species have been recognized. The pollen morphology of Artemisia could be a good taxonomic marker to cope with its taxonomic delimitations in combination with other floral and molecular attributes.
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Sudha Mattigatti. "Cone Beam Computed Tomography (Cbct) and Endodontic Microscopic Assessment of C-Shaped Canal Systems in Mandibular Second Molars." International Journal of Research in Pharmaceutical Sciences 11, no. 3 (July 23, 2020): 3999–4005. http://dx.doi.org/10.26452/ijrps.v11i3.2595.
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By knowing the anatomy of the tooth including root canal, dentists also have gathered physiologically anomalous requirements for effective root canal treatment. An exceptional morphology is present in the root canal system known as the C-shaped root network. A substantial volume of evidence already has come out on C-shaped root canal systems. The analysis provides an extensive description of root through root canals in the form of C. Characteristics of this exceptional morphology were studied mainly focused on macroscopic, microscopic and functional measurements including odontogenetic tooth shape analyses. To trying to clarify the clinical nature of C-shaped root canals, we sought to isolate them both. In addition to summarizing existing experiences, another of the objectives of this investigation was to find evidence that supports our interpretation of the C shaped root canal network. In fact, new advances in 3D mapping techniques help clarify the reliable etiology of the physiology of the Cshaped root canal network. Studies of extreme scenarios such as C-shaped root anatomy or morphology with rectangle and squared channels will also help us gain the wide range with root morphologies found in man’s teeth which eventually result in better care outcomes for patients and dentists and their satisfaction.
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Alencar, Juliana, André Luiz Borba do Nascimento, Paulo Duarte-Neto, and Maria Teresa Buril. "Disentangling Leaf Morphology in Daustinia montana (Convolvulaceae)." Systematic Botany 45, no. 4 (December 8, 2020): 921–30. http://dx.doi.org/10.1600/036364420x16033962925132.
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Abstract—Daustinia montana (Convolvulaceae) is the only species of the genus, and is notable for its wide leaf variability. To understand whether this plasticity is correlated with the distribution of the species, linear morphometric and leaf contour analyses were performed. Specimens from herbaria were photographed, and pre-established linear measurements were made. A multivariate analysis was then performed to test the strength of associations among morphological characteristics, climatic variables, and distribution of the species. Elliptic Fourier analysis based on 20 harmonics was used to generate shape descriptors, resulting in nine main components. With elliptic Fourier descriptors, a grouping tree was created that suggests the existence of six morphotypes in D. montana. Moreover, clustering analysis revealed two large groups distinguished mainly by leaf width. The present findings indicate that the morphotypes are strongly related to latitude and that other characteristics such as the type of indumentum are related to climatic variables.
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Churchill, Steven E., Kamryn Keys, and Ann H. Ross. "Midfacial Morphology and Neandertal–Modern Human Interbreeding." Biology 11, no. 8 (August 3, 2022): 1163. http://dx.doi.org/10.3390/biology11081163.
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Ancient DNA from, Neandertal and modern human fossils, and comparative morphological analyses of them, reveal a complex history of interbreeding between these lineages and the introgression of Neandertal genes into modern human genomes. Despite substantial increases in our knowledge of these events, the timing and geographic location of hybridization events remain unclear. Six measures of facial size and shape, from regional samples of Neandertals and early modern humans, were used in a multivariate exploratory analysis to try to identify regions in which early modern human facial morphology was more similar to that of Neandertals, which might thus represent regions of greater introgression of Neandertal genes. The results of canonical variates analysis and hierarchical cluster analysis suggest important affinities in facial morphology between both Middle and Upper Paleolithic early modern humans of the Near East with Neandertals, highlighting the importance of this region for interbreeding between the two lineages.
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Yurtseva, O. V., G. A. Lazkov, U. A. Ukrainskaja, and A. G. Deviatov. "Caelestium (Polygonaceae, Polygoneae), evidence bаsed on morphology." Novitates Systematicae Plantarum Vascularium, no. 50 (2019): 80–100. http://dx.doi.org/10.31111/novitates/2019.50.80.
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Morphological characters and fruit anatomy were analysed for distinguishing the new genus Caelestium, containing C. lazkovii (= Bactria lazkovii), endemic of the Central Tien Shan (Kyrgyzstan), and C. tianschanicum (= Polygonum tianschanicum), endemic of the Eastern Tien Shan (Xinjiang, China), from the genus Bactria in its updated circumscription, now containing only B. ovczinnikovii, endemic of the Pamir (Tajikistan). The genus Caelestium was established based on the results of molecular analyses and the details of the secondary structure of pre-rRNA of the ITS1 and ITS2 loci, but its morphology is poorly known. The morphological characteristics of Bactria and Caelestium were compared, and the anatomy of fruit was examined for these taxa and some species of Persepolium and Atraphaxis. Caelestium lazkovii and C. tianschanicum share the morphology of their leaf blades, perianth, fruits and styles, but differ in the color of annual shoots, the size of the perianth and fruits. They resemble Bactria ovczinnikovii in their life form, morphology of shoots, ochreas, inflorescences, and sporoderm ornamentation, but differ from the latter in the shape of leaf blades, fruits, and styles, micromorphology of tepals, and exocarp structure. SEM and LM images illustrating morphological characters are provided. The geographic ranges of the taxa are presented on the distribution map. Morphological characteristics distinguishing Caelestium and Bactria from Atraphaxis, Persepolium, and Polygonum are discussed.
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Xi, Juntong, Xin Hu, and Ye Jin. "Shape Analysis and Parameterized Modeling of Hip Joint." Journal of Computing and Information Science in Engineering 3, no. 3 (September 1, 2003): 260–65. http://dx.doi.org/10.1115/1.1607353.
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This paper presented a new method of shape analysis of hip joint. The bony surfaces of 12 male hipbone specimens and 26 female hipbone specimens were scanned using a 3D laser scanner. After performing local and global morphology analyses on the acetabulum surface, a rotation ellipsoid CAD model was applied to fit the acetabulum surface, and then an optimization technique was used to find the geometric parameters of the model. This study compared the fitting error between the sphere and rotation ellipsoid. The result is that the fitting error of rotation ellipsoid is smaller than the sphere, and the rotation ellipsoid can describe the shape of the acetabulum better. This shape likely decreases the cases of hip joint subluxation compared to a ball and socket joint.
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Wrozyna, Claudia, Thomas A. Neubauer, Juliane Meyer, Maria Ines F. Ramos, and Werner E. Piller. "Significance of climate and hydrochemistry on shape variation – a case study on Neotropical cytheroidean Ostracoda." Biogeosciences 15, no. 17 (September 14, 2018): 5489–502. http://dx.doi.org/10.5194/bg-15-5489-2018.
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Abstract. How environmental change affects a species' phenotype is crucial not only for taxonomy and biodiversity assessments but also for its application as a palaeo-ecological and ecological indicator. Previous investigations addressing the impact of the climate and hydrochemical regime on ostracod valve morphology have yielded contrasting results. Frequently identified ecological factors influencing carapace shape are salinity, cation, sulfate concentrations, and alkalinity. Here, we present a thorough approach integrating data with the carapace outline and surface details of the ubiquitous Neotropical cytheroidean ostracod species Cytheridella ilosvayi, as well as several climatic and hydrochemical variables, in order to investigate a potential link between morphology and environmental conditions. A recent study previously demonstrated considerable biogeographical variation in valve morphology among Floridian, Mexican and Brazilian populations of this species. We hypothesize that the climatic differences between the regions it inhabits and associated differences in hydrochemical regimes have influenced valve morphology and eventually led to biogeographically distinctive groups. Generalized least-squares Procrustes analyses based on outline and structural features were applied to the left and right valves of adult females and males. The analyses identified relative carapace length and shape symmetry as most important morphological characteristics representing shape differences across all datasets. Two-block partial least-squares analyses and multiple regressions indicate strong relationships between morphological and environmental variables, specifically with temperature seasonality, annual precipitation and chloride and sulfate concentrations. We suggest that increased temperature seasonality slowed down growth rates during colder months, potentially triggering the development of shortened valves with well-developed brood pouches. Differences in chloride and sulfate concentrations, related to fluctuations in precipitation, are considered to affect valve development via controlling osmoregulation and carapace calcification. The factors identified by our analyses represent hitherto unknown drivers for ostracod ecophenotypy in other species and therefore suggest that environmental predictors for morphological variability are not consistent across non-marine ostracods.
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Anderson, Philip S. L. "Biomechanics, functional patterns, and disparity in Late Devonian arthrodires." Paleobiology 35, no. 3 (2009): 321–42. http://dx.doi.org/10.1666/0094-8373-35.3.321.
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Studies of ecological structure and diversity over time in extinct groups have always been challenged by the inability to observe the behavior of fossil taxa directly. The only available evidence for function, behavior, and interactions between taxa is the morphological characteristics of the preserved fossils. Recent studies on modern groups have shown that morphological analyses may give misleading results in terms of ecological pattern and diversity. An alternative approach is to focus on functionally relevant aspects of morphology through a paleobiomechanical paradigm. The purpose of this research is to examine variation in the lower jaw morphology in Late Devonian arthrodire placoderms and develop biomechanical metrics that can be used to quantify functional diversity among this fossil group. Nine functionally relevant morphological characters were collected for 94 isolated arthrodire inferognathals from the Gogo Formation in Western Australia and the Cleveland Shale in Ohio. These data were used to address aspects of functional morphology, biomechanical disparity, and ecological structure in arthrodire placoderms from the Late Devonian. Results were compared with results from previous morphometric work on the same set of jaws.Statistical tests show a significant difference in functional characters between the two faunas. The differences may be related to phylogenetic differences between faunas, as the two major clades of arthrodire taxa included in this study are almost completely segregated between faunas. Average pairwise disparity analyses of the mechanical characters indicate that there is no significant difference in overall functional diversity between the Cleveland Shale and Gogo Reef arthrodire faunas. This result is at odds with previous results that show overall morphological disparity to be much higher in the Cleveland Shale. Clustering patterns within a multivariate function-space show tightly constrained functional groups of taxa independent of phylogenetic or shape-based morphological similarity. These functional groups illustrate a level of ecological diversity in Late Devonian arthrodires that is comparable to that in certain modern faunas.Further statistical analysis of the morphological and functional disparity of these Late Devonian taxa shows a disjoint between the two measures. Model I regression analysis of and Spearman rank-correlation analysis of average pairwise morphological and functional disparity measures indicate no significant relationship between morphological and functional disparity among the jaws used in this study. Although function is obviously derived from morphology, these results show that morphological shape analysis is not necessarily a good proxy for eco-functional diversity.
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Lemos Rocha, Leonardo F., Katharina Peters, Jacob Biboy, Jamie S. Depelteau, Ariane Briegel, Waldemar Vollmer, and Melanie Blokesch. "The VarA-CsrA regulatory pathway influences cell shape in Vibrio cholerae." PLOS Genetics 18, no. 3 (March 28, 2022): e1010143. http://dx.doi.org/10.1371/journal.pgen.1010143.
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Despite extensive studies on the curve-shaped bacterium Vibrio cholerae, the causative agent of the diarrheal disease cholera, its virulence-associated regulatory two-component signal transduction system VarS/VarA is not well understood. This pathway, which mainly signals through the downstream protein CsrA, is highly conserved among gamma-proteobacteria, indicating there is likely a broader function of this system beyond virulence regulation. In this study, we investigated the VarA-CsrA signaling pathway and discovered a previously unrecognized link to the shape of the bacterium. We observed that varA-deficient V. cholerae cells showed an abnormal spherical morphology during late-stage growth. Through peptidoglycan (PG) composition analyses, we discovered that these mutant bacteria contained an increased content of disaccharide dipeptides and reduced peptide crosslinks, consistent with the atypical cellular shape. The spherical shape correlated with the CsrA-dependent overproduction of aspartate ammonia lyase (AspA) in varA mutant cells, which likely depleted the cellular aspartate pool; therefore, the synthesis of the PG precursor amino acid meso-diaminopimelic acid was impaired. Importantly, this phenotype, and the overall cell rounding, could be prevented by means of cell wall recycling. Collectively, our data provide new insights into how V. cholerae use the VarA-CsrA signaling system to adjust its morphology upon unidentified external cues in its environment.
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Burr, Tom, Ian Schwerdt, Kari Sentz, Luther McDonald, and Marianne Wilkerson. "Overview of Algorithms for Using Particle Morphology in Pre-Detonation Nuclear Forensics." Algorithms 14, no. 12 (November 24, 2021): 340. http://dx.doi.org/10.3390/a14120340.
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A major goal in pre-detonation nuclear forensics is to infer the processing conditions and/or facility type that produced radiological material. This review paper focuses on analyses of particle size, shape, texture (“morphology”) signatures that could provide information on the provenance of interdicted materials. For example, uranium ore concentrates (UOC or yellowcake) include ammonium diuranate (ADU), ammonium uranyl carbonate (AUC), sodium diuranate (SDU), magnesium diuranate (MDU), and others, each prepared using different salts to precipitate U from solution. Once precipitated, UOCs are often dried and calcined to remove adsorbed water. The products can be allowed to react further, forming uranium oxides UO3, U3O8, or UO2 powders, whose surface morphology can be indicative of precipitation and/or calcination conditions used in their production. This review paper describes statistical issues and approaches in using quantitative analyses of measurements such as particle size and shape to infer production conditions. Statistical topics include multivariate t tests (Hotelling’s T2), design of experiments, and several machine learning (ML) options including decision trees, learning vector quantization neural networks, mixture discriminant analysis, and approximate Bayesian computation (ABC). ABC is emphasized as an attractive option to include the effects of model uncertainty in the selected and fitted forward model used for inferring processing conditions.
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Combes, S. A., and T. L. Daniel. "Shape, flapping and flexion: wing and fin design for forward flight." Journal of Experimental Biology 204, no. 12 (June 15, 2001): 2073–85. http://dx.doi.org/10.1242/jeb.204.12.2073.
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SUMMARY Both kinematics and morphology are critical determinants of performance in flapping flight. However, the functional consequences of changes in these traits are not yet well understood. Traditional aerodynamic studies of planform wing shape have suggested that high-aspect-ratio wings generate more force per area and perform more efficiently than low-aspect-ratio wings, but these analyses may neglect critical components of flapping flight such as unsteady fluid dynamics and wing or fin flexion. In this paper, we use an unsteady potential flow analysis that incorporates wing flexion to test predictions of optimal wing shape under varying degrees of unsteady motion and wing flexion. We focus on forward flapping flight and examine the effects of wing/fin morphology and movements on thrust generation and efficiency. We test the model by comparing our predictions with kinematic data derived from the aquatic flight of the ratfish Hydrolagus colliei. Our analyses show that aspect ratio and the proportion of area in the outer one-fifth of the wing can characterize wing shape in terms of aero- or hydrodynamic performance. By comparing the performance of wings that vary in these two parameters, we find that traditional predictions of optimal wing shape are valid only under limited circumstances (when flapping frequency is low, wings are stiff or wings are tapered at the tips). This indicates a complex relationship between locomotor traits and performance and helps explain the diversity of wing kinematics and morphologies observed in nature.
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Lima Boroni, Natália, Leonardo Souza Lobo, Pedro Seyferth R. Romano, and Gisele Lessa. "Taxonomic identification using geometric morphometric approach and limited data: an example using the upper molars of two sympatric species of Calomys (Cricetidae: Rodentia)." Zoologia 34 (August 22, 2017): 1–11. http://dx.doi.org/10.3897/zoologia.34.e19864.
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The taxonomic identification of micromammals might be complicated when the study material is fragmented, as it is the case with pellets and fossil material. On the other hand, tooth morphology generally provides accurate information for species identification. Teeth preserve notably well, retaining their original morphology, unlike skulls and mandibles, which can get crushed or have missing parts. Here, we explored a geometric morphometrics approach (GM) to identify fragmented specimens of two sympatric Calomys Waterhouse, 1837 species – Calomys tener (Winge, 1888) and Calomys expulsus (Lund, 1841) – using the morphology of intact molars as the basis for identification. Furthermore, we included some specimens of uncertain taxonomic identification to test their affinities and the utility of the shape of the molar to identify incomplete specimens. We evaluated the variations in the shape of the first upper molar (M1) among 46 owl pellets specimens of Calomys, including C. expulsus (n = 15), C. tener (n = 15), and unidentified specimens treated as Calomys sp. (n = 16) through GM analysis using 17 landmarks. The data was explored using PCA, PERMANOVA, and Discriminant analyses over the Procrustes residuals matrix were applied to evaluate inter- and intraspecific shape differences. Also, we evaluated whether allometric shape differences could impact the data, but found no evidence of a correlation between size and shape. Our results support that shape differences in the M1 are effective for discriminating between C. tener and C. expulsus. Moreover, the unidentified specimens do not represent a third shape but could be identified with confidence either as C. tener or C. expulsus. Our results show that even with fragmentary materials, GM is a feasible and useful tool for exploring inter-specific shape differences and assisting in taxonomic identification as a complement to traditional qualitative description of diagnostic features in poorly preserved specimens.
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Santos, E. G. N., M. Chame, V. A. Chagas-Moutinho, and C. P. Santos. "Morphology and molecular analysis ofOncicola venezuelensis(Acanthocephala: Oligacanthorhynchidae) from the ocelotLeopardus pardalisin Brazil." Journal of Helminthology 91, no. 5 (September 27, 2016): 605–12. http://dx.doi.org/10.1017/s0022149x16000651.
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AbstractOncicola venezuelensisMarteau, 1977 was found parasitizing adults ofLeopardus pardalis(Linnaeus) found dead in Serra da Capivara National Park, Piauí state, Brazil, a new geographical locality reported for the species. The diversity ofOncicolaTravassos, 1916 species is large, but genetic data are scarce. This article presents the results of genetic, morphological and ultrastructural studies carried out for taxonomic purposes. The first ultrastructural view showed a globular, short proboscis with 36 hooks, divided into six longitudinal rows of six hooks each. Hooks differ in size and shape: hooks I, II and III have a ‘chisel-shaped’ tip. The genetic profile included new sequences of ribosomal DNA ITS1, 5.8S and ITS2, and partial 28S rRNA regions. The results of maximum-likelihood tree analyses for each region showed Oligacanthorhynchidae Southwell et Macfie, 1925 close to Gigantorhynchidae Hamann, 1892 (supported >91%). Both use mammals and birds as definitive hosts. Morphological and ultrastructural studies combined with genetic analysis shed more light on the diversity ofOncicolaspecies.
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Teixeira, Marcelo Costa, Caroline Turchetto, Renan Maestri, and Loreta B. Freitas. "Morphological characterization of sympatric and allopatric populations of Petunia axillaris and P. exserta (Solanaceae)." Botanical Journal of the Linnean Society 192, no. 3 (January 15, 2020): 550–67. http://dx.doi.org/10.1093/botlinnean/boz064.
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Abstract Floral morphological traits are frequently used to identify species, including those that are closely related and show low genetic diversity, and floral shape and colour are known to play an important role in diversification and species isolation. Floral morphology in Petunia (Solanaceae) is considered a driver of diversification because of its association with pollinators. Here, flower morphology was characterized through morphometric analyses and floral pigments. Our main aim was to determine corolla shape in populations of Petunia axillaris and P. exserta and their natural hybrids and how floral display, size and colour are involved in pollinator attraction. In addition, we investigated floral pigments in P. exserta and different hybrid classes. The results from morphometric analyses revealed that each species has a specific floral shape, independent of the collection site. By contrast, in two contact zones, a mosaic of floral phenotypes was observed with some hybrid classes based on corolla colour being placed close to P. exserta. The results suggest that several generations of hybrids or backcrossing could have given rise to this floral diversity in contact zones.
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Echarri, Sebastian, Marcos D. Ercoli, M. Amelia Chemisquy, Guillermo Turazzini, and Francisco J. Prevosti. "Mandible morphology and diet of the South American extinct metatherian predators (Mammalia, Metatheria, Sparassodonta)." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 106, no. 4 (December 2015): 277–88. http://dx.doi.org/10.1017/s1755691016000190.
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ABSTRACTSparassodonta is a diverse group of extinct metatherian predators that include forms with diets ranging from omnivores to hypercarnivores, including potential bone-crushers and sabre-tooth specialised species. Most of the previous dietary studies on the group were based on qualitative approaches or dental morphometric indexes and/or bite force estimations. In this study, we explore the evolution of mandible shape and diet of Sparassodonta in a comparative phylogenetic framework, using geometric morphometric tools and allometric and discriminant analyses. We analysed the mandible shape of 142 extant species of marsupials and placental carnivores, and 15 fossil sparassodont species. We found that the relationship between shape and size of the mandible is strongly structured by phylogeny, where the more derived borhyaenoids tend to possess stronger and larger mandibles. Derived borhyaenoid sparassodonts and basal borhyaenoids were classified as hypercarnivores (with short and robust mandibular body). Hathliacynid were classified as mesocarnivores or as hypercarnivores, but with lower probabilities and less specialised morphologies (with a long and slender mandible). Although dental morphology suggests that most of the species of Sparassodonta would have been hypercarnivores, the robustness of the mandible seems to be informative regarding the prey size and degree of specialisation. The relationship between mandibular size and shape, and talonid/trigonid relative size, is strongly influenced by the phylogenetic legacy, suggesting that ecological factors could have influenced the evolution of the sparassodonts.
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Ordynets, Alexander, Sarah Keßler, and Ewald Langer. "Geometric morphometric analysis of spore shapes improves identification of fungi." PLOS ONE 16, no. 8 (August 5, 2021): e0250477. http://dx.doi.org/10.1371/journal.pone.0250477.
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Morphology of organisms is an essential source of evidence for taxonomic decisions and understanding of ecology and evolutionary history. The geometric structure (i.e., numeric description of shape) provides richer and mathematically different information about an organism’s morphology than linear measurements. A little is known on how these two sources of morphological information (shape vs. size) contribute to the identification of organisms when implied simultaneously. This study hypothesized that combining geometric information on the outline with linear measurements results in better species identification than either evidence alone can provide. As a test system for our research, we used the microscopic spores of fungi from the genus Subulicystidium (Agaricomycetes, Basidiomycota). We analyzed 2D spore shape data via elliptic Fourier and principal component analyses. Using flexible discriminant analysis, we achieved the highest species identification success rate for a combination of shape and size descriptors (64.7%). The shape descriptors alone predicted species slightly better than size descriptors (61.5% vs. 59.1%). We conclude that adding geometric information on the outline to linear measurements improves the identification of the organisms. Despite the high relevance of spore traits for the taxonomy of fungi, they were previously rarely analyzed with the tools of geometric morphometrics. Therefore, we supplement our study with an open access protocol for digitizing and summarizing fungal spores’ shape and size information. We propagate a broader use of geometric morphometric analysis for microscopic propagules of fungi and other organisms.
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Chaiphongpachara, Tanawat, and Sedthapong Laojun. "Annual Variability of Wing Morphology in Culex sitiens Wiedemann (Diptera, Culicidae) Mosquito Vectors from the Coastal Area of Samut Songkhram Province, Thailand." Journal of Parasitology Research 2019 (March 3, 2019): 1–7. http://dx.doi.org/10.1155/2019/3978965.
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Culex sitiens Wiedemann (Diptera, Culicidae) is a mosquito vector that is found in coastal areas. Effective control of mosquitoes requires knowledge of the biology, ecology, and behavior of the vector as well as of various other aspects, including its morphology. Currently, variations in the wing size and shape of coastal Cx. sitiens have not been described. Here, morphological changes were studied in the wings of Cx. sitiens from a coastal area of Samut Songkhram Province, Thailand. Samples were collected at night (6:00 pm–6:00 am) during single weeks of September in the years 2015–2017 using Center for Disease Control light traps with dry ice as bait. Eighteen landmarks of each individual were selected and digitized for landmark-based geometric morphometric analyses. Wing size variability was estimated using the isometric estimator of centroid size. Wing-shape variables were computed as Procrustes superimposition with residual coordinates of the 18 landmarks following a Generalized Procrustes Analysis and the principal components of residual coordinates. Degrees of wing-shape dissimilarity among individuals were analyzed using discriminant analysis or canonical variate analysis, which was illustrated in a discriminant space of canonical variables. Differences in wing size and shape among populations were calculated using nonparametric permutations based on 1000 runs with Bonferroni correction tests at a p-value of <0.05. The wing sizes and shapes of the mosquitoes differed significantly between observation years in all population groups, as indicated by nonparametric tests (1000 runs) with the Bonferroni correction. Differing rainfall between observation years was related to morphological changes in mosquito populations, presumably reflecting environmental adaptation. Differences in the wing morphology of Cx. sitiens between annual populations reflect adaptation to environmental variables such as rainfall and may affect the potential to act as insect vectors of human disease. These observations may facilitate the development of tools for managing mosquito-borne disease.
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Dale, Katherine E., M. Timothy Tinker, and Rita S. Mehta. "Larval morphology predicts geographical dispersal range of Eastern Pacific eels." Biological Journal of the Linnean Society 128, no. 1 (June 27, 2019): 107–21. http://dx.doi.org/10.1093/biolinnean/blz092.
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Abstract The geographical range of many marine species is strongly influenced by the dispersal potential of propagules such as eggs and larvae. Here, we investigate morphological diversity and the effect of body shape on geographical range of leptocephali, the unique, laterally compressed larvae of eels (order Anguilliformes). We used phylogenetically informed analyses to examine the morphological variation of larvae for 17 Eastern Pacific eel species from three adult habitats. We also investigated whether morphological traits of leptocephali could predict larval latitudinal range, hypothesizing that body shape may influence passive dispersal via currents. We found that no two species shared the same multivariate growth trajectories, with the size and scaling of pectoral fin length and snout-to-anus length being particularly variable. Larvae with longer relative predorsal and snout-to-anus lengths at median sizes exhibited wider larval geographical ranges. Body aspect ratio and maximum body length at metamorphosis, two traits we hypothesized to be important for passive transport, were not significant predictors of maximal larval range. We discovered an increase in phylogenetic signal over larval development as eels approach metamorphosis, potentially due to similar selective pressures between related species (such as juvenile habitat or adult morphology). Lastly, we conclude that larval body shape is probably influenced by adult habitat and adult morphology.
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Hoffmann, René, Manuel F. G. Weinkauf, and Dirk Fuchs. "Grasping the shape of belemnoid arm hooks—a quantitative approach." Paleobiology 43, no. 2 (February 8, 2017): 304–20. http://dx.doi.org/10.1017/pab.2016.44.
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AbstractChitinous arm hooks (onychites) of belemnoid coleoid cephalopods are widely distributed in Mesozoic sediments. Due to their relative abundance and variable morphology compared with the single, bullet-shaped, belemnite rostrum, arm hooks came into the focus of micropaleontologists as a promising index fossil group for the Jurassic–Cretaceous rock record and have been the target of functional, ecological, and phylogenetic interpretations in the past. Based on three well-preserved arm crowns of the Toarcian diplobelid Chondroteuthis wunnenbergi, we analyzed the shape of a total of 87 micro-hooks. The arm crown of Chondroteuthis is unique in having uniserial rather than biserial hooks. The first application of elliptic Fourier shape analysis to the arm weapons of belemnoid coleoids allows for the distinction of four micro-hook morphotypes and the quantification of shape variation within these morphotypes. Based on the best-preserved arm crown, we reconstructed the distribution of morphotypes within the arm crown and along a single arm. Our quantitative data support former observations that smaller hooks were found close to the mouth and at the most distal arm parts, while the largest hooks were found in the central part of the arm crown. Furthermore, we found a distinct arm differentiation, as not every arm was equipped with the same hook morphotype. Here, we report the functional specialization of the belemnoid arm crown for the first time and speculate about the potential function of the four morphotypes based on comparisons with modern cephalopods. Our analyses suggest a highly adapted functional morphology and intra-individual distribution of belemnoid hooks serving distinct purposes mainly during prey capture.
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Janssen, Anne F. J., Sophia Y. Breusegem, and Delphine Larrieu. "Current Methods and Pipelines for Image-Based Quantitation of Nuclear Shape and Nuclear Envelope Abnormalities." Cells 11, no. 3 (January 20, 2022): 347. http://dx.doi.org/10.3390/cells11030347.
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Any given cell type has an associated “normal” nuclear morphology, which is important to maintain proper cellular functioning and safeguard genomic integrity. Deviations from this can be indicative of diseases such as cancer or premature aging syndrome. To accurately assess nuclear abnormalities, it is important to use quantitative measures of nuclear morphology. Here, we give an overview of several nuclear abnormalities, including micronuclei, nuclear envelope invaginations, blebs and ruptures, and review the current methods used for image-based quantification of these abnormalities. We discuss several parameters that can be used to quantify nuclear shape and compare their outputs using example images. In addition, we present new pipelines for quantitative analysis of nuclear blebs and invaginations. Quantitative analyses of nuclear aberrations and shape will be important in a wide range of applications, from assessments of cancer cell anomalies to studies of nucleus deformability under mechanical or other types of stress.
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KARSTEDT, FERNANDA, MARINA CAPELARI, TIMOTHY J. BARONI, DAVID L. LARGENT, and SARAH E. BERGEMANN. "Phylogenetic and morphological analyses of species of the Entolomataceae (Agaricales, Basidiomycota) with cuboid basidiospores." Phytotaxa 391, no. 1 (January 29, 2019): 1. http://dx.doi.org/10.11646/phytotaxa.391.1.1.
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The generic or subgeneric delimitation by morphology of the Entolomataceae (Agaricales, Basidiomycota) is often based on the habit and external features of the basidiomata, the hyphal arrangement of the pileus surface and the shape of the basidiospores, which possess either bumps or undulate-pustules forming short ridges, or longitudinal ridges or are obviously angular with four to nine angles in profile view. Here, we examine the basidiospore shape of species in the /Entoloma clade described as cuboid to evaluate its importance in taxonomy using both phylogenetic and detailed analyses of the shape with Scanning Electron Microscopy. Our phylogenetic analyses support the placement of species with cuboid basidiospores into one of two clades. Based on this separation, two new subgenera of Entoloma are proposed: Cuboeccilia with an omphalinoid habit and fusoid cystidia and Cubospora which has a mycenoid to tricholomatoid habit and clavate, rarely fusoid cheilocystidia.
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DOĞAN, CAHİT, and EDİBE ÖZMEN BAYSAL. "Pollen morphology of the coastal species of Turkish Limonium (Plumbaginaceae)." Phytotaxa 388, no. 3 (January 18, 2019): 212. http://dx.doi.org/10.11646/phytotaxa.388.3.1.
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The pollen morphology of nine Limonium species (Plumbaginaceae), occurring along the coastal saline habitats of Turkey, are investigated. Pollen slides were prepared according to the methods of Wodehouse (W) and Erdtman (E) and examined using light microscope. Then pollen grains were placed directly to stubs and covered by gold-palladium mixture for scanning electron analyses. Pollen grains are usually tricolpate, rarely syncolpate, dicolpate, tetracolpate, and pentacolpate. Shape of pollen grains are varing from prolate-sphaeroidal to oblate. Medium to large sized pollen grains of Limonium has long and wide colpi with distinct margins, and acute terminals. Exine structure is semi-tectate and exine ornamentation is microreticulate-microechinate or reticulate-microechinate. Pollen grains of Limonium species have shown variation on colpus type, shape and exine ornamentation. Examined Limonium species can be seperated in three unformal groups according to the palynological features, and their pollen definitions have been done. Besides, a taxonomic key was proposed for quick and accurate identification based on different palyno-morphological characters.
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Khang, Tsung Fei, Oi Yoon Michelle Soo, Wooi Boon Tan, and Lee Hong Susan Lim. "Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution." PeerJ 4 (February 4, 2016): e1668. http://dx.doi.org/10.7717/peerj.1668.
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Background.Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions.Materials and Methods.We used data from anchor morphometry, body size and morphology of 13Ligophorus(Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts:Moolgarda buchanani(Bleeker) andLiza subviridis(Valenciennes) from Malaysia. Anchor shape and size data (n= 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams’sKmultwas used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data.Results.We discriminated 12 of the 13Ligophorusspecies using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root point, and the length between the inner root point and the dent point. The species onM. buchananievolved larger, more robust anchors; those onL. subviridisevolved smaller, more delicate anchors. Anchor shape and size were significantly correlated, suggesting constraints in anchor evolution. Tight integration between the root and the point compartments within anchors confirms the anchor as a single, fully integrated module. The correlation between male copulatory organ morphology and size with anchor shape was consistent with predictions from the Rohde-Hobbs hypothesis.Conclusions.Monogenean anchors are tightly integrated structures, and their shape variation correlates strongly with phylogeny, thus underscoring their value for systematic and evolutionary biology studies. Our MonogeneaGM R package provides tools for researchers to mine biological insights from geometric morphometric data of speciose monogenean genera.
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Hussain, Raabid, Attila Frater, Roger Calixto, Chadlia Karoui, Jan Margeta, Zihao Wang, Michel Hoen, et al. "Anatomical Variations of the Human Cochlea Using an Image Analysis Tool." Journal of Clinical Medicine 12, no. 2 (January 8, 2023): 509. http://dx.doi.org/10.3390/jcm12020509.
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Understanding cochlear anatomy is crucial for developing less traumatic electrode arrays and insertion guidance for cochlear implantation. The human cochlea shows considerable variability in size and morphology. This study analyses 1000+ clinical temporal bone CT images using a web-based image analysis tool. Cochlear size and shape parameters were obtained to determine population statistics and perform regression and correlation analysis. The analysis revealed that cochlear morphology follows Gaussian distribution, while cochlear dimensions A and B are not well-correlated to each other. Additionally, dimension B is more correlated to duct lengths, the wrapping factor and volume than dimension A. The scala tympani size varies considerably among the population, with the size generally decreasing along insertion depth with dimensional jumps through the trajectory. The mean scala tympani radius was 0.32 mm near the 720° insertion angle. Inter-individual variability was four times that of intra-individual variation. On average, the dimensions of both ears are similar. However, statistically significant differences in clinical dimensions were observed between ears of the same patient, suggesting that size and shape are not the same. Harnessing deep learning-based, automated image analysis tools, our results yielded important insights into cochlear morphology and implant development, helping to reduce insertion trauma and preserving residual hearing.
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Syutkina, Taisiya, Mario Juan Gordillo Pérez, Silvia Teresita Hernández Godoy, Carlos Arredondo Antúnez, and Armando Rangel Rivero. "Intragroup variation in the Pre-Columbian Cuba population: A perspective from cranial morphology." Anthropological Review 84, no. 3 (September 30, 2021): 233–55. http://dx.doi.org/10.2478/anre-2021-0021.
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The paper aims to study intragroup variation inside the two pre-Columbian Cuban populations: the aceramic Archaic and the ceramic Taino groups, based on their cranial morphology. The latter applied artificial cranial deformation to all its members, so the groups are referred to as “non-deformed” and “deformed” samples here. Studies across different disciplines suggest evidence of cultural and biological diversity inside the non-deformed group, while local variations of applying the deforming device can be responsible for shape variation across the deformed group. Cranial metrics and non-metric cranial traits of the 92 crania of Cuban origin were analyzed, although the sample size varied between the analyses due to the incompleteness of the crania. Geometric morphometrics was applied to the deformed crania to study the shape variation across the sample. Three deformed crania from the Dominican Republic were analyzed together with the deformed Cuban sample to test the variability of the practice between the islands. Principal component analysis and the Mantel test did not reveal any geographic differences in the cranial metric traits. No morphological differences associated with the antiquity of materials could be seen either based on the available data. The principal component analysis of the Procrustes coordinates of the cranial vault outline in the lateral norm revealed continuous variability of cranial shapes from the ones with more flattened frontal and occipital bones to the more curved outlines, which is probably explained by individual variation. Non-metric traits variation revealed bilateral asymmetry in the expression of the occipito-mastoidal ossicles among the deformed crania. In conclusion, the study did not support assumptions about morphological diversity inside the studied samples or proved the impossibility of available craniological data to reflect possible intragroup differentiation at the moment.
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Alencar, C. E. R. D., P. A. Lima-Filho, W. F. Molina, and F. A. M. Freire. "Sexual Shape Dimorphism of the Mangrove CrabUcides cordatus(Linnaeus, 1763) (Decapoda, Ucididae) Accessed through Geometric Morphometric." Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/206168.
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Sexual dimorphism is often observed in Crustaceans. Considering the great diversity of this subphylum, only few reports are found in the literature and most are mainly based on traditional morphometry. The present study uses geometric morphometrics analysis to identify sexual dimorphism by shape variation in the overexploited semiterrestrial crabUcides cordatus, species with great social and economic importance in South America. Comparative morphology analyses were performed by using the outer face of the propodus of major cheliped, dorsal and anterior region of carapace shape. Significant differences in shape between sexes were detected in these body areas. The causes of dimorphism presented in this species are not clear but, analogous to other possibly associated species, it may be inferred that the causes are with adaptations to body ability of reproductive potential (females), and of reproductive behaviour and agonistics encounters (males). Additional analyses on courtship displays and other reproductive aspects should provide better comprehension of functionality of this morphological differentiation.
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Lin, Ai Qin, Min Li Zheng, Chun Guang Fan, and Lin Yang. "Surface Morphology Simulation of High Speed Milled of Face Milling Cutters." Advanced Materials Research 305 (July 2011): 225–29. http://dx.doi.org/10.4028/www.scientific.net/amr.305.225.
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To surface milling cutters for research object, established considering the single spindle partial pendulum milling cutter tooth surfaces of high speed cutting 3d surface morphology simulation model by using graphic matrix transformation principle and vector algorithms. Comparing the simulation and forecast of surface morphology and surface roughness with the actual machining surface morphology and surface roughness by using the workpiece simulation algorithm meshing, we verify the correctness of the simulation model. The simulation analyses the influence regularity of surface morphology and surface roughness by changing cutting parameters and geometrical parameters. This can help us choosing the reasonable cutting parameters and geometrical parameters and have significance on the actual machining. The surface milling cutters are high efficiency and good quality of cutting big plane or curved surface. With the development of high speed cutting technology, in high speed milling process, product crumbs tumor and scales thorn hardly exists, so cutter geometrical parameters, cutting data and so on will be the main influence reasons of surface roughness. In order to satisfied the quality requirements, at present, we choice tools and determine the milling parameters depending on experience but it is limited. The surface roughness of the processing components is reflected intuitively by processed surface of microscopic geometric shape. So surface of microscopic geometric shape produced by theory emulation is significant to forecast the surface roughness and selecting reasonable cutting parameters. Currently, there are some simulation method researches about surface of microscopic geometric shape. Zhao Xiao ming et al [1, 2] has researched the simulation modeling of microscopic geometric shape of ball end mills during processing; Xu An ping et al [3, 4] has researched the simulation modeling methods of peripherally milling processing; Zhang Guang Peng et al [5] has researched the inversion multiple tooth surfaces of the milling cutter surface morphology simulation and develop simulation software. But all above researches are ideal simulation of surface shape. There are few researches about simulation of surface shape on condition of spindle partial pendulum. Based on object of surface milling cutters, this article researches simulation modeling methods of surface topography on condition of high speed milling and give an account of the corresponding simulation algorithm. From the article, we also get the influence law of microscopic geometric shape depending on different milling dosage, cutter geometrical parameters and eccentric quantity and get the significance conclusion to actual production.
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Wani, Ryoji, and Royal H. Mapes. "Conservative evolution in nautiloid shell morphology: Evidence from the Pennsylvanian nautiloid Metacoceras mcchesneyi from Ohio, USA." Journal of Paleontology 84, no. 3 (May 2010): 477–92. http://dx.doi.org/10.1666/09-158.1.
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Morphometric analyses of shell morphology in the Pennsylvanian nautiloid Metacoceras mcchesneyi Murphy, 1970 (Cephalopoda, Mollusca) recovered from coal mines in Madison Township, Columbiana County, Ohio, USA, reveal the ontogenetic change from hatching to maturity as well as intra-specific variation of shell morphology. The shell shape of M. mcchesneyi has isometric relationships, and the umbilicus diameter between umbilical shoulders has a positive allometric relationship with shell diameter. These show that the relative whorl shape was constant through the ontogeny, but the umbilicus became relatively broader with growth. The siphuncle position moved from a ventro-central position toward the center with growth until 420° of the total rotational angle had been attained. A constriction was recognized on the early whorl at 9.5 mm in shell diameter, and the interval angles of succeeding septa were changed at the 5th septum, indicating that hatching occurred at this diameter. The ventral apertural wall, the disappearance of ornamentation toward the last preserved aperture, and the last whorl separating from the previous whorl indicate that M. mcchesneyi attained maturity at ca. 70 mm in shell diameter. Most characteristics of shell morphology in M. mcchesneyi (the relative shell shape and ornamentation through ontogeny) are comparable to those in modern and younger fossil nautilids, irrespective of taxonomy and age, supporting the conclusion that evolutionary rates of shell morphology are conservative in nautilid history.