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893 result(s) for "Geometric morphometric analysis"
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Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae
A new troodontid dinosaur, Hypnovenator matsubaraetoheorum gen. et sp. nov., is described based on an articulated postcranial skeleton recovered from the fluvial deposits of the Albian Ohyamashimo Formation of the Sasayama Group in Tambasasayama City, Hyogo Prefecture, Japan. Hypnovenator is distinguished from other troodontids by four autapomorphies and a combination of additional features. Our phylogenetic analysis positions Hypnovenator as the oldest and one of the most basal troodontines, forming a clade with Gobivenator mongoliensis . The discovery of Hypnovenator suggests that small-bodied maniraptorans with a sleeping posture were common not only in environments with volcanic and eolian events or alluvial systems but also in fluvial systems. Geometric morphometric analysis of manual ungual phalanges shows that manual ungual phalanges I and III of Hypnovenator exhibit considerable morphological variation but are functionally similar, which differs from those of non-troodontine troodontids, reflecting the transition of manual motion within Troodontinae. Hypnovenator also has mosaic features in the pes related to cursoriality. This study reveals that asymmetrical arctometatarsus occurred by the Albian, and some morphological changes, such as shorter digit IV than digit III and non-ungual phalanges of digits III with roller joints and digit IV with weakly ginglymoid articulation, arose during the early Late Cretaceous.
Variability, asymmetry and sexual dimorphism in craniofacial anomalies in Loeys-Dietz syndrome 2: geometric morphometric analysis in mice
Loeys-Dietz syndrome is a rare connective tissue disorder characterized by life-threatening aortic aneurysm and distinctive craniofacial anomalies. It is caused by mutations along the transforming growth factor beta (TGF-β) signaling pathway (LDS1-6). We previously showed that craniofacial anomalies varied among LDS subtypes and that LDS2, caused by mutations in the TGFBR2 gene, exhibited the most severe and variable phenotype. In this study, we performed a thorough qualitative and quantitative analysis of craniofacial anomalies in a mouse model for LDS2, through micro computed tomography and 3D geometric morphometric analysis at multiple postnatal stages. We show that craniofacial shape in Tgfbr2 G357W/ + mice strongly deviates from their WT littermates from an early age and exhibit high variability and evidence of left–right asymmetry despite the pure genetic background. Cranial doming, shortening of the anterior part of the skull, widening of the space between orbits, reduction of mandibular size, suture fusion in the cranial vault and palate, and abnormal condylar shape were among features that were consistent with the phenotype seen in patients with LDS. Interestingly, several of these features were more prevalent and severe in females than in males, indicating potential sexual dimorphism, further supported by the trend observed in our revisited clinical data.
Anopheles neivai (Diptera: Culicidae) Morphogenetic Analysis from the Pacific Coast to the Premontane Humid Forest of Colombia
In specific altitude ranges, biotic and abiotic factors can impact vector mosquitoes’ adaptation capacity, affecting their population differentiation. This study analyses if there exist morphological and genetic differences in four Anopheles (Kerteszia) populations in specific altitude ranges from the Colombian pacific coast to the premontane humid forests in Valle del Cauca, Colombia. Likewise, it is compared if the vector mosquito groups analyzed were genetically similar to the ones available in the region. Traditional and geometric morphometric analysis and the molecular marker CO-I were used. The research found that vector mosquitoes’ littoral populations differentiated morphologically according to their cross veins wing shapes compared to the other three groups in higher altitudes. Their genetic distances fluctuate between 4.95% and 6.84%, indicating that vector mosquitoes’ littoral populations belong to Anopheles neivai s.s. while the ones of higher altitudes are related to An. neivai 8—a lineage previously proposed based solely on molecular data. The study concludes that vector mosquitoes at the pacific Colombian coast from the littoral area in lower altitudes maintain a vast genetic variability with uniform populations; however, in higher altitudes, vector mosquitoes acquire molecular and morphological differences that may include the settlement of other lineages.
Development of olive cultivation at the site of Sikyon, Greece: evidence from the charred olive remains from the late Classical/early Hellenistic to the Roman period
Olea europaea (olive) is a typical fruit tree of the Mediterranean basin where it has been widely cultivated for millennia. In the Aegean, the growing of olives is known since the Neolithic period, and it has been suggested that their cultivation increased during the 1st millennium bce . The olive and its by-products have played dynamic roles in the economies of the regions in which it was grown. The finding of charred olive stones at the site of Sikyon in the northeastern Peloponnese, Greece, reflects the role of olives in this region during the second half of the 1st millennium bce until the beginning of the 1st millennium ce . The results of geometric morphometric analysis of some complete olive stones found in various archaeological contexts at Sikyon provide information on the state of olive cultivation and the richness of the various olive varieties grown there.
Pilbara Fat-Tailed Macropods: Using Multivariate and Morphometric Analyses to Explore Spatial and Stylistic Variability
This paper presents a pioneering analysis of a distinctive engraved motif from the Pilbara region: the fat-tailed macropod (kangaroo). This stylistic analysis has used a combination of conventional qualitative and multivariate techniques with less commonly deployed geometric morphometrics analysis (GMA). Focusing on a distinctive engraved motif in Australia’s northwest, this study has quantified the stylistic characteristics of the fat-tailed macropod depictions by identifying the significant attributes that contribute to this motif’s schema. By using both multivariate analysis and GMA software, we have developed a more nuanced understanding of the synchronic and diachronic dimensions of this deep-time indigenous artistic tradition. Differing levels of stylistic homogeneity across this region are interpreted as distinctive signalling intentionality by the artists. Based on the precepts of information exchange theory, stylistic homogeneity is interpreted as indicating an open social system, while stylistic heterogeneity represents people signalling social difference(s). The geographic distribution of this distinctive motif, and its specific placement within sites demonstrates different inscribing behaviours across the Pilbara. This is interpreted as evidence for intentional identity production by Pilbara artists. GMA identifies that a major contributing factor to the variability in this motif form is in the distinctive depictions of posture and gait. Indigenous knowledge of kangaroo behaviours is demonstrated in these iconic Pilbara motifs.
Geometric Morphometric Analysis of Hard and Soft Tissue in Class III Malocclusion Before and Near-End Orthodontic Treatment
Background/Objectives: Geometric morphometric analysis (GMA) is a statistical method that captures and quantifies shape variation. This study aimed to assess hard and soft tissue shape variations and changes following orthodontic treatment in Class III skeletal malocclusion using GMA. Methods: A retrospective study was conducted on 84 lateral cephalometric radiographs (pre-treatment and near-end treatment) of Class III patients aged 16–40 years (ANB < 2°). Thirty-five landmarks were digitized in Cartesian coordinates using MorphoJ software for shape analysis. Results: The sample included 62% females and 38% males, with a mean age of 24.7 ± 5.2 years. Vertical dimension variations (hypodivergent to hyperdivergent) contributed most to shape changes PC1 (23.35%), followed by anteroposterior variations PC2 (13.51%). Gender significantly influenced hard and soft tissue variation with 30.91%SS (F = 56.99, p < 0.0001). Males had significantly larger and longer ramus, body of the mandible, alveolar height, LAFH, TAFH and upper lip length. (PD: 0.026, p < 0.05). Significant shape changes were seen in the mandible (PD = 0.018, p < 0.05). SNB increased by 0.41° (from 81.73° ± 3.67°), and ANB improved by 0.46° but remained Class III (−0.33° ± 1.82°). Lower anterior facial height increased by 1.78 mm (p < 0.05). The lower incisors retroclined significantly (from 92° ± 8.56° to 87° ± 6.96°, p < 0.05), while the interincisal angle increased by 5.9°. Upper incisors remained procline (118° ± 11°, p > 0.05). Upper lip length increased by 0.4 mm (p < 0.05). Conclusions: Vertical and anteroposterior shape variations are notable within Class III malocclusion. Post-treatment changes in both hard and soft tissues indicate that orthodontic camouflage can enhance facial esthetics and skeletal balance. GMA provides objective quantification and visualization of these treatment-related craniofacial changes.
Geometric morphometric analysis of the brainstem and cerebellum in Chiari I malformation
Chiari I malformation (CMI) is characterized by inferior descent of the cerebellar tonsils through the foramen magnum and is associated with headache and neck pain. Many morphometric research efforts have aimed to describe CMI anatomy in the midsagittal plane using classical measurement techniques such as linear dimensions and angles. These methods are less frequently applied to parasagittal features and may fall short in quantifying more intricate anatomy with fewer distinct homologous landmarks. Landmark-based geometric morphometric techniques were used to asses CMI morphology in five anatomical planes of interest. Significant shape differences between CMI and age/sex-matched controls were found in the midsagittal (Pseudo-  = 5.4841,  = 0.001) and axial planes through the rostral medulla (Pseudo-  = 7.6319,  = 0.001). In addition to tonsillar descent, CMI principal component 1 (PC1) scores in the midsagittal protocol were associated with marked anterior concavity of the brainstem and generalized verticality of the cerebellum with anterior rotation of its anterior lobe. In the axial medulla/cerebellum protocol, CMI PC1 scores were associated with greater anterior-posterior (A-P) dimension with loss of medial-lateral (M-L) dimension. These results suggest that CMI is associated with greater curvature of the brainstem and spinal cord, which may perturb normal neural activities and disrupt cerebrospinal fluid movements. Previous reports on the A-P diameter of the posterior fossa in CMI have conflicted; our findings of greater A-P cerebellar dimensionality with concomitant loss of width alludes to the possibility that more caudal aspects of the posterior cranial fossa are more bowl-like (homogenous in axial dimensions) and less trough-like or elongated in the M-L direction.
Shape matters: relevance of carapace for brachyuran crab invaders
The increasing trend of biological invasions is one of the most concerning threats for ecosystems functioning. The identification of optimal characters determining the invasive potential of non-native species has always been a challenge in conservation studies. Morphological features can be used as a good proxy to address the invasive success in fish species, assuming that anatomical differences in comparison to native species can provide to newcomers ecological opportunities increasing their probability to become successful. Considering this, the present study constitutes the first applicative attempt of a model based on geometric morphometrics to demonstrate the importance of the carapace shape in the invasive ability in marine decapod crustaceans. The study was performed on the native brachyuran community of Alfacs Bay, in the Ebro Delta, the largest estuarine zone along the north-western Mediterranean, in which two recently established non-native crab species coexist: Dyspanopeus sayi and Callinectes sapidus. Results suggested that invaders with extreme carapace traits located peripherally in the community morphospace, such as C. sapidus, usually possess ecological advantages contributing to understand their success. Conversely, intermediate morphologies within the morphospace, such as D. sayi, imply ecological overlapping with native species reducing their community relevance. Besides, we also assessed the effect on the community morphospace of a hypothetical future invasive event from another crab species (Portunus segnis) with high probabilities to also colonize the community. Our outcomes confirm that the morphometric approach could be an alternative tool for assessing the potential ability of invasive crab species. However, further studies at different spatial and temporal scales, including additional traits and quantitative data from invasions, would be necessary to confirm the efficacy and usefulness of the methodology.
Shape variation in the carapace of Chinese mitten crabs (Eriocheir sinensis H. Milne Edwards, 1853) in Yangcheng Lake during the year-long culture period
To evaluate whether ontogenetic development over the grow-out culture period can cause geographical plasticity of carapace shape in a certain region, geometric morphometric analysis was used, in this study, to determine the ontogenetic changes in the carapace morphology of Chinese mitten crabs (Eriocheir sinensis) originating from Yangcheng Lake, China, during a year of growth from coin-sized juveniles to market-sized adults. The morphological differences in the carapace throughout the year of culture were characterized using a 35-landmark point system. We used principal component analysis and linear discriminant analysis to determine morphological variation using thin-plate spline analysis and mesh deformation. During the growth process, the changes in the carapace were mainly concentrated in the third and fourth anterolateral teeth and on the M-shaped pattern. During the growth of male and female crabs throughout the year, the shape of the carapace changed considerably over the first six months. Afterwards, the shape of the carapace began to stabilize and could not be differentiated through discriminant analysis. This study is the first to use geometric morphometrics to analyze the ontogenetic changes in the carapace shape of E. sinensis crabs native to Yangcheng Lake. The results demonstrate that it takes a long time for the carapace morphology of native crabs to stabilize.