Canonical Variate Analysis Research Articles

Morphological Variation of the Sea Silverside Odontesthes regia in Regions with Dissimilar Upwelling Intensity along the Humboldt Current System

We evaluated the influence of areas with dissimilar upwelling intensity along the Humboldt Current System on the morphological variation of the economically important sea silverside Odontesthes regia by using geometric morphometric (GM) and meristic data of populations sampled off Northern Peru, Central Peru, Southern Peru-Northern Chile, and Central-Southern Chile (CSCH). Multivariate analyses of variance, a UPGMA tree, and discriminant analyses of meristic counts separated CSCH individuals, which had slightly higher numbers of gill rakers and radius of the anal fin. Permutation tests and canonical variate analyses of GM data distinguished all populations and highlighted deformations in the head and fins. Variations in GM and meristic analyses were significantly correlated with values of the sea surface temperature and surface chlorophyll-a concentrations. Morphological differences among populations might be associated with the spatial coastal upwelling dynamic of the Humboldt Current System, which highlights the role that this system plays in relation to the phenotypic variation of fish.

Integrando análisis morfométricos y filogenéticos: de la sistemática fenética a la morfometría filogenética

Antecedentes y Objetivos: Se han acumulado métodos cuantitativos para el uso de mediciones lineales y coordenadas Cartesianas de puntos en análisis de la variación morfométrica. A diferencia de revisiones previas, aquí se enfatizan las bases teóricas de los espacios matemáticos y del morfoespacio de un carácter taxonómico. El objetivo de esta revisión es suministrar elementos conceptuales para una comprensión básica de los métodos morfométricos y estadísticos útiles en la sistemática bajo un enfoque filogenético. Métodos: Los datos morfométricos se están aplicando en estudios de biología comparativa, usando las filogenias como referencia. En contraste, las aplicaciones de la morfometría en sistemática han sido con el objetivo de agrupar y distinguir grupos taxonómicos fenéticamente con la similitud total. Bajo un enfoque filogenético, los datos morfométricos también se pueden usar para el estudio de la variación de caracteres taxonómicos, la identidad de los estados y la inferencia de filogenias. Los grupos taxonómicos debieran ser propuestos a partir de grupos monofiléticos descubiertos con métodos filogenéticos. Resultados clave: Se presentan las bases de la teoría de la morfometría, geometría vectorial, el espacio de Kendall, la distancia Procrustes, proyección de espacios tangenciales y construcción de hipercubos del morfoespacio. Se revisan conceptos estadísticos útiles para la aplicación de los Análisis de Componentes Principales y los Análisis de Variables Canónicas en sistemática. Particularmente se dan recomendaciones y ejemplos sobre el uso de mediciones lineales y coordenadas de puntos en análisis morfométricos para la identificación de especies, la variación de caracteres taxonómicos y en la inferencia de filogenias y clasificación. Conclusiones: El amplio acervo actual de métodos brinda la oportunidad de integrar los datos morfométricos para descubrir homología táxica y homología transformacional. Esto implica un cambio epistemológico necesario para transitar de aplicaciones bajo una sistemática fenética, a la integración de los análisis morfométricos como parte de la investigación filogenética.

Assessing zygomatic shape and size for estimating sex and ancestry in a South African sample

Unidentified, decomposed and skeletonised human remains are frequently found in South Africa, therefore, standardised, reliable and relevant sex and ancestry estimation methods are required for forensic identification. This study assessed sex and ancestral variation in zygomatic size and shape in a South African population using geometric morphometric analyses. The zygoma of 158 South African individuals were sampled. Eight zygomatic landmarks were captured in 3-dimensions using a Microscribe G2 digitiser and assessed using procrustean geometric morphometrics. Shape and size differences were analysed using multivariate linear regression, discriminant function and canonical variate analyses. Males had significantly larger zygomas than females. Significant shape variation was found between ancestral groups. Bantu-speaking and Mixed ancestry individuals had narrower, shorter and more anteriorly projecting orbital margins, whilst Europeans had vertically elongated and receded orbital margins. European ancestral groups were most discernible from Bantu-speakers and Mixed ancestral groups. Ancestry estimation accuracies improved when ancestry was aggregated with sex. Pairwise ancestry-linked comparisons in females were as follows; Bantu-speakers (76%) from Europeans (72%), Bantu-speakers (71%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (63%). Similarly, ancestry-linked comparisons in males were as follows; Bantu-speakers (77%) from Europeans (81%), Bantu-speakers (53%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (82%). Size differences are putatively linked to variations in hormone-regulated growth and muscular robusticity between males and females. Shape variations between ancestral groups are likely attributable to the heterogenous genetic and ancestral origins of the South African population. It is challenging to distinguish between South Africa Bantu speakers and Mixed ancestry people due to Mixed ancestry individuals having variable genetic contributions from Khoesan, Bantu-speakers, Europeans and Asians. Bantu-speaking and Mixed ancestry people had zygomatic morphologies consistent with historical thermoregulatory adaptations to sub-Saharan climates, reported in African-descendants. Zygomatic morphology in European descendants suggests ancestral origins from colder climatic regions. This study demonstrated the utility of the zygoma in distinguishing between ancestral groups in South Africa, but further research is required to develop population-specific standards to distinguish between South African populations with shared African ancestry. The zygoma shows a promising ability to estimate sex and ancestry in South Africans, suggesting population specific standards for this bone may be of forensic interest.

Morphometric and genetic characterizations of blue swimming crab Portunus segnis, (Forskal, 1775) along the Iranian coasts of the Persian Gulf and Oman Sea

Portunid crabs form the basis of important fisheries in many parts of the world, however, their population biology is poorly understood. The more than 90 species of the Portunidae are widely distributed in global oceans often with indistinct boundaries among species, especially in the Indian Ocean. To clarify the species occurrence and population genetic structure of Portunus pelagicus and Portunus segnis in Iranian waters, crab specimens were collected from four sites along the Iranian coast of the Persian Gulf and Oman Sea. For a subset of 40 sampled crabs, the Cytochrome C Oxidase subunit 1 (COI) was sequenced and compared among the four sites. This analysis identified P. segnis as the predominant species (39 out of 40 sequenced samples) with the infrequent occurrence of P. pelagicus (one out of 40 sampled). Genetic diversity analysis for P. segnis samples identified high to moderate haplotype (0.98) and nucleotide (0.04) diversities. Analysis of molecular variance (AMOVA) (ΦST=0.09629 P = 0.00673) revealed significant genetic differentiation between two sampling sites inside the Persian Gulf, at Chabahar and Qeshm which are 500 km apart. Comparisons of the variation in the carapace morphometrics of 104 male P. segnis among sites using canonical variate analysis showed significant differences among the four sampling sites (P < 0.0001). Overall, the results revealed a high degree of morphological and genetic heterogeneity in P. segnis over relatively small spatial scales in this region of the Indian Ocean. The morphological variability of this species is such that it masked the sympatric presence of the species, P. pelagicus. It is likely that other cryptic portunid congeners will be identified in other Indo-Pacific regions given the high level of genetic variability that has been previously described for P. pelagicus from this region.

Geometric morphometrics in the sulcus acusticus of the sagittae otolith as tool to discriminate species of the genus Centropomus (Centropomidae: Perciformes) from the southeastern Gulf of California

Due to the limited morphological differentiation among species of the genus Centropomus and the increased overlap of their meristic characters, in this study, we examined 114 sagittae otoliths by geometric morphometrics. Otoliths belonged to four species: Centropomus robalito (Jordan and Gilbert, 1881) Centropomus medius (Gunter, 1864), Centropomus nigrescens (Gunter, 1864), and Centropomus viridis (Lockington, 1877) collected by artisanal fishing carried out in the “Marismas Nacionales Nayarit” Biosphere Reserve and the continental shelf of the state of Nayarit. According to the canonical variate analysis, all four species were discriminated (100% correct) evidencing the high taxonomic value of sagittae otolith for these taxa. In our study, the morphology of sagittae otolith of four species of the genus Centropomus is documented for the first time.

Comparison of Wing, Ovipositor, and Cornus Morphologies between Sirex noctilio and Sirex nitobei Using Geometric Morphometrics.

Sirex noctilio F. (Hymenoptera: Siricidae) is an invasive woodwasp from Europe and North Africa. Globalization has led to an expanding global presence in pine forests. S. noctilio has been previously introduced outside of its native range and now co-occurs in trees with native S. nitobei Matsumura (first discovered in 2016). Damage to Pinus sylvestris var. mongolica Litv in northeast China can be attributed to two types of woodwasp. To distinguish the two species by the traditional taxonomic morphology, we mainly differentiate the color of the male’s abdomen and the female’s leg. There remains intraspecific variation like leg color in the delimitation of related genera or sibling species of Sirex woodwasps. In this study, we used landmark-based geometric morphometrics including principal component analysis, canonical variate analysis, thin-plate splines, and cluster analysis to analyze and compare the wings, ovipositors, and cornus of two woodwasps to ascertain whether this approach is reliable for taxonomic studies of this group. The results showed significant differences in forewing venation and the shapes of pits in the middle of ovipositors among the two species, whereas little difference in hindwings and cornus was observed. This study assists in clarifying the taxonomic uncertainties of Siricidae and lays a foundation for further studies of the interspecific relationships of the genus Sirex.

Geographic Skull Variation of the Japanese Weasel, Mustela itatsi in Islands Adjacent to Southern Kyushu

Skull morphology of Mustela itatsi from two islands adjacent to Kyushu, Kamikoshikijima and Yakushima Isls., Kagoshima Prefecture were compared with populations from mainland Japan. Although size and shape variation of these island populations were within whole species range of variation, the size variation was less than that of some mainland populations. In contrast, canonical variate analysis showed a separation of the Yakushima population from other populations compared. Between these islands, skull shape was different, indicating that ecological difference such as prey size and abundance may exist. Island populations of M. itatsi could have been differentiated from mainland populations depending on different ecological conditions and geological history of each island.

Morphological variation of Transcaucasian chub, Squalius turcicus in southern Caspian Sea basin using geometric morphometric technique

This work was conducted to study the patterns of morphological differences in body shape in Squalius turcicus De Filippi, 1865 from the most east (Atrak River) to the most west (Aras River) populations of the southern Caspian Sea basin using landmark-based geometric morphometric method to understand how the body shape alters in relation to geographical alternations or environmental characters of their habitats. A total of 102 specimens were collected from the Aras, Tajan, Atrak, Ghareh-Su, Khyer and Sefid rivers and after anesthesia, their left faces were photographed. To extract shape data, 14 homologous landmark-points were digitized and data after generalized procrustes analysis, analysed using principal component analysis, canonical variate analysis, cluster analysis, and Mantel test. The results showed significant differences between the body shape of six studied populations, mostly related to snout, base of the dorsal and anal-fins, body depth and pectoral fin position as result of phenotypic plasticity to the environmental features of their habitats. The Tajan and Atrak populations have a higher and lower body depth, and the Kheyr population a longer snout.

Large‐scale dynamic process monitoring based on performance‐driven distributed canonical variate analysis

AbstractAs a typical process monitoring method for the large‐scale industrial process, the distributed principal components analysis (DPCA) needs to be improved because of its rough selection for the variables in each subblock. Moreover, for DPCA, the process dynamic property is ignored and invalid fault diagnosis may occur. Therefore, a performance‐driven distributed canonical variate analysis (DCVA) is proposed. Firstly, with historical fault information, the genetic algorithm is utilized to select appropriate variables for each subblock; secondly, canonical variate analysis is introduced to capture the dynamic information for performance improvement; finally, a novel fault diagnosis method is developed for the DCVA model. Case studies on a numerical example and the Tennessee Eastman benchmark process demonstrate the effectiveness of the proposed model.Highlights A novel fault diagnosis approach based on the distributed CVA model is presented. The dynamic property of process data for each sub‐block is firstly captured by CVA. With the genetic algorithm, the historical fault information is utilized to select appropriate variables in each sub‐block. The superiority of the developed method is validated on the numerical example and the TE process.

A Novel Geometric Morphometric Analytical Method for Classifying Mandibular Morphology in Infants With Isolated Pierre Robin Sequence

There is a lack of uniformity in the diagnostic criteria and system for the morphologic classification of micrognathia in infants with isolated Pierre Robin sequence (IPRS). Therefore, the aim of this study was to create a morphologic classification system for IPRS-affected mandibles that may guide surgical management and osteotomy design. We designed and implemented a retrospective cross-sectional study. The study sample included infants with IPRS. The predictor variables included shape variables of the IPRS-affected mandibles. The outcome of interest was morphologic differences among the IPRS-affected mandibles in the infancy stage. The original coordinate data of the mandibular images were analyzed by a generalized Procrustes analysis and 2-block partial least squares analysis to identify the focal and nonfocal areas in the IPRS-affected mandibles. The original feature points were modified according to the results of 2-block partial least squares analysis. The modified feature points were further analyzed by principal component analysis, K-means cluster analysis, and canonical variate analysis to obtain a morphologic classification of the IPRS-affected mandibles. One hundred fifty infants with IPRS were enrolled in this study. Principal component analysis showed that the variations among IPRS-affected mandibles were mostly in terms of the shapes of the mandibular ramus, mandibular body, and angle of the mandible. On the basis of the results of K-means cluster analysis and canonical variate analysis, the mandibles in group A3 showed characteristics such as a simply shorter mandibular body. Group B3 was adjusted to show characteristics such as a shorter mandibular body with a more obtuse mandibular angle, whereas group C3 showed characteristics such as a shorter mandibular body with a shorter mandibular ramus. Our study confirmed the hypothesis that there are quantifiable morphologic differences among the IPRS-affected mandibles, and it provided a morphologic classification of the IPRS-affected mandibles that will help to promote the clinical diagnosis and treatment.

Variable Sub-Region Canonical Variate Analysis for Dynamic Process Monitoring

When all process variables are used to establish one data-based model, some variables have little contributions to the model. When these variables are grouped into a small local variable set to develop a data-based model, their contributions will become large. It is called local variable characteristic. Standard canonical variate analysis (CVA) based process monitoring method doesn’t consider local process variable characteristic. To solve this problem, a variable sub-region based canonical variate analysis (V-CVA) is proposed for dynamic process monitoring by enhancing the information of local variables. The proposed method combines variable sub-region division and Bayesian fusion. First, standard CVA is performed by using all process variables. Then, K-means clustering is adopted to divide process variables into sub-regions based on the mutual information of process variables and canonical variables. For each variable sub-region, CVA is conducted to compute local process monitoring statistics. Finally, local statistics are fused to build ensemble statistics based on the idea of Bayesian inference. Compared with the standard CVA method, the proposed V-CVA method can emphasize the information of local variables, and has better monitoring performance in the canonical variable feature subspace and the prediction residual subspace. Two examples demonstrate the effectiveness of the proposed method.

Computational intelligence for studies on genetic diversity between genotypes of biomass sorghum

Abstract: The objective of this work was to evaluate the potential of computational intelligence and canonical variables for studies on the genetic diversity between biomass sorghum (Sorghum bicolor) genotypes. The experiments were carried out in the experimental field of Embrapa Milho e Sorgo, in the municipalities of Nova Porteirinha and Sete Lagoas, in the state of Minas Gerais, Brazil. The following traits were evaluated: days to flowering, plant height, fresh biomass yield, total dry biomass, and dry biomass yield. The study of genetic diversity was performed through the analysis of canonical variables. For the recognition of the organization pattern of genetic diversity, Kohonen’s self-organizing map was used. The use of canonical variables and a self-organizing map were efficient for the study of genetic diversity. The application of computational intelligence using a self-organized map is promising and efficient for studies on the genetic diversity between biomass sorghum genotypes.

Mashbill and barrel aging effects on the sensory and chemometric profiles of American whiskeys

American whiskeys are economically and culturally significant beverages with complex sensory profiles; however, how aromas and flavours are linked to mashbill (fermentedwash recipe) and/or aging time in new, charred oak barrels have not been thoroughly investigated. To accomplish this goal, sensory Descriptive Analysis and Chemometric analyses, including Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry and Liquid Chromatography-Quadrupole-Time-of-Flight-Mass Spectrometry, were conducted to evaluate American whiskeys distilled from controlled mashbills (two bourbons, two ryes) and aged in new, charred oak barrels from the same cooperage and stave lot. Data were analysed using M/ANOVA, Canonical Variate Analysis and Multiple Factor Analysis. The trained Descriptive Analysis panel evaluated all samples and developed a consensus attribute list. Panellists rated samples on 15-pt scales, in triplicate using a Williams Latin Square Design spread over 12 sessions to reduce presentation order effects. Descriptive Analysis results revealed that whiskey samples varied significantly in multivariate profiles and for 18 of 35 attributes by mashbill and aging time at bottling, but not by their interaction. Potentially positive whiskey attributes (e.g., vanilla and apples) are linked to increased aging times and higher corn content whereas other attributes (e.g., vegetal and hay/grassy) are correlated to shorter aging times. All analyses showed similar overall projections in the Multiple Factor Analysis for individual samples. Results from this study can help researchers, consumers, and distillers map sensory profiles of American whiskeys due to mashbill and aging time bottling. © 2020 The Institute of Brewing & Distilling

Morfometría geométrica de las alas permite verificar el posicionamiento racial de las abejas africanizadas

This study aimed to determine possible differences between populations of Africanized bees in the coastal area and of the sertão of Piauí, as a technique using geometric morphometry. The material analyzed consisted of adult workers of Africanized bees from the coastal region and of the sertão of Piauí. It was used as a comparative reference breeds digital images of the wings of 50 individual’s subspecies of European, African, and 45 individuals of Africanized bees coming from Ribeirao Preto in morphometric analyzes. In total we analyzed 645 images of wings. In the morphometric analysis, we used the standards veined right forewing with 19 landmarks. For the studies of geometric morphometric, the pieces were recorded and analyzed with the aid of programs and tpsDig MorphoJ. In the analysis of canonical variables, were the first three variables necessary to accumulate 86% of the total variation. There were significant differences (P &lt; 0.001) in multivariate analysis among the seven groups. The squared Mahalanobis distances were statistically significant. By geometric morphometrics of the wings could differentiate the subspecies evaluated and check the positioning of racial Africanized bees Piauí. There is evident the existence of ecotypes among bees littoral and hinterland Piauí.

Novel Pattern-Matching Integrated KCVA with Adaptive Rank-Order Morphological Filter and Its Application to Fault Diagnosis

With the scale expansion of industrial processes, the relationship between process variables becomes complex and highly nonlinear. As a result, the requirements for fault diagnosis and safety monitoring become demanding. To address this problem, a novel and effective pattern matching method using kernel canonical variate analysis (KCVA) integrated with an adaptive rank-order morphological filter (ARMF) is proposed for fault diagnosis. In the proposed method, KCVA is first used to extract the nonlinear correlation information with dynamic characteristics from the original process data and achieve feature dimension reduction; the features extracted by KCVA are then subjected to ARMF transformation for output trend features and pattern matching. To accurately evaluate the morphological similarity between the test trends and template trends of ARMF, the dynamic time warping distance is adopted for pattern classification. Finally, the proposed KCVA-ARMF pattern matching method is developed as an effective faul...

Landmark-Based Morphological Differences Among the Exotic Rhinogobius lindbergi and Its Two Sympatric Gobies (Actinopterygii: Perciformes: Gobiidae) in Sefid River, in the Southern Caspian Sea Basin

Introduced species may cause harm to native fish populations, which to design any conservative program to control the exotics an identification key is necessary. To find the morphological differences among the exotic Rhinogobius lindbergi and its sympatric congeners including the endemic Ponticla iranicus and the native Ponticla gorlap, a 15-landmark morphometric system was used to examine 90 specimens in Sefid River, in the Southern Caspian Sea basin. Univariate analysis of variance showed significant differences among the means of the three groups for 79 out of 105 standardized morphometric measurements. Principal component analysis (PCA) and canonical variates analysis (CVA) confirmed the statistically significant difference among these species. The CVA scatter plot showed that the 90 studied specimens grouped into three distinct areas with a degree of overlap between P. iranicus and P. gorlap. Clustering based on Euclidean distances among the groups of centroids using an UPGMA indicated segregation of the three species into two distinct clusters: P. iranicus and P. gorlap in one group and R. lindbergi in the other group. The exotic Rhinogobius can be distinguished from the sympatric gobies in Sefid River by short snout (vs. longer), deep body (vs. shallow), deeper head, stout body, and smaller ventral disc.

Path analysis and canonical variables of intervarietal maize hybrids

Maize (Zea mays L.) is the cereal most produced in the world, due to its wide scope and utilization in human and animal diet. This study aims to evaluate the agronomic performance of intervarietal maize hybrids, as well as the linear associations, interrelations of cause and effect, and the genotypes dispersion through canonical variates. The experiment was conducted in the agricultural year of 2014/2015. The crosses that originated the hybrids were carried out on the growing season of 2013/2014 and hybrids evaluated on 2014/2015. The hybrids were arranged in randomized blocks, being 13 treatments with five repetitions. The measured characters were: plant height, spike insertion height, stem diameter, spike diameter, spike length, spike mass, number of rows of grains per spike, number of grains per row, cob diameter, cob mass, spike grains mass, mass of a thousand grains, grain length and grain yield. The data were submitted to analysis of variance and mean values compared by the Tukey test at 5% of probability. The Pearson’s linear correlation analysis and path analysis were performed using grain yield as a dependent character. Furthermore, the analysis of canonical variables was carried out. The hybrid H5: G3 X G4 revealed higher grain yield, spike grains mass, number of grains per row and spike diameter. Grain yield of intervarietal hybrids presented positive correlations with the traits such as stem diameter, spike diameter, spike length, number of grains per row, mass of a thousand grains, grain length and spike grains mass. Spike diameter and spike length presented higher direct effects on grain yield of intervarietal hybrids. The canonical variates revealed the formation of five phenotypically distinct groups of intervarietal hybrids.

Geometric morphometrics of leaves of Cynanchum acutum L. (Apocynaceae) from Egypt

This study aimed to revise Cynanchum acutum in Egypt and their relative subspecies that belonging to Section Cynanchum (Old World) and comparing it with an American group of genera Cynanchum laeve subgen. (Sect.) Mellichampia (New World) by using classical taxonomy and Modern geometric morphometric methods (GMMs). The description of 85 specimens depending on 36 quantitative traits was measured on each of the leaves using ImageJ Tool software. Data of leaf descriptors was further processed by using R program. Heatmap appeared to be more fluctuating between two color levels indicated to the similarity and dissimilarity between taxa and population, likewise, a PCA biplot showed a total variation 37.7% at first axis and 8.9% at the second. Significant variation in taxa and populations estimated using ANOVA and MANOVA. Canonical variate analysis showed a significant difference between taxa (P=0.001***), with a total variation of 67% between three taxa. The total variation Checked between two taxa by using discriminant analysis, C. acutum subsp. acutum and C. acutum subsp. sibiricum calculated 77% variation, while as the total variation between then between C. acutum subsp. acutum and C. laeve show 86% of the variation and significant value (P=0.002**). The study elucidated the situation of Cynanchum acutum in Egypt and confirmed the presence of two subspecies viz.: subsp. acutum and subsp. sibiricum

Three-dimensional analysis of the human pharyngoesophageal sphincter.

Dysfunction of the pharyngoesophageal segment (PES) is a common cause of oropharyngeal dysphagia. Surgical dilation of the PES uses cylindrical dilators that expand radially in a circular shape. Animal studies, however, suggest that the PES is kidney-shaped. The purpose of this investigation was to evaluate the 3D shape of the human PES with a novel casting method. A platinum-cured liquid silicone polymer was infused under pressure into the upper aerodigestive tract of nine fresh human cadavers to construct 3D casts of the maximally distended PES. Cross-sectional and volumetric analysis were performed using computed tomography and serial sectioning of the models. Canonical variate analysis was used to identify the shape features that best distinguishes the PES from the cervical esophagus. The mean age of the cadavers was 77.9 (SD ± 10.6) years, with 67% women. Analysis of the casts confirms that the human PES possesses a kidney-shaped structure at maximal distention, which is discretely different from the adjacent esophagus (P < 0.001). The posterior body of the cricoid cartilage formed the anterior wall of the PES, which provided a rigid structure responsible for preservation of the kidney shape during distention. The diameter of the maximally distended PES at the cricopharyngeus was highly variable (range = 0.86-4.68 cm2 ; SD = 1.33 cm2 ). The data suggest that the human PES is not round and that targeted expansion at the level of the cricopharyngeus with an eccentrically shaped dilator may provide improved distention. 4 Laryngoscope, 2019.

Craniofacial geometric morphometrics in the identification of patients with sickle cell anemia and sickle cell trait.

ObjectiveThe aims of this study were to identify the main characteristics regarding the shape and size of the craniofacial region in patients with sickle cell anemia (SCA) and sickle cell trait (SCT) and in unaffected patients using geometric morphometrics and to check the efficiency of this method.Material and MethodsA cross-sectional analytical study of 45 patients (15 in each group) was performed. Lateral radiographs of the skull were used for the analysis. Seventeen landmarks and semilandmarks were placed for the measurements. The Pocrustes analysis of variance (ANOVA), regression analysis, multivariate analysis of variance, canonical variate analysis, Mahalanobis and Procrustes distances and unweighted pair group method with arithmetic mean (UPGMA) clustering were performed. Allometric effects and sex characteristics were not statistically significant (p > 0.05).ResultsThere were, however, significant differences (p < 0.05) in craniofacial shape among SCA, SCT and unaffected individuals. Those with SCA showed variations in the shape of the external auditory meatus and at the base of the occipital bone, in addition to the mandibular setback and upper incisor inclination, with a tendency towards prognathism. The individuals with SCT exhibited a similar craniofacial shape to those with SCA, but with slighter variations. Moreover, those with SCT were statistically closer in resemblance to unaffected individuals, given that SCT is not regarded as a disease.ConclusionThis demonstrates the efficiency of geometric morphometrics in the categorization of the assessed groups.