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Objective: Anopheles maculatus is recognized as an important malaria vector in Thailand and other countries within the Greater Mekong Subregion. This study employed both landmark and outline-based geometric morphometrics (GM) approaches to assess seasonal variation in the wing structure and wing contour of A. maculatus from malaria hotspots in western Thailand across three seasons: hot, wet, and dry. Materials and Methods: We analyzed seasonal variation in wing structure and contour using landmark-based and outline-based GM approaches, respectively, applied to the same image set of wing samples. Statistical differences in size and shape among seasonal populations were evaluated using a non-parametric analysis of variance (1,000 replicates), followed by a Bonferroni post hoc test. A p-value of less than 0.05 was used as the criterion for statistical significance in all analyses. Results: The size analyses revealed a significant difference in wing structure between the hot and dry seasons (p < 0.05), while no significant differences (p > 0.05) in wing contour across seasonal populations were detected. Significant differences (p < 0.05) in wing structure based on shape were detected between A. maculatus populations in the dry and hot seasons, as well as between populations in the dry and wet seasons. Wing contour analysis based on shape showed a significant difference (p < 0.05) only between the populations from the dry and wet seasons. Conclusion: These findings provide us with valuable information about the seasonal adaptation of A. maculatus, thus enhancing our understanding of vector population dynamics and potentially improving malaria surveillance strategies.

Recent studies have identified wing cells, a substructure of the wing, as carrying taxonomic signals across various mosquito genera. However, the presence of a taxonomic signal in the wing cells of the genus Lutzia (Diptera: Culicidae) has not yet been confirmed. Objective: This study aimed to evaluate the efficacy of the outline-based geometric morphometric (GM) approach in distinguishing Lutzia species found in Thailand, namely Lutzia chiangmaiensis, Lutzia fuscana, Lutzia halifaxii, and Lutzia vorax. Materials and Methods: The outline-based geometric morphometrics was employed to analyze four wing elements: the wing contour, the second submarginal cell, the first posterior cell, and the third posterior cell. Results: In the size analysis, Lt. vorax consistently exhibited significantly larger wing elements compared to the other species (p < 0.05). The factor maps based on discriminant analysis for the wing elements among the species indicated that most groups overlapped in morphospace. However, for the third posterior cell, the Lt. vorax group presented a more distinct shape. While shape analysis detected significant differences between almost all species pairs (p < 0.05), there was an exception between Lt. halifaxii and Lt. chiangmaiensis in the first posterior cell (p > 0.05). Additionally, shape analysis further indicated that the third posterior cell achieved the highest percentage of correct classifications, with an adjusted total assignment accuracy of 71%. Conclusion: This finding reveals a significant taxonomic signal in the third posterior cell, suggesting that the outline-based GM approach can effectively complement the landmark-based GM approach in distinguishing Lutzia species.

Invasive species can encounter environments different from their source populations, which may trigger rapid adaptive changes after introduction (niche shift hypothesis). To test this hypothesis, we investigated whether postintroduction evolution is correlated with contrasting environmental conditions between the European invasive and source ranges in the Asian tiger mosquito Aedes albopictus. The comparison of environmental niches occupied in European and source population ranges revealed more than 96% overlap between invasive and source niches, supporting niche conservatism. However, we found evidence for postintroduction genetic evolution by reanalyzing a published ddRADseq genomic dataset from 90 European invasive populations using genotype–environment association (GEA) methods and generalized dissimilarity modeling (GDM). Three loci, among which a putative heat-shock protein, exhibited significant allelic turnover along the gradient of winter precipitation that could be associated with ongoing range expansion. Wing morphometric traits weakly correlated with environmental gradients within Europe, but wing size differed between invasive and source populations located in different climatic areas. Niche similarities between source and invasive ranges might have facilitated the establishment of populations. Nonetheless, we found evidence for environmental-induced adaptive changes after introduction. The ability to rapidly evolve observed in invasive populations (genetic shift) together with a large proportion of unfilled potential suitable areas (80%) pave the way to further spread of Ae. albopictus in Europe.

Only recently has the use of 3D-scanning technology enhanced our ability to consider shape using landmark approaches to geometric morphometrics (GM). Studies examining several types of anthropological datasets have provided mixed reviews of the utility of the third dimension in landmark GM shape analyses. In this paper we present the results of a study examining the methodological utility of three dimensions in landmark GM shape analysis of prehistoric stone points. We used GM to generate principal components (PCs) of shape variation from independent data sets of Clovis and Dalton points in different shape spaces using 2D and 3D versions of the same sample and examined variation in the distribution of shape variables on PCs generated for each data set. Results of uniform multivariate statistical tests performed on each dataset’s PCs were compared to observe whether 2D or 3D data is more effective at determining group membership. We then generated PCs of shape variation in the same shape space using dependent 2D and 3D datasets to observe whether 2D versions of the data cluster with corresponding 3D versions of each point in a PC biplot and multivariate cluster analysis. Results suggest that 2D GM analysis is as capable of discriminating between Clovis and Dalton points as analyses conducted with 3D data. However, those interested in manufacturing technology will benefit from information provided by 3D data sets, which can capture information such as original blank form and thinning strategies.

Cut marks are striae accidentally produced by the contact made between the edge of a cutting tool and bone surfaces by anthropogenic activity, presenting evidence of hominin carcass processing and behaviour, butchery activities or diet. Post-depositional processes can cause the alteration (chemical or mechanical) of bones surfaces, changing their composition and causing the modification of bone surfaces. Previous research has addressed the problem of chemical alteration from a qualitative perspective, resulting in the loss of all diagnostic characteristics of the cut marks affected by these processes. Geometrics Morphometrics has led to great progress in the study of cut marks from a quantitative perspective and can be useful for the study of altered cut marks. In this study, an experiment was carried out in which 36 cut marks were reproduced and chemically altered. These marks were scanned and digitized before and after each phase of alteration. They were analyzed metrically as well as using Geometric Morphometrics, in order to study the evolution of modifications to cut mark morphology during the experiment. Results show clear morphological differences between the different phases of alteration with altered cut marks presenting a general tendency towards a decrease in both the width and depth over time. Research of this type opens up a new path for the study of the chemical alteration of cut marks, as well as other striae, through the application of Geometric Morphometrics.

Background: The characterization of facial sexual dimorphic patterns in healthy populations serves as valuable normative data to tailor functionally effective surgical treatments and predict their aesthetic outcomes and to identify dysmorphic facial traits related to hormonal disorders and genetic syndromes. Although the analysis of facial sexual differences in juveniles of different ages has already been investigated, few studies have approached this topic with three-dimensional (3D) geometric morphometric (GMM) analysis, whose interpretation may add important clinical insight to the current understanding. This study aims to investigate the location and extent of facial sexual variations in juveniles through a spatially dense GMM analysis. Methods: We investigated 3D stereophotogrammetric facial scans of 304 healthy Italians aged 3 to 18 years old (149 males, 155 females) and categorized into four different age groups: early childhood (3–6 years), late childhood (7–12 years), puberty (13–15 years), and adolescence (16–18 years). Geometric morphometric analyses of facial shape (allometry, general Procrustes analysis, Principal Component Analysis, Procrustes distance, and Partial Least Square Regression) were conducted to detail sexually dimorphic traits in each age group. Results: The findings confirmed that males have larger faces than females of the same age, and significant differences in facial shape between the two sexes exist in all age groups. Juveniles start to express sexual dimorphism from 3 years, even though biological sex becomes a predictor of facial soft tissue morphology from the 7th year of life, with males displaying more protrusive medial facial features and females showing more outwardly placed cheeks and eyes. Conclusions: We provided a detailed characterization of facial change trajectories in the two sexes along four age classes, and the provided data can be valuable for several clinical disciplines dealing with the craniofacial region. Our results may serve as comparative data in the early diagnosis of craniofacial abnormalities and alterations, as a reference in the planning of personalized surgical and orthodontic treatments and their outcomes evaluation, as well as in several forensic applications such as the prediction of the face of missing juveniles.

The wing geometric morphometrics (WGM) is a powerful method for identifying variation within species and differentiating from other species. Therefore, this research aimed to determine the wing geometric variation in Cx. tritaeniorhynchus from different locations and also compared it to the wing geometry of the highly resemble species of Cx. vishnui. A total of 54 females of Cx. tritaeniorhynchus from Ende Regency (Wologai and Nanganesa) and Konawe Regency (Tamesandi and Puuhopa) were collected, while 34 females of Cx. vishnui were collected from nearest locations (Mautapaga, Ende Regency, and Bajo Indah, Konawe Regency). In addition, 17 females of Aedes aegypti were also used in the analysis representing species outside the Genus Culex as an outgroup. After being photographed, the wing was marked to create landmarks (LMs) using the tpsUtil 1.70 and tpsDig2 2.29 software series. The LMs were superimposed using the Procrustes Fit function and the canonical variate analysis (CVA) was performed with MorphoJ 1.06d software, and the Mahalobis distance matrix and the dendrogram (unweighted squared-change parsimony with 10.000x permutations) were subsequently generated. The result demonstrated that the intraspecies geographical variation on the wing geometry occurred in Cx. tritaeniorhynchus. Further, WGM also could distinguish Cx. tritaeniorhynchus apart from Cx. vishnui. The statistical analysis has marked out that the geometrical variation in Cx. tritaeniorhynchus wing can be utilized to distinguish different populations from different geographical areas. The feature could also be a tool to differentiate Cx. tritaeniorhynchus from Cx. vishnui.

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.

This study aimed to compare the morphological characteristics of northern Caucasian bleak (Alburnus hohenackeri) populations in the Caspian basin using geometric morphometrics. Geometric morphometrics in fishes examines the changes in their appearance among different groups or under different environmental conditions by using anatomical reference points on their body. The data encompassed 487 fish samples from the Caspian Basin, including the Aras, Shalmanrud, Mazoboon, Noor, Sorkhrud, Goharrud, Kaparbordrud 1, Kaparbordrud 2, Gorganrud 1, Gorganrud 2, Lamir, and Hajibakandeh rivers. Photographs were taken from the left side of the lateral surface of these samples, and then 13 landmarks were digitized using tpsDig2 software. The data obtained from Procrustes analysis were analyzed with multivariate statistical methods such as PCA, CVA, and cluster analysis. The comparison of geometric morphometrics revealed a significant difference between the Aras River population and the other populations. The main differences were related to the shape of the body, the size and shape of the head, the position of the mouth, the position of the fins, the height of the body, and the length of the tail stem. This difference between the Aras River population and other rivers may be due to variations in habitat and geographical separation. Alternatively, it is possible that the observed differences indicate distinct species. On the other hand, the other populations overlapped with each other, and no significant difference was observed between them. This similarity in morphometrics could be attributed to similar habitat conditions. Keywords: Geometric morphometric, Principal Component Analysis, Canonical Variate Analysis, Procrustes Analysis. Introduction The Caucasian bleak (Alburnus hohenackeri), belonging to the Leuciscidae family, is commonly found among aquatic plants in the lower parts of rivers and freshwater lakes. It can tolerate brackish water to some extent and is most abundant in river estuaries. This species inhabits all ecosystems of the Caspian Sea, although human activities have inadvertently introduced it to other water bodies like Zarivar, Maraveh, Hamun, and Sistan. Habitat and river differences significantly impact fish species, making morphological studies of Caucasian sprat across various rivers and water bodies important. Morphological characteristics are essential for differentiating populations within a species and can provide insights into evolution, behavior, conservation, and resource utilization (Nacua et al. 2010; Su et al. 2019). The geometric morphometric method based on landmarks is widely applicable in biological studies and is effective in analyzing morphological changes over time and space (Klingenberg 2017; Adams et al. 2004). This method allows for comparisons between biological forms based on landmark coordinates, which can be visualized in a deformation network. Understanding fish in aquatic ecosystems is crucial from ecological, behavioral, evolutionary, and resource management perspectives (Razavipoor et al. 2014). The primary aim of this study is to investigate the geometric morphological differences of Caucasian sprat within the Caspian Sea basin, which is the largest lake globally, housing around 115 fish species, including economically and ecologically significant species like sturgeon, mullet, carp, and trout (Ghojoghi et al. 2018). Materials and Methods In this study, 487 specimens of Caucasian sprat (from a total of 12 populations across 12 rivers) were collected from the Caspian Sea basin between 2009 and 2010. The identification was based on the 2020 checklist (Jouladeh-Roudbar et al. 2020). The fish studied were not mature, making sex determination impossible; therefore, they were analyzed as a mixed group. However, the samples were sufficiently grown for identification. Some samples were excluded from the study due to inadequate growth for identification, and only recognizable specimens were included. The fish mature at a size of 12 cm, while the specimens studied ranged from 8 to 11 cm. After selecting the target rivers for sampling, Caucasian sprat specimens were captured using a seine net and an electrofishing device. The samples were then fixed in 10% neutral buffered formalin and transferred to the Ichthyology Laboratory of the Faculty of Natural Resources at Isfahan University of Technology, where they were preserved in 70% alcohol. Geometric morphometric data were extracted using a 14-megapixel Canon digital camera (made in Japan). Landmarks were placed on the images using TpsDig2 software (version 2.10). Morphometric data for the studied species were compared using Tps series software (version 2). Procrustes analysis was used to eliminate non-shape variations, followed by analysis using PAST software (version 2.17). The average shape changes of populations were derived from the overall mean shape. Geometric morphometric data were analyzed using principal component analysis and canonical variable analysis. Figure 2 illustrates a fish sample for landmark determination. Research Findings The results of principal component analysis (PCA) indicated that the first three components were selected as the main factors distinguishing the populations, accounting for approximately 53% of the total variance. The distribution of the studied populations and changes in body shape along the first two principal components were analyzed. The analysis revealed that eleven populations overlapped, indicating no significant differences among them. However, the Aras River population did not overlap with the others, showing significant differences. Changes in body shape patterns indicated that movement in the positive direction of the first principal component was associated with alterations in mouth position, shifts in eye positions, and significant changes in dorsal fin positions, pelvic and anal fin positions, as well as increases in body height and caudal peduncle length. In the positive direction of the second principal component, similar changes were observed, including downward movement of the mouth, shifts in the head end position, alterations in dorsal and anal fin positions, and increases in body height and caudal peduncle length. Canonical correlation analysis demonstrated that nearly all populations overlapped with no significant differences, except for the Aras River population, which was distinct from the others. Cluster analysis indicated that the Aras River population formed a separate branch, showing the greatest distinction from other populations. Two main groups emerged: one including the Aras River and another with the remaining populations. Within the second group, the Marzbon population was notably distinct, while the pairs of populations Golestanrud1 and Haji-Bakandeh, as well as Koper-Bardrud1 and Noor, were identified as sister populations with minimal distance between them. Discussion of Results & Conclusion Fish populations in different habitats exhibit distinct forms due to environmental conditions. Among vertebrates, fish show a high degree of morphological diversity and sensitivity to environmental changes (Mouludi-Saleh et al. 2018). While shape variations were once thought to be primarily genetic, it is now recognized that environmental factors play a crucial role. Numerous studies have demonstrated that body shape correlates with specific environmental conditions, leading to notable adaptations. For instance, research in the southern Caspian Sea basin identified traits such as head size, body depth, and fin positions as key factors distinguishing fish populations (Mouludi-Saleh & Keivany 2019). Similarly, studies on narrow-nosed mullet and stream catfish revealed significant morphological variations influenced by their habitats (Abassi et al. 2023a; Sharifinia & Mousavi 2016). Morphological changes are significant when linked to functional aspects, such as foraging behavior and movement efficiency in aquatic ecosystems (Abassi et al. 2023b). For example, a downward mouth position in the Aras population may indicate feeding from deeper waters, while reduced body height may aid in navigating currents (Hawkins & Quinn 1996). Overall, the evolutionary changes leading to morphological differences in the Aras population appear to be influenced by habitat characteristics and geographical isolation. The distinct shape of the Aras population likely relates to its dietary habits and environmental adaptations, impacting its feeding success and predator avoidance (Langerhans et al. 2003).

Although dose-response analyses are a fundamental tool in developmental toxicology, few studies have examined the impacts of toxicant dose on the non-genetic paternal inheritance of offspring disease and dysgenesis. In this study, we used geometric morphometric analyses to examine the impacts of different levels of preconception paternal alcohol exposure on offspring craniofacial shape and symmetry in a mouse model. Procrustes ANOVA followed by canonical variant analysis of geometric facial relationships revealed that Low-, Medium-, and High-dose treatments each induced distinct changes in craniofacial shape and symmetry. Our analyses identified a dose threshold between 1.543 and 2.321 g/kg/day. Below this threshold, preconception paternal alcohol exposure induced changes in facial shape, including a right shift in facial features. In contrast, above this threshold, paternal exposures caused shifts in both shape and center, disrupting facial symmetry. Consistent with previous clinical studies, changes in craniofacial shape predominantly mapped to regions in the lower portion of the face, including the mandible (lower jaw) and maxilla (upper jaw). Notably, high-dose exposures also impacted the positioning of the right eye. Our studies reveal that paternal alcohol use may be an unrecognized factor contributing to the incidence and severity of alcohol-related craniofacial defects, complicating diagnostics of fetal alcohol spectrum disorders.