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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.

This study used 3D landmark-based geometric morphometrics under an object-symmetry framework to quantify pelvic asymmetry in domestic cats and dogs while explicitly accounting for measurement error through replicate digitizations. Procrustes ANOVA revealed significant components of both directional asymmetry (DA) and fluctuating asymmetry (FA) in the overall dataset, and DA was further visualized as a structured, non-random pattern across the landmark configuration. Measurement error remained smaller than the FA component, yielding high repeatability, indicating that the detected asymmetry patterns were not driven by landmarking imprecision. Group-wise summaries are presented as descriptive patterns of the sample (rather than direct between-group inference). In these descriptive summaries, cats tended to show a more coherent DA pattern, whereas dogs showed greater individual variation consistent with a relatively stronger FA component; males also tended to exhibit greater FA-related dispersion than females. In regression models of FA, age showed no association, body mass exhibited only a weak trend, and sex emerged as a significant predictor, while species showed no detectable effect when covariates were included. Collectively, these results support the hypothesis that pelvic shape contains both systematic (DA) and individual-specific (FA) asymmetry components, with sex-related differences in FA magnitude, but limited evidence for age- or weight-related effects within the sampled range. The study provides a repeatable framework and baseline reference for pelvic asymmetry in cats and dogs.

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.

The genus Delminichthys consists of allopatric species restricted to ephemeral watercourses in the karst fields of the left-bank (D. ghetaldii) and the right-bank (D. adspersus and D. jadovensis) Neretva River basin as well as in the Una River drainage (D. krbavensis). The first aim addressed questions of interspecies variation and phylogenetic relationships among Delminichthys based on time-calibrated analysis of cyt b mtDNA (cytochrome b) and COI mtDNA (cytochrome c subunit I) mitochondrial DNA genes. Species-specific haplogroups supported two mtDNA genes as suitable barcoding markers, while we additionally proposed character-based and genetic distance threshold-based delimitation of species. We confirmed that the Pliocene and Pleistocene refugium for freshwater species was the Neretva basin, promoting the diversification of the genus Delminichthys. Our second aim was to test the population structure of D. ghetaldii (Southern Dalmatian minnow) by performing an integrative study using molecular mtDNA data, linear and geometric morphometric data. We consider that the spatial aspects of the population genealogical structure of D. ghetaldii mirror the Pleistocene paleodrainages. The differentiated COI mtDNA clusters corresponding to the populations from Fatničko Polje+Dabarsko Polje and Ljubomirsko Polje+Konavosko Polje represent geographically discrete genetic entities, which should be addressed through conservation management.

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.

“Placoderm” and sarcopterygian fishes dominated Devonian waters. Following the end-Devonian crisis, actinopterygians rapidly became major contributors to vertebrate diversity. This transition constitutes the first major diversification event of actinopterygians. Here, we investigate the morphological diversification of Devonian and Carboniferous actinopterygians by quantifying disparity using two-dimensional (2D) geometric morphometrics, which estimates disparity from continuous data and brings geometric information related to the shape changes in several morphological features. In total, 13 landmarks and 203 semi-landmarks were digitized on the body shape reconstructions of 84 species, and 18 landmarks and 50 semi-landmarks were digitized on the reconstructions of the lateral view of the skulls of 86 species. When compared to variations in taxonomic diversity over time, the pattern of body shape variations is congruent, reaching a maximum during the Viséan, but the pattern of skull disparity is not entirely congruent, presenting a first increase during the Late Devonian. Changes in body shape are associated with locomotory properties, while changes in skull shape are associated with functional properties of the feeding apparatus. This pattern strongly suggests the diversification of actinopterygians to be driven by divergence in trophic strategies. This evolutionary radiation seems to be the result of an adaptive response to new ecological opportunities, triggered by big environmental changes in mid-Paleozoic oceans.

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.