Terrestrial tetrapods originated during the Middle Devonian, and the group rapidly diversified throughout the subsequent Carboniferous and Permian periods. Feeding in air rather than water is expected to require changes to tetrapod mandibular form and function. Previous biomechanical studies on jaw evolution, however, found that the increase in functional disparity lagged behind terrestrialisation by approximately 70 Myr, coinciding with the origin of amniotes and herbivory. We expand on a previous dataset composed primarily of non-amniote tetrapods to identify the drivers of this diversification, including representatives of all major amniote clades from the Permo-Carboniferous. First, we measured nine biomechanical traits from 111 tetrapod jaws in medial view. Second, we performed an Elliptical Fourier Analysis on 198 jaws in lateral view and 73 jaws in occlusal view. The first peak in jaw disparity, during the Pennsylvanian, occurs in carnivorous non-amniote tetrapods. However, the jaws of amniotes, particularly those inferred as herbivorous, are consistently more disparate than non-amniote tetrapods from the early Permian, especially in terms of jaw depth, symphysial length and force transmission. Functional and shape disparity of Palaeozoic tetrapod jaws follow a similar pattern that is explained by large-scale faunal turnovers and ecosystem structures.

Prediction of fruit shapes in F1 progenies of chili peppers (Capsicum annuum) based on parental image data using elliptic Fourier analysis

Machine vision/image analysis is used in the sorting and handling of many aquatic species. Pictures of 474 New Zealand Greenshell™ (Perna canaliculus, Gmelin, 1791) whole unopened mussels (215 females and 259 males) from the top and from the side were analyzed to evaluate if visual attributes (size, shape, and color) can be used to differentiate gender. Size (length, width, height, and view area), color, and shape (by elliptic Fourier analysis and by ray length-ray angle analysis) were analyzed and differences by gender tested. Application of Artificial Neural Networks (ANN), Principal Component Analysis (PCA), Canonical Discriminant Analysis (CDA), and Random Forest (RF) to the shape parameters failed to reliably predict gender. Comprehensive morphometric and color characterization of males and females, as well as shape parameters, are presented as a reference for future image-based research. The parasitic crustacean pea crab can change the shape of mussel shells, and elliptic Fourier analysis can quantify this difference.

The evolution of wings and flapping flight was integral to the radiation of Pterygota, but little is known about the factors underpinning the morphological disparity of insect wings. We use a theoretical morphospace approach to investigate forewing morphology across the four major clades in Hymenoptera (sawflies, wasps, bees and ants). Using elliptical Fourier analysis we quantified the outline of 298 forewings and generated 494 theoretical forms plotted within a morphospace. Theoretical forewing shapes were analysed across three metrics for flight performance that are antagonistic and ranked subsequently according to their functional optimization. The results show theoretical wings with larger, rounder apical tips were most optimized for a trade-off between reducing induced drag and increasing both lift production and breakage resistance. Empirical forewings cluster in a suboptimal region of theoretical morphospace exhibiting moderate flight performance. Phylomorphospace analysis reveals high levels of convergence in wing shapes across Hymenoptera, with a weak but significant phylogenetic signal. Regression analyses found significant allometric covariation but no significant relationship with environmental measures (temperature and precipitation) on forewing morphology. These findings demonstrate that hymenopteran wing morphologies are not optimized for flight function. Instead, function and allometry act in concert to constrain the variation of hymenopteran forewing morphologies.

ABSTRACTThe accurate classification of hazelnut cultivars is critical for ensuring product consistency, quality control, and market competitiveness in the food industry. Conventional identification methods remain manual, time‐consuming, and error‐prone, highlighting the need for automated alternatives. This study presents a novel, real‐time machine vision system for classifying 11 hazelnut cultivars using a single side‐view image. The proposed approach integrates three complementary feature extraction techniques: Elliptical Fourier Analysis (EFA) for contour and shape decomposition, circular masking for curvature quantification, and brown color gradient analysis for surface tone assessment. The extracted features—fully normalized and dimensionless to account for variations in imaging angle, distance, and nut positioning—were classified using three machine learning algorithms: Support Vector Machine with Radial Basis Function (SVM‐RBF), Multilayer Perceptron (MLP), and Extreme Learning Machine (ELM‐RBF). Among the classifiers, SVM‐RBF achieved the highest performance with an F1‐score of 0.92 for multi‐view images and 0.89 for side‐view only. MLP and ELM‐RBF followed with competitive yet slightly lower scores. The system demonstrated high robustness, computational efficiency, and interpretability. Overall, the proposed method offers a lightweight, scalable, and non‐destructive solution for hazelnut cultivar classification and demonstrates strong potential for real‐time deployment in industrial sorting lines and embedded systems in precision agriculture.

Photo identification (photo ID) has increasingly become a valuable technique serving not only to identify individual animals but also to monitor populations, track migration patterns and assess wildlife health, among others uses. Various species of sharks are amenable to photo ID, among which the blacktip reef shark (Carcharhinus melanopterus) is a particularly suitable subject. Their distinctive pigmentation and dorsal‐fin patterns serve as potential key identifying features. This study focuses on the variation in dorsal‐fin patterns among individual neonatal and juvenile C. melanopterus around Moorea, French Polynesia. We employed a Gower distance matrix to assess dissimilarities in dorsal‐fin patterns and conducted an elliptical Fourier analysis (EFA) to characterize shape variations. The results from the EFA were further summarized using principal component analyses. Additionally, we explored the potential symmetry between the left and right sides of the dorsal fin. To assess the long‐term reliability of using pigmentation patterns for photo ID, dorsal‐fin patterns of recaptured individuals were compared using regressions of log‐transformed dorsal‐fin measurements over log‐transformed pre‐caudal lengths. Recaptures occurred over varying time frames, ranging from as short as 2 weeks to as long as 9 months. The diverse range allowed us to evaluate the temporal stability of dorsal‐fin patterns across different intervals. The analyses revealed that each individual shark's dorsal‐fin pattern is unique, but the left and right sides are asymmetrical. Regarding the analysis of recaptured individuals, the ontogenetic changes in dorsal‐fin size were not significant enough to alter the dorsal‐fin patterns, thus ensuring their temporal stability. The application of photo ID techniques, as demonstrated in this study, underscores its indispensable role in conservation strategies, promoting a deeper understanding of elasmobranch species.

Abstract Chillies are one of the most cultivated plants in the world. The species of the genus Capsicum have a wide range of uses in agriculture, as vegetables and spices, in medicine and as ornamental plants. In Colombia, chilli represents an important exported crop, but the morphological characterization of this genetic resource is still poor. In this way, the Elliptic Fourier Analysis (EFA) is a value tool to evaluate the morphological variation of any group as allow the application of geometric morphometric to structures that do not have homologous points or are difficult to assign as chili fruits. For this purpose, fruits from the departments of Cauca, Nariño and Valle del Cauca were collected in marketplaces, gardens and natural reserves. The accessions were identified based on morphological and molecular characteristics. Photos of each fruit were taken, digitized and used to obtain the coordinates of the fruit outline to perform an EFA. With the coefficients obtained from the EFA, a principal components analysis (PCA) and a clustering analysis were performed. Finally, a discriminant analysis was performed to differentiate the fruit outline of two Capsicum species. A total of 743 pepper fruits were collected, representing 160 accessions and 5 species (C. annuum, C. frustescens, C. chinense, C. pubescens and C. baccatum). Cluster analysis revealed five representative fruit shapes: long and curved, conical, asymmetrical conical, round and triangular. The wild accessions had round fruits, while the domesticated accessions had triangular, conical, asymmetrical conical and curved fruits. The discriminatory analysis made it possible to distinguish between C. annuum var. glabriusculum and C. frutescens wild, species that are difficult to identify on the basis of other morphological characters.

Parasitengona, an ingroup of Trombidiformes, is characterised by a complex life cycle, in which the larval stage is parasitic on animals. Larvae of erythraeoideans or long-legged velvet mites, one ingroup of Parasitengona, parasitise euarthropodan hosts and have extremely long legs that confer them the ability to walk fast. Representatives of Parasitengona in general, and Erythraeoidea in particular, are relatively abundant in the fossil record. Nonetheless, their studies have remained scarce, since, like in most mites, the characters needed for taxonomical identification are hidden within the amber piece. Here, we report 41 new erythraeoidean larvae from the Cretaceous Kachin amber and three specimens from Eocene Baltic amber. We also compare the shape of their habitus between extant and fossil specimens by applying elliptical Fourier analysis (EFA) to their redrawn outlines. According to the shape analysis, there is a certain level of overlap in the morphospace between extant and fossil specimens, but the difference in morphology was statistically significant, pointing to a separation between the two. This is supported by the fact that some morphological characteristics of fossil specimens are not present in extant representatives. Fossil erythraeoideans occupy the area of the morphospace with more elongated legs, which could be related to variations in the availability of their hosts or changes in microhabitat occupied by the mites, although bias in the fossil record cannot be ignored. Although preliminary, our findings demonstrate that quantitative morphological analysis can be applied to specimens of mites not preserved in the best of conditions that may not be of interest for taxonomic studies.

Abstract Overexploitation and unregulated trading of Lapnisan (Aquilaria species) has been reported in Mount Hamiguitan Range and Wildlife Sanctuary. Hence, the conduct of the study using Elliptic Fourier Analysis (EFA) to describe variation in leaf outlines of the Aquilaria species and its associated flora to determine the ecologically important species that requires conservation and protection. A Line plot method was established in 150-meter transect lines, and 20 x 20 m plot was laid out. On the identified Aquilaria, thirty (30) fully expanded leaves per individual were collected from non-damaged mature individuals. The digital images of the fresh leaves were made using a Brother Scanner and saved in a bitmap format. Using a software package SHAPE ver. 1.3, the outline-based morphology of the leaves were analyzed based on Elliptic Fourier Descriptors (EFD) to resolve taxonomic problems. The study revealed that Shorea polysperma (Blanco) Merr. in Barangay La Union and Palaquium species in Barangay Maputi dominated the study areas. This served as keystone species and suggest ecological interactions in forest dynamics for Aquilaria to grow in its natural habitat. Furthermore, the study revealed that MHRWS has a moderate floristic diversity index along Barangay La Union with 2.98 and Barangay Maputi with 2.93. Thus, giving a clear resolution that the leaf shape can be used to discriminate between the two Aquilaria species, and the area needs to protect vulnerable, least concern, endangered, endemic, and indigenous species for in situ conservation as a rapid identification tool for law enforcement against illegal cutting and trade‥

Genus Argyreia belongs to the family Convolvulaceae and comprises flowering plants commonly known as silvervine or elephant creeper. These plants are native to tropical and subtropical regions, including parts of Africa, Asia, and Australia. Argyreia species are known for their large, attractive flowers and are often cultivated for ornamental purposes. Argyreia plants typically have simple and alternate, large, broad leaves. The leaves can vary in shape, often being ovate or cordate, and have prominent veins. Morphometric analysis of the leaves of eight (8) species of the genus Argyreia was carried out using Elliptic Fourier Analysis (EFA). Principal component analysis (PCA) was performed based on variance-covariance matrix. Resulting PCs are utilized to create a dendrogram via neighbour joining method using Euclidean distance. The dendrogram revealed three major groups among the presently analysed species of Argyreia. Group-I was comprised of four species i.e., A. pilosa, A. nervosa, A. boseana and A. sharadchandrajii. A. setosa, A. sericea and A. elliptica formed the second group. Due to different leaf shape A. cuneata has been placed in last group. Present study reveals the importance of morphometric analysis in species differentiation based on leaf shape and structure and can be used as additional identification tool when combined with other methods.

Bullet ricochets often leave impact sites that can be useful for shooting incident reconstruction. Here, we assess the proposal that these sites can potentially provide information about the design and composition of the projectile and possibly the corresponding firearm. We produced impact sites in concrete from five bullet types fired at two distances, for a total of 10 experimental conditions. Then, using elliptical Fourier analysis, we assessed the 297 bullet ricochet impact sites’ plan-view outline shapes. Of the different bullet types, the 45 calibre Hollow Points exhibited the greatest variability in ricochet impact site shape, and the greatest potential for diagnosis. Overall, statistical assessment of robust sample sizes of ricochet impact sites suggests that there is too much overlap between different bullets' ricochet sites’ plan-view form for confident identification of bullet design and composition, much less identification of the firearm from which it originated. We conclude with an extended discussion about future experiments involving bullet ricochet impact sites, including the employment of “paradigmatic classification”, which can both organise the testing of experimental variables as well as illustrate the tremendous amount of experimental work that still needs to be conducted before researchers or firearm examiners draw firm conclusions.Key PointsBullet ricochet impact sites often occur in shooting incidents.We analysed bullet richochet impact site shapes in concrete using elliptical Fourier analysis.Results suggest different bullet types’ ricochet impact shape morphospaces overlap with each other.This overlap obscures conclusions about the design and composition of the projectile and possibly the responsible firearm.

ABSTRACTThe evolution of bipedalism in the hominin lineage remains a controversial topic. The recovery of skeletal material from Aramis, the Middle Awash Project study area in Middle Awash, Afar Regional State, Ethiopia, has the potential to elucidate the transition to terrestrial bipedalism. The 4.4-million-year-old hominin Ardipithecus ramidus (ARA-VP-6/500) is represented by a relatively complete skeleton, including a complete radius. Its describers argued that it lacked features associated with suspensory behaviors, vertical climbing, and knuckle-walking. To test this hypothesis, I collected a comparative sample of radii comprising of Homo sapiens (n=27), six species of extant apes (n=96), two species of cercopithecoids (n=31), and two fossil hominins, and quantified whole bone shape using elliptical Fourier analysis (EFA). Dorsal radial morphology effectively partitions taxa by size and locomotion. The radii of knuckle-walking chimpanzees, and particularly gorillas, retain robust epiphyses and high degrees of lateral curvature, in contrast to other species. The robusticity and unique, directional curvature observed in the African ape radius may be related to knuckle-walking. The radius of ARA-VP-6/500 exhibits distinct characteristics among hominins, falling exclusively within gorilla morphospace. Although Ar. ramidus postcrania were proposed to lack features indicative of an ancestry involving knuckle-walking, vertical climbing, and suspensory behavior, this study instead contributes to growing lines of evidence suggesting that humans likely evolved from a knuckle-walking ancestor.

Species discrimination among species of Saurauia is challenging due to large morphological variation. This study examines the intraspecific variations of the 5 Philippine endemic Saurauia species using leaf size indices (LSI) and outline-based geometric morphometrics to facilitate species discrimination. Leaf samples were measured using the traditional method, scanned, converted to binary images, subjected to elliptic Fourier Analyses, and quantitatively analyzed using principal component analysis (PCA). The leaf morphology significantly differed among species based on the results of LSI and leaf shape outline analyses. The results showed 7 effective principal components (PCs), which accounted for 94.16% of the total variation. Significant differences were observed in all PCs. Discriminant analysis of the leaf shape outline confirmed the delimitation of species with scores relatively higher than the cut-off value. The tree topology from leaf shape outline, and leaf size indices all exhibited similarity in the clustering at the species level. A key to the species based on leaf morphology is also provided. Keywords: elliptic fourier analysis, kiwi, leaf size index, leaf variation, principal component analysis

A quantitative assessment of Saw Kerf floor shape patterns using outline analysis.

The present study analysed archaeological pottery in the early Yayoi period of the prehistoric Japanese archipelago, i.e. Ongagawa style pottery, which has been traditionally regarded as an indicator of the spread of rice farming in the archipelago. To this end, we quantified the two- and three-dimensional data of outlines and surfaces of the pottery, based on elliptic Fourier and spherical harmonics analyses, respectively. The results show morphological variation is spatially and temporally structured, consistent with an archaeological view that the pottery style spread via two routes (the Japan Sea route and Setouchi route) with the potential of more complex interactions between the transmission routes. The present study exemplifies a useful quantitative method to theorize cultural evolutionary trajectories of archaeological remains.

ABSTRACTA correct biological profile leads to a better understanding of the past and assists in the identification of human remains within bioarchaeology and forensic casework. Sex estimation forms a critical component of a biological profile. With the advancement of technologies such as geometric morphometrics (GMM), new methods and a deeper understanding of morphological features can be investigated digitally. However, how well do these methods compare to standard visual methods and how easy are they to employ? This research investigates the use of 2‐D shape analysis and visual morphological methods for sex estimation using the greater sciatic notch (GSN). A total of 202 adult os coxae were photographed and analyzed from the Spitalfields Coffin Plate Collection housed at the Natural History Museum, UK. Each os coxae was analyzed digitally to extract a “line” for elliptical fourier analysis (EFA) and subsequent discriminant function analysis (DFA). Os coxae were also scored using two well established morphological methods for the GSN. This study found an overall accuracy of 82.81% when using the computational method (EFA and DFA). Lower accuracies were found for the visual methods with the Bruzek method correctly classifying 82.17% and the Walker method resulting in a much lower accuracy at 72.77%. The finding of this study showcases the benefits of using more computational methods such as shape analysis/GMM. However, it has a nearly identical overall error rate to the Bruzek method and higher accuracy than the Walker method and therefore is a suitable and accurate method for sex estimation. As these practices are evolving, practitioners will have to balance the cost/benefit (e.g., time, training, and accuracy) of using the different techniques while continuing to refine and combine approaches for optimal results in biological profiling.

The El Jobo projectile points represent a distinctive design innovation of Late Pleistocene Neotropical human groups. This technology, characterized by its fusiform/lanceolate shape, has been recorded mainly in northwestern Venezuela in a variety of geographical areas and in association with megafauna killing/butchering sites. To characterize it, address its significance, and analyse possible continental relationships, four consecutive approaches were conducted. A representative sample of El Jobo projectile points was subject to technological approximation, morphological classification, outline-based geometric morphometric analysis, and elemental composition analysis. Six morphological types were recognized, for which a common series of manufacture steps was hypothesized. Mainly collateral and irregular flaking patterns were identified, also recording new basal variability, including fluting, fluting-like and reconfiguration techniques. The four most representative morphological types were subjected to morphometric analysis. Elliptic Fourier and Principal Component analyses identified at least three clusters, with width variation mainly distinguishing their shapes, and statistical tests determined significative differences between the main morphological types. The elemental analysis revealed the main use of quarzitic rocks, with variations in elemental composition indicative of diverse sources. The observed variability and cumulative evidence of El Jobo projectile points suggests their adaptation to diverse hunting strategies. The wide geographic distribution of tools and the morphometric comparison with a Monte Verde projectile suggest potential long-distance connections of El Jobo with other projectile point technologies across the continent.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12520-025-02296-2.

Coleoptera is a hyper-diverse group of animals with about 400,000 formally described species. Also the morphological diversity of beetles is very high, not only in the adults, but also in the larvae. To understand the evolutionary origin of this enormous diversity, investigations of fossils are crucial, but especially for the larvae such fossil are still scarce. In this study, we present 15 new fossil larvae from different deposits of Cretaceous to Miocene age, which we interpret as larvae of the beetle ingroup Adephaga. Most of these are three-dimensionally preserved and either embedded in amber or silicified. One specimen is a compression fossil, which is very rare for beetle larvae, and represents the first report of an adephagan beetle larva from the Early Cretaceous Jehol biota of China. Of all previously known and new fossil adephagan larvae and of selected extant ones the shapes of the head capsules and mandibles were compared with quantitative morphology methods (elliptic Fourier analysis and principal component analysis). The shapes of the fossil larvae lie all within the morphospace of those of the extant larvae, which indicates that the highest diversity in this aspect is present in the modern fauna, hence no diversity loss occurred. Other lineages of Holometabola show similar patterns, with indications of larval diversifications already in the Cretaceous, further specialisation afterwards, and no major losses. This pattern may be a reason for the enormous species richness of certain holometabloan groups in the modern fauna.

Introduction: Alongside Australopithecus africanus at Makapansgat South Africa, dated to nearly 3 million years before present, are remnants of Parapapio (Cercopithecinae). The extreme variability of this fossil assemblage has stymied efforts to specify the taxon parameters for Parapapio, which are attributed to at least three species. Study aims: The first maxillary molar occlusal outlines of the two most complete fossils attributed to Parapapio whitei are compared. The degree of group cohesion in Parapapio whitei is evaluated using three extant cercopithecoid taxa. Methods and Materials: The fossil crania from Makapangsat Members 3–4, MP 221 and MP 223, both referred to Parapapio whitei, are compared to three extant cercopithecoid taxa including Cercocebus agilis (n=8), Colobus angolensis (n=8) and Papio anubis (n=8). Molar shape is captured using elliptical Fourier analysis of occlusal outlines and molar size dimensions are estimated from measuring software. Results: MP 223 is larger than MP 221 in occlusal area and the minimum buccolingual length of M1 although the variability between the two Parapapio whitei fossils is commensurate with that observed in Papio anubis. MP 221 and MP 223 are more similar to one another in occlusal outline shape than to any other taxon. However, MP 223 falls consistently closer to Papio anubis whereas MP 221 resembles Papio anubis in some respects and Cercocebus agilis in others. Conclusion: MP 221 and MP 223 likely belong to a single species with no clear affinity to any of the extant taxa examined. The differences in molar size characterizing Parapapio whitei, a terrestrial forager, is potentially indicative of male bimaturatism or ecological variability which may also characterize Australopithecus africanus at Makapansgat.

This study was performed to assess postoperative aortic remodelling (AR) after total arch replacement for acute type A aortic dissection (AAD) with a frozen elephant trunk (FET) or conventional elephant trunk (cET). Furthermore, the shape of the residual true lumen was analysed based on elliptical Fourier analysis and evaluated as a predictor of AR. This study involved patients who underwent total arch replacement with a cET or FET for AAD from December 2006 to January 2023 at five institutions. AR was assessed at the levels of the 4th thoracic vertebra (Th4), Th7, Th10, and above the coeliac trunk. The shape of the residual true lumen at all four levels was analysed based on elliptical Fourier analysis to calculate shape patterns as principal component (PC) values. Inverse probability of treatment weighting was performed for adjustment between the groups. In total, 180 patients (88 with cET and 92 with FET) were enrolled. The complete AR rate, defined as false lumen remodelling throughout the entire descending thoracic aorta, was significantly higher in the FET than cET group (63.4% vs 32.0%, P = 0.0013). The inverse probability of treatment weighting-adjusted Fine-Gray regression model revealed that the mean PC2 (hazard ratio, 0.22; P < 0.001) and PC3 (hazard ratio, 0.24; P = 0.009) of the four levels were independent predictors of complete AR. In AAD repair, the AR rate was significantly higher with use of the FET than cET. The shape patterns of the residual true lumen can be an important reference for predicting postoperative AR.