Homologous Landmarks Research Articles

Gender prediction using geometric morphometry with parameters of the cranium obtained from computed tomography images

Purpose: The gender difference of the cranium skeleton is of great importance in forensic anthropology and forensic medicine sciences. This study is based on this hypothesis and the gender prediction rate was obtained by processing cranium images obtained from computed tomography (CT) using geometric morphometry. Materials and Methods: CT images of 200 individuals between the ages of 25 and 65 were used in our study. The images were opened at the personal workstation Horos Medical Image Viewer (Version 3.0, USA) program and processed with 3D Curved Multiplanar Reconstruction (MPR). The line passing through the nasion and inion points of the images obtained as a result of the process was determined, and all images were brought to the orthogonal plane. Later, the images were overlapped and saved in JPEG format with 100% magnification. JPEG images saved were converted into TPS format, and 21 homologous landmarks were placed. Generalized Procrustes Analysis (GPA) and Principal Component Analysis (PCA) were applied to the coordinates of landmarks, and shape variations and dimensionality were corrected by gathering the images to the center of gravity. Next, Linear Discriminant Analysis (LDA) was applied to the coordinates, the dimensionality of which was corrected. Results: The study found that 74.465% of the coordinates of 21 homologous landmarks gathered to the center of gravity could be explained with the first three PCs. As a result of the LDA applied to these coordinates, a gender prediction rate of 86.5% was obtained. In addition, a slight difference was found between the GPA sum of squares and the tangent sum of squares (0.57). Conclusion: The images of the cranium obtained from CT showed a high dimorphism by geometric morphometry analysis.

Phenotypic divergence of Glossina morsitans (Diptera: Glossinidae) populations in Zambia: Application of landmark-based wing geometric morphometrics to discriminate population-level variation.

An important consequence of the discontinuous distribution of insect populations within their geographic range is phenotypic divergence. Detection of this divergence can be challenging when it occurs through subtle shifts in morphological traits with complex geometries, such as insect wing venation. Here, we used landmark-based wing geometric morphometrics to investigate the population-level phenotypic variation of the two subspecies of Glossina morsitans, G. m. centralis Machado and G. m. morsitans Westwood that occur in Zambia. Twelve homologous landmarks digitised on the right wings of 720 specimens collected from four and five sites (80 per site with 1:1 sex ratio) within the G. m. centralis and G. m. morsitans range respectively, were subjected to generalised Procrustes analysis to obtain wing centroid size (CS) and wing shape variables. Linear permutation models and redundancy analysis were then used to compare CS and wing shape between male and female G. morsitans, the two subspecies G. m. centralis and G. m. morsitans, the sexes of each subspecies and between sample locations within each subspecies range, respectively. Significant differences in CS and wing shape were observed between G. morsitans sexes, subspecies and sample locations within each subspecies range. A neighbour-joining cladogram derived from the analysis of Procrustes distances showed that tsetse within each subspecies range were highly divergent. We conclude that G. morsitans populations in Zambia exhibit significant population-level variation in fly size and wing shape which suggests high levels of population structuring. The main drivers of this structuring could be random genetic drift in G. m. centralis demes and local adaptation to environmental conditions in G. m. morsitans populations. We therefore recommend molecular studies to estimate the levels of gene flow between these populations and identify possible barriers to genetic flow.

Investigation of the shape of goat (capra hircus) astragalus via geometric morphometry method

The aim of this study is to determine the effect of sex on shape of goat astragalus via geometric morphometry method. A total of 37 astragalus bone samples collected from 16 female and 21 male goats were used as material. Bone samples were cleaned from skin and soft tissue and then macerated by boiling. Astragalus bone samples were photographed from a distance of 20 cm dorsally by focusing on the center of the bone. The photographs were transferred to the computer in JPEG format. Principal Component Analysis, Regression Analysis, Canonical Variate Analysis, and Discriminant Function Analysis were conducted using the Cartesian coordinate values, which were obtained by homologous landmark marking. The first two principal components accounted for 75.967% of the total shape variation. Shape variation was determined in different regions of the astragalus. According to the scatter plot of male and female individuals, male individuals were completely placed within the confidence interval ellipse of female individuals. It was found that allometric effect on the shape of astragalus bone was not statistically significant. As a result of Canonical Variate Analysis, mahalanobis and procrustes distances were detected as 2.9216 (p

Sella turcica and facial bones: Morphological integration in the human fetal cranium.

The cranial base plays a significant role in facial growth, and closer analyses of the morphological relationship between these two regions are needed to understand the morphogenesis of the face. Here, we aimed to study morphological integration between the sella turcica (ST) and facial bones during the fetal period using geometric morphometrics. Magnetic resonance images of 47 human fetuses in the Kyoto Collection, with crown-rump lengths of 29.8-225 mm, were included in this study. Anatomical homologous landmarks and semilandmarks were registered on the facial bones and the midsagittal contour of the ST, respectively. The shape variations in the craniofacial skeleton and the ST were statistically investigated by reducing dimensionality using principal component analysis (PCA). Subsequently, the morphological integration between the facial bones and ST was investigated using two-block partial least squares (2B-PLS) analysis. PCA showed that small specimens represented the concave facial profile, including the mandibular protrusion and maxillary retrusion. The 2B-PLS showed a strong integration (RV coefficient = 0.523, r = .79, p < .01) between the facial bones and ST. The curvature of the anterior wall of the ST was highly associated with immature facial morphology characterized by a concave profile. The strong integration between the two regions suggested that the anterior ST may be associated with facial morphology. This result quantitatively confirms previous studies reporting ST deformities in facial anomalies and induces further research using postnatal subjects.

Geometric morphometric analysis of new zealand rabbit cranium

This study, aimed to determine the shape features of the New Zealand rabbit skull and to reveal the differences between individuals and genders in terms of shape features. For this purpose, the geometric morphometry method was used. A total of 10 female and 10 male New Zealand Rabbit craniums were used. The skulls were photographed in a dorsal, ventral and lateral view, and the mandible was photographed in a lateral view. Homologous landmarks were marked on the photographs. Consensus graphs were created by the TpsRelw (Version 1.70) program. Additionally, principal component analysis and relative warp analysis were performed. As a result of the study, principal components explained 34.813%, 57.225% and 42.427% of the total shape difference in the dorsal, ventral and lateral views of the skull, respectively. In the first principal component graph obtained as a result of principal component analysis, no significant clustering was observed between genders. According to the graphics obtained in the MorphoJ program, inter-individual variation was detected mainly in the viscerocranium, followed by the neurocranium. This study will contribute to morphological and archaeological studies on rabbit skulls.

Morphological variation of Oreochromis niloticus (Lacépède, 1803) populations in stressed environment: Middle stream of Comoé River (Ivory Coast)

This work aims to assess the influence of environmental stress in the middle course of the Comoé River on the morphological characteristics of Oreochromis niloticus populations using the geometric morphometric approach. A total of 248 specimens of O. niloticus were collected from four sites (M'Basso, YèrèYèrè, Abradinou and Bettié). No specimen of O. niloticus has been collected from the Manzan River, which has a high level of gold panning activity. Nineteen (19) homologous landmarks were digitized on each individual. Data were studied using principal component analysis, canonical variable analysis, discriminant function analysis and allometric analysis. The PC1 and PC2 axes show an extension of the deformation grids at the level of the head and the caudal and dorsal fins. However, the PC3 axis almost exhibits a deformation grid that deforms at the caudal fin, pectoral fin, and dorsal fin. The results of the various analyzes showed significant differences between the morphology of the populations studied. These differences were observed mainly in the head, dorsal and pectoral fins. The disturbance of aquatic habitats has an impact on the morphology of specimens of O. niloticus from the middle course of the Comoé River. A slight deformation is recorded in the individuals of O. niloticus at M'Basso, considered the least disturbed site. On the other hand, a strong deformation is observed in specimens from the YèrèYèrè, Abradinou and Bettié sites which are more disturbed.

Geometric Morphometrics Applied to Cartography

The morphological differences between two geographical maps can be highlighted by a polycentric distance cartogram resulting from a bidimensional regression. Beyond the communicational interest of the transformations thus produced, the method makes it possible to reveal the differences in structure and therefore constitutes a real research tool. However, bidimensional regression can only compare the shape of two maps. Since the 1990s, geometric morphometrics has revolutionized the morphological analysis of natural structures (and others). It has since been applied in many fields of research but not in cartography. This article describes the theoretical and methodological bases of a method combining bidimensional regression with a geometric morphometrics approach to compare the shape of several geographical maps. Geometric morphometrics and bidimensional regression indeed share common approaches of the statistical shape analysis like homologous landmarks and interpolation grids. However, there is no software in geometric morphometrics capable of directly reading geographical data, which would facilitate the work of cartographers accustomed to GIS software. That is why we present MapMorphy, a tool specifically developed for this task. An example on ancient maps illustrates the method.

Assessment of Morphometric Variations Among the Populations of Asian Sheat Catfish &lt;i&gt;Wallago attu&lt;/i&gt; (Siluridae) from Five Indian Rivers

Morphological variations of the Asian sheat catfish, Wallago attu (Bloch and Schneider, 1801) sampled from the rivers Gomti, Ganga, Yamuna at Lucknow, Kanpur and Agra districts in Northern India, river Hooghly at Kolkata in Eastern India and river Pampa at Kerala in Southern India were analyzed in the present study. Images of 261 specimens of W. attu were taken without harming the fish to evaluate the morphometric variation using 8 digitized homologous landmarks for truss analysis and geometric morphometrics. Size corrected morphometric variables were analyzed using analysis of variance (ANOVA), multivariate analysis of variance (MANOVA), principal component analysis (PCA) and discriminant function analysis (DFA). Coefficients of all PCs were positively and negatively correlated to 31 significant (p 0.001) truss measurements due to variations in size and shape. Morphometric measurements lying in the head region such as head length (HL), eye diameter (ED), inter-orbital length (IOL) and snout length (SNL) contributed most to differentiate the populations in truss analysis. The ED, HL, SNL and IOL of Yamuna fish was significantly (p 0.001) smaller than the other fish populations. This could be attributed to the heavy pollution load in the Yamuna River and differences in the feeding regimes of fish. PCs and relative warps depicted differences in geometric analysis because of body shape variations among different river populations. The scatter plot in DFA revealed the presence of three distant and different phenotypic groups of W. attu among five wild river populations of fish with 70.5 and 83.9% of correct classification of fish into their original groups in truss and geometric analysis respectively. A single homogenous stock of fish was found to be in the rivers Gomti, Ganga and Hooghly because of a high level of intermixing (maximum misclassification) among the three river populations, whereas Yamuna and Pampa populations were two non-overlapping isolated groups due to negligible intermixing. These variations in the present study might be the effect of geographical isolation and river fragmentation due to the change in habitat that restricts fish movements. This is the first report on the morphometric assessment of W. attu that provides base line data for further confirmatory stock studies that would be useful for conservation and sustainable management of this vulnerable fish.

Ontogenetic skull variation in a shovel-headed amphisbaenian species.

Leposternon microcephalum is a species belonging to the Amphisbaenia, a group of burrowing reptiles. Amphisbaenia present various morphological and physiological adaptations that allow them to penetrate the ground and live underground, through a system of galleries and permanent chambers that they build themselves. Among the morphological adaptations in this group, those of the skull stand out as it serves as the main excavation tool. Four basic skull shapes are recognized: rounded, keeled, shovel-shaped, and spade-shaped. The skull of L. microcephalum belongs to this last type, which is considered the most specialized. The species inhabits soils that are highly compacted and difficult to penetrate. Among the species of Leposternon present in South America, L. microcephalum has the widest distribution, being found in all Brazilian biomes and neighboring countries such as Bolivia, Argentina, Paraguay, and Uruguay. The analysis of the skull of this species was carried out using three-dimensional geometric morphometrics (3D-GMM), a technique that allows comparative analysis, through robust statistical methods, of shape and its variations, using Cartesian coordinate data from a configuration of homologous landmarks. The technique allows the size and shape components of a structure to be analyzed separately. From an ontogenetic point of view, this methodology had also been used to investigate variations in Cynisca leucura, a member of the Amphisbaenidae with a rounded head. Our hypothesis is that the patterns of morphological differentiation in the skull, mainly in the intermediate and occipital regions, are similar in different Amphisbaenia species. Therefore, the objective of this study was to analyze cranial morphological variations in an ontogenetic series of L. microcephalum using 3D-GMM. Computed Tomographic scans of 13 specimens were analyzed: juveniles (N = 8) and adults (N = 5), based on 20 landmarks that characterize the skull. Principal components and regression analyses between shape (dependent variable) and size (independent variable) showed a clear difference between the cranial morphological pattern of juvenile individuals and that of adults. For instance, young specimens tend to have a dorsoventrally tall neurocranium, with the tip of the snout more anteriorly oriented and its dorsal border subtly curved. Dorsally, the parietal region is thicker and smoothly dome-shaped in juveniles. As in C. leucura, the variation was strongly correlated with the size change from juvenile to adult, indicating a dominant role for ontogenetic allometry in determining skull shape.

Comparison of traditional and geometric morphometrics using Lake Huron ciscoes of the Coregonus artedi complex

AbstractObjectiveHere we determine how traditional morphometrics (TM) compares with geometric morphometrics (GM) in discriminating among morphologies of four forms of ciscoes of the Coregonus artedi complex collected from Lake Huron.MethodsOne of the forms comprised two groups of the same deepwater cisco separated by capture depth, whereas the other three forms were shallow‐water ciscoes.ResultOur three groups of shallow‐water ciscoes were better separated (3% vs. 19% overlap) in principle component analysis (PCA) with TM data than with GM data incorporating semilandmarks (evenly spaced nonhomologous landmarks used to bridge between widely separated homologous landmarks). Our two deepwater cisco groups, comprising a putatively single form collected from different depths, separated more in PCAs with GM data (33% overlap) than in PCAs with TM data (66% overlap), an anomaly caused by greater decompression of the swim bladder and deformation of the body wall in the group captured at greater depths. Separation of the two deepwater cisco groups captured at different depths was not affected by the removal of semilandmarks. Assignment of forms using canonical variate analysis accurately assigned 86% of individuals using TM data, 98% of individuals using GM data incorporating semilandmarks, and 100% of individuals using GM data without semilandmarks. However, we considered assignments from the same form of deepwater cisco into separate groups as misassignments resulting from different capture depths, which reduced the accuracy of assignments with GM data incorporating semilandmarks to 66%.ConclusionOur study implies that TM will continue to have an important role in morphological discrimination within Coregonus and other fishes similarly shaped.

Geometric Morphometric Analysis of Skull in Honamli, Hair, Kilis and Saanen Goat Using Dorsal Landmarks

The aim of the study was to analyze the dorsal aspect of the skulls of Honamli, Hair, Kilis and Saanen goats by geometric morphometric method. A total of 48 adult goat skulls, 6 male and 6 female, were used for each breed. After the skulls were photographed dorsally, 10 homologous landmarks were marked. As a result of our study, the degree of dorsal separation of the skulls according to sex was found to be limited. Nevertheless, significant separation was seen in the Honamli skulls of females and in the Honamli and Saanen skulls of males. This information may serve as a reference for the skull remains of ruminants.

Comparative Morphometric Analysis of the Azov Anchovy (&lt;i&gt;Engraulis encrasicolus maeoticus&lt;/i&gt; Pusanov, 1926) and the Black Sea Anchovy (&lt;i&gt;E. encrasicolus ponticus&lt;/i&gt; Alexandrov, 1927) Based on the Body Shape

A comparative analysis of body shape was performed on 841 specimens of anchovy collected from 21 catches from the Sea of Azov, the Kerch Strait, and the Black Sea off the Crimea and the northeastern coast of the Caucasus in 2006–2007 and 2016–2017. Twenty-three measurements between 12 homologous landmarks of the body of each specimen according to the “Truss Network System” served as characters for analysis. Fifteen characters showed significant differences between the Azov anchovy Engraulis encrasicolus maeoticus Pusa-nov, 1926 and the Black Sea anchovy E. encrasicolus ponticus Alexandrov, 1927. Specimens of the Azov subspecies had larger relative values for all characters of the head region, the height of the trunk region, the re-lative length of the bases of the dorsal and anal fins, and the height of the base of the caudal fin. Specimens of the Black Sea subspecies had a greater postdorsal length and a larger distance from the end of the dorsal fin base to the end of the anal fin base. A multivariate principal component analysis revealed the highest variabi-lity of characters of body height, which depends on the fatness of the fish and demonstrates seasonal dyna-mics. The second group combines characters that do not have a seasonal component (dimensions of the head region, lengths of the bases of the dorsal and anal fins, and postdorsal distance) and can be used for distinguishing the shape of the Azov and Black Sea anchovies. The success rate of classification of Azov and Black Sea anchovies according to the body shape measurement characters using the discriminant analysis was 83.4%.

Baculum shape complexity correlates to metrics of post-copulatory sexual selection in Musteloidea.

The penis bone, or baculum, is present in many orders of mammals, although its function is still relatively unknown, mainly due to the challenges with studying the baculum in vivo. Suggested functions include increasing vaginal friction, prolonging intromissionand inducing ovulation. Since it is difficult to study baculum function directly, functional morphology can give important insights. Shape complexity techniques, in particular, are likely to offer a useful metric of baculum morphology, especially since finding homologous landmarks on such a structure is challenging. This study focuses on measuring baculum shape complexity in the Musteloidea-a large superfamily spanning a range of body sizes with well-developed, qualitatively diverse bacula. We compared two shape complexity metrics-alpha shapes and ariaDNE and conducted analyses over a range of six different coefficients, or bandwidths, in 32 species of Musteloidea. Overall, we found that shape complexity, especially at the baculum distal tip, is associated with intromission duration using both metrics. These complexities can include hooks, bifurcationsand other additional projections. In addition, alpha shapes complexity was also associated with relative testes mass. These results suggest that post-copulatory mechanisms of sexual selection are probably driving the evolution of more complex-shaped bacula tips in Musteloidea and are likely to be especially involved in increasing intromission duration during copulation.

A Comparison of Semilandmarking Approaches in the Visualisation of Shape Differences.

In landmark-based analyses of size and shape variation and covariation among biological structures, regions lacking clearly identifiable homologous landmarks are commonly described by semilandmarks. Different algorithms may be used to apply semilandmarks, but little is known about the consequences of analytical results. Here, we assess how different approaches and semilandmarking densities affect the estimates and visualisations of mean and allometrically scaled surfaces. The performance of three landmark-driven semilandmarking approaches is assessed using two different surface mesh datasets with different degrees of variation and complexity: adult human head and ape cranial surfaces. Surfaces fitted to estimates of the mean and allometrically scaled landmark and semilandmark configurations arising from geometric morphometric analyses of these datasets are compared between semilandmarking approaches and different densities, as well as with those from warping to landmarks alone. We find that estimates of surface mesh shape (i.e., after re-semilandmarking and then re-warping) made with varying numbers of semilandmarks are generally consistent, while the warping of surfaces using landmarks alone yields surfaces that can be quite different to those based on semilandmarks, depending on landmark coverage and choice of template surface for warping. The extent to which these differences are important depends on the particular study context and aims.

Geometric Morphometric Investigation of Incus in Horse (Equus ferus caballus) and Donkey (Equus Asinus)

In this study, it was aimed to determine the shape of the incus in horse and donkey by geometric morphometric method and to evaluate the shape differences between horse’s and donkey’s incus. The left incus bone of 5 adult horses and 5 donkeys were used in the study. Incus were photographed at same lateral direction. Thirteen homologous landmarks were marked from the photographs using TpsUtil (Version 1.79) and TpsDig2 (Version 2.31) software. As a result of the study, the first principal component explained 38,642% of the total shape variation. In the PC1 plot, samples were clearly clustered by group. Acording to canonical varians analysis, in the wire frame warp graphic, the corpus incudis edges (right, left, and bottom) were flatter in donkeys. Angle at the LM13 level was more pronounced on the crus breve. The apex of the crus longum (Landmark 4, 5, and 6) was wider in donkey. In the study, the morphological features of horse’s and donkey’s incus were determined by geometric morphometric method. This study is important in that it is the first geometric morphometric study on the incus that is one of the ossicula auditus in horse and donkey. We think that the study will contribute to the anatomy of the ossicula auditus in the equide family.

Classifying organisms and artefacts by their outline shapes

We often wish to classify objects by their shapes. Indeed, the study of shapes is an important part of many scientific fields, such as evolutionary biology, structural biology, image processing and archaeology. However, mathematical shape spaces are rather complicated and nonlinear. The most widely used methods of shape analysis, geometric morphometrics, treat the shapes as sets of points. Diffeomorphic methods consider the underlying curve rather than points, but have rarely been applied to real-world problems. Using a machine classifier, we tested the ability of several of these methods to describe and classify the shapes of a variety of organic and man-made objects. We find that one method, based on square-root velocity functions (SRVFs), outperforms all others, including a standard geometric morphometric method (eigenshapes), and that it is also superior to human experts using shape alone. When the SRVF approach is constrained to take account of homologous landmarks it can accurately classify objects of very different shapes. The SRVF method identifies a shortest path between shapes, and we show that this can be used to estimate the shapes of intermediate steps in evolutionary series. Diffeomorphic shape analysis methods, we conclude, now provide practical and effective solutions to many shape description and classification problems in the natural and human sciences.

Skull of the Asian (Paradoxurus Hermaphroditus) and the golden (Paradoxurus Zeylonensis) palm civet: Geometric morphometric analysis using palate, tooth and frontal landmarks.

This study aims to determine the differences in skull between Asian and golden palm civets by geometric morphometric method. The landmarks were marked on these photographs, and principal component, classical cluster and canonical variance analyses were performed. The method of geometric morphometry of the skull is a powerful tool used to differentiate the species. Fourteen and 20 homologous landmarks were marked using tpsutil and tpsdig2 programs on the frontal and palatinal directional photographs, respectively. As a result of the study, the first principal component (PC1) accounted for 33.586% on the frontal view, 41.602% on the palatinal view of the total shape differences, respectively. Distinctive differences on the frontal and palatinal view were observed in the caudal, rostrolateral and the last molars and the caudal palatine, respectively.

Visualizing Variability in Ceramic Micro-Curvature though Novel 3D Morphometric Mapping and Sliced Segmental Extraction

In recent years, two-dimensional (2D) outline-based morphometric analysis has begun to be the standard means of shape analysis in the study of ceramics. Despite the ever-increasing repertoire of three-dimensional (3D) ceramic data available to researchers, due to challenges in utilizing landmark-based geometric morphometrics on ceramics, many contemporary studies are forced to rely on 2D outlines, which account for only a small degree of shape variance. Consequently, notions of intra-vessel variance cannot be thoroughly extrapolated, and as such, important themes such as morphogenesis during the production process have not been thoroughly examined. By contrast, the present project utilizes a method derived from high-resolution 3D scans combining “morphometric mapping” and “sliced segmental extraction” to visualize previously unrecognized variability in the micro-curvature of full vessels. This method does not require homologous landmarks, but rather, employs a multistage approach that allows for several stages of analysis that can be adjusted to each given research project, and thus has the potential to elucidate idiosyncratic variability during the morphogenesis process. <strong>概要</strong> 近年、土器研究において、2次元の輪郭を用いた形状（形態）解析が主流となりつつある。土器の3次元データのレパートリーは増え続けているが、ランドマークを用い た幾何学的形態計測法を土器に適用することは困難であるため、多くの研究は形態のばらつきが小さい2次元外形図に頼らざるを得ない。そのため、製品内のばらつきの概念を十分に定義できず、製作過程における形態形成などの重要なテーマについては十分に検討されていない。これに対し、本研究では、高解像度3Dスキャンから得られる「形態計測マッピング法」と「セグメント抽出法」を組み合わせ、これまで認識されていなかった土器全体の表面の微小曲線のばらつきを可視化することに成功した。この手法は、相同ランドマークを必要とせず、研究プロジェクトごとに分析の様々な段階において調整可能な分析手法を採用しているため、形態形成過程における特異様式を明らかにできる可能性がある。 <strong>キーワード:</strong> 三次元分析; 土器; 日本考古 学; 形態計測マッピング法; セグメント抽出法

Geometric Morphometric Analysis on the skull of the Red Fox (Vulpes Vulpes)

This study was carried out to determine the shape of the fox skull by the geometric morphometric method according to gender. For this purpose, four female and nine male fox skulls were used. The skulls were photographed from the dorsal and lateral aspects. Eleven homologous landmarks on the dorsal aspect and 19 homologous landmarks on the lateral aspect were marked on the photographs of the skull. Principal component analysis and Relative warp analysis were performed on the coordinate values of the images. In addition, MorphoJ software was used to determine the shape differences and directions of the landmarks. According to principal component analysis, male and female individuals were mainly concentrated to the y axis’s right on lateral images, and female and male individuals were not concentrated in one region on dorsal images. Therefore, according to the principal component analysis, no significant gender difference was found. The consensus graph determined that the oral edge of the incisive tooth and the cranial edge of the canine tooth in females were ventrally directed compared to males. It is thought that the findings obtained as a result of the study will contribute to zooarchaeological and taxonomic research.

Differential Impact of Forest Fragmentation on Fluctuating Asymmetry in South Amazonian Small Mammals

(1) Background: Southern Amazonia encompasses some of the most human-impacted and deforested regions of South America, resulting in a hyper-fragmented landscape. In this context, by using a geometric morphometrics approach, we aimed to examine the effect of forest fragmentation on developmental instability (DI) of the mandible, assessed by variation of fluctuating asymmetry (FA), in four neotropical small mammal species inhabiting the municipality of Alta Floresta (Brazil). (2) Methods: The impact of fragment area, fragment shape, isolation, and edge length on DI were assessed by measuring variation in mandibular FA in the long-tailed spiny rat (Proechimys longicaudatus), the hairy-tailed bolo mouse (Necromys lasiurus), the woolly mouse opossum (Marmosa demerarae), and the Amazonian red-sided opossum (Monodelphis glirina). Mandibles from a total of 304 specimens originating from different-sized fragments (ranging from 5 to 900 ha) were used. Twelve homologous landmarks were digitized in photographs of the mesial view of each hemi-mandible. (3) Results: The two largest species, P. longicaudatus and M. demerarae, exhibited significantly higher levels of FA in mandibular shape in small fragments (5–26 ha) in comparison to large ones (189–900 ha). Edge length negatively impacted M. demerarae, the only arboreal species, reinforcing its strongest dependence on core forest habitats. (4) Conclusions: For small mammal communities, we propose that fragments &gt;~200 ha should be the focus of conservation efforts, as both resilient and more sensitive species would benefit from their more preserved biotic and abiotic conditions. Conversely, fragments &lt;~25 ha seem to lead to a significant increase in stress during developmental stages.