Dimorphic Structures Research Articles

Morphometric Investigation of Sexual Dimorphism and Homotypic Variations of Ossicula Auditus in Morkaraman Sheep

In this study, it was aimed to determine the morphometric characteristics of the bones forming the ossicula auditus of Morkaraman sheep and to reveal the differences between sexes and sides. For this purpose, 24 (12 females/12 males) craniums of Morkaraman sheep were used in the study. After the craniums were macerated, the ossicula auditus in the cavum tympani were dissected out and morphometric data were determined by taking linear measurements. Sexually dimorphic structures and homotypic variations of the obtained morphometric data were statistically calculated. It was observed that the bones forming the ossicula auditis were malleus, incus and stapes, respectively, When the morphometric data obtained were analyzed, it was determined that there were statistically dimorphic differences between sexes in the parameters of LH, WHM and LhM (P

Structure and sexual dimorphism of the first antennae in Penaeus vannamei, Boone, 1931

ABSTRACT This contribution is a histological and scanning electron microscopy study of major flagellar setae of antennules from the most cultured crustacean species, Penaeus vannamei. Antennule samples were collected from females and males of selected species and processed for histological as well as scanning electron microscopy (SEM) evaluation. The histological and SEM description of major setae from antennules, namely aesthetascs, plumose setae, and male spines are presented in detail. A unique sexually dimorphic structure, male spines on the inner (medial) flagella, is reported for the first time in a penaeid shrimp. These spines are robust structures, short and thick with non-permeable cuticle and no terminal pore, innervated by receptor neuron clusters. This histological organization suggests the spines are sensilla for mechanoreception, possibly involved in courtship mechanoreception, complementing chemosensory information from aesthetascs. Additionally, SEM observations of other antennule setae are presented, including asymmetric setae associated with aesthetascs.

Midface Skeletal Sexual Dimorphism: Lessons Learned from Advanced Three-dimensional Imaging in the White Population.

Facial shape is significantly influenced by the underlying facial bony skeleton. Sexual dimorphisms in these structures are crucial for craniofacial, aesthetic, and gender-affirming surgery. Previous studies have examined the orbits and upper face, but less is known about the midface. This study aimed to elucidate the sexual dimorphism in the midface region, focusing on the maxilla and zygomatic bones. A retrospective review was conducted using facial computed tomography scans from 101 White patients aged 20-79 years, using Materialise Mimics and 3-Matics for segmentation and 3D reconstruction. Measurements and statistical shape modeling of the midfacial skeleton were performed. Our results show a distinct sexual dimorphism in the midfacial skeletal structure across all age groups. Women typically had a narrower bizygomatic width by 1.5 mm (P = 0.04), a shallower maxillary depth by 1.6 mm (P < 0.01), and a midfacial vertical height that was 4 mm shorter than that of men (P = 0.018). In contrast, men exhibited a greater distance between the frontozygomatic sutures by 5.4 mm (P < 0.01), a 3-mm greater interorbitale distance (P < 0.01), and a 2.1-mm wider infraorbital foramina distance (P = 0.007). There were no significant differences in the pyriform and maxillary angles (P = 0.15 and P = 0.52, respectively). Our analysis of midfacial skeletal anatomy revealed sexual dimorphism differences. Men exhibited more pronounced facial features than women, with a broader horizontal midfacial skeleton, a longer midfacial vertical height, and greater maxillary depths compared with women.

Two new species of Caribbiantes, with the redescription of the type species and a review of male genital patterns in Antillean Stenostygninae (Opiliones: Laniatores: Biantidae)

Caribbiantes cubanus Šilhavý, 1973, type species of genus Caribbiantes Šilhavý, 1973, is redescribed based on abundant material from the type locality, providing new data on its morphological variability and penis morphology. Two new species of Caribbiantes are described, C. obtusus sp. nov. and C. barbai sp. nov., based on additional specimens from central and eastern Cuba, for which we give information on their geographical distribution, intraspecific variability and habitat. A new diagnosis for Caribbiantes and updated geographic distributions of the included species are provided. The sexually dimorphic glandular structures on the metatarsus III of males for all Caribbiantes species are described. Male dimorphism, most evident in the robustness of the chelicerae, is reported for the studied species. The male genitalia patterns of Antillean stenostygnines species are described. The phylogenetic affinity of Antillean stenostygnines with Stenostygnus Simon, 1879, a genus from the north of South America, is discussed based on some morphological traits.

The effects of the industrial transition on lower limb bone structure: A comparison of the inhabitants of Pecos Pueblo and present-day Indigenous peoples of New Mexico.

Comparisons between Indigenous peoples over time and within a particular geographic region can shed light on the impact of environmental transitions on the skeleton, including relative bone strength, sexual dimorphism, and age-related changes. Here we compare long bone structural properties of the inhabitants of the late prehistoric-early historic Pecos Pueblo with those of present-day Indigenous individuals from New Mexico. Femora and tibiae of 126 adults from Pecos Pueblo and 226 present-day adults were included in the study. Cross-sectional diaphyseal properties-areas and second moments of area-were obtained from past studies of the Pecos Pueblo skeletal sample, and from computed tomography scans of recently deceased individuals in the present-day sample. Femora and tibiae from Pecos individuals are stronger relative to body size than those of present-day Indigenous individuals. Present-day individuals are taller but not wider, and this body shape difference affects cross-sectional shape, more strongly proximally. The tibia shows anteroposterior strengthening among Pecos individuals, especially among males. Sexual dimorphism in midshaft bone shape is stronger within the Pecos Pueblo sample. With aging, Pecos individuals show more medullary expansion but also more subperiosteal expansion than present-day individuals, maintaining bone strength despite cortical thinning. Higher activity levels, carried out over rough terrain and throughout adult life, likely explain the relatively stronger lower limb bones of the Pecos individuals, as well as their greater subperiosteal expansion with aging. Greater sexual dimorphism in bone structure among Pecos individuals potentially reflects greater gender-based differences in behavioral patterns.

Effect of Heat Treatment on Fatigue Properties of TA15 Titanium Alloy Repaired by Laser Deposition

Laser‐deposition repair technology is employed to repair damaged TA15 titanium alloy forgings. Heat treatment is used to control the microstructure, strength, and plasticity of these repaired forgings. The fatigue properties and crack initiation and propagation characteristics of the repaired parts are studied. Optical microscopy and electron microscopy are used to analyze the microstructure, fatigue fracture, and longitudinal section near initiation. In the results, it is indicated that the tensile and fatigue properties of repaired parts after 900 °C heat treatment are superior to those treated at other temperatures. This is attributed to the strong tissue sensitivity of the repaired specimens’ performance. With increasing heat‐treatment temperature, the secondary α phase in the dimorphic structure tissue thickens. Additionally, the restoration zone develops in layered α phases and becomes truncated, leading to shortening and thickening. The heat‐affected zone undergoes a transformation from a transitional structure to a basket organization. After heat treatment at 1000 °C, the microstructure becomes relatively slender, cracks propagate readily, and the resistance is weakened.

Sex Differences in Brain Disorders.

A remarkable feature of the brain is its sexual dimorphism. Sexual dimorphism in brain structure and function is associated with clinical implications documented previously in healthy individuals but also in those who suffer from various brain disorders. Sex-based differences concerning some features such as the risk, prevalence, age of onset, and symptomatology have been confirmed in a range of neurological and neuropsychiatric diseases. The mechanisms responsible for the establishment of sex-based differences between men and women are not fully understood. The present paper provides up-to-date data on sex-related dissimilarities observed in brain disorders and highlights the most relevant features that differ between males and females. The topic is very important as the recognition of disparities between the sexes might allow for the identification of therapeutic targets and pharmacological approaches for intractable neurological and neuropsychiatric disorders.

Orbital shape in sheep and goats with sex and breed factors.

The purpose of this study was to identify the dimorphic structures of the orbita based on breed and sex factors through shape analysis across species. Additionally, the study aimed to ascertain the variability between the two species. A total of 86 (51 sheep-Akkaraman [Ak] and Morkaraman [Mk], 35 goats-Hair [Hr] and Honamlı [Hm]) skulls were used in the study. It was decided to designate 36 landmarks to represent the orbit's edge. In the principal component analysis, 68 PCs were calculated. It was determined that PC1, PC2 and PC3 explained the total variance in morphology by 26.909%, 16.147% and 13.616%, respectively. According to the cross-validation results, the goats were grouped with 95% (Hm: 100%, Hr: 90%), while the sheep were grouped with 56% (Ak: 50%, Mk: 63%). Therefore, dimorphism among goat breeds on orbita shape was more pronounced compared to sheep. In the discriminant function analysis of the sex groups, Procrustes and Mahalanobis distance values in goats were 0.04425425 (p < 0.0001) and 5.3733 (p = 0.9550), in sheep 0.03513424 (p < 0.0001) and 7.1003 (p = 0.9414), respectively, was detected. According to the cross-validation results, in terms of sex, goats were correctly grouped at a rate of 74% (F: 73%; M: 75%) and sheep breeds were correctly grouped at a rate of 72% (F: 77%; M: 66%). Factors such as habitat selection, breeding behaviours and ecological environment may show anatomical differences within breeds as well as between breeds. Therefore, various measurement techniques are used to reveal these differences. As a result, it is thought that the study will contribute to many disciplines, especially taxonomy and zooarchaeology, by analysing the shape of the orbita of sheep and goat breeds, the domestication of which dates back to ancient times, and revealing the similarities and differences between species and according to sex.

Geometric Morphometric Analysis of the Condylus Occipitalis and Foramen Magnum in Sheep and Goat

Aim: The aim of this study was to reveal the dimorphic structures of the foramen magnum and condyle occipitalis through an interspecies shape analysis and to determine the variability between sheep and goats. Materials and Methods: The study includes data from 81 skulls (46 sheep and 35 goat) for this aim. The foramen magnum frame shape and the condyle occipitalis variation were determined using type I (anatomical) and type III (semilandmarks). Results: Accordingly, was determined 30.76, 14.94 and 14.07 of the total shape variation of PC1, PC2 and PC3, respectively. It was determined that condylus occipitalis was primarily responsible for the shape variation according to PC1, and foramen magnum was responsible for the secondarly. It was found to explain the shape variation of the right condyle occipitalis to a great extent compared with PC2, while in PC3, it caused the entire right condyle occipitalis to explain the shape variation of the extreme lateral corner of the left condyle occipitalis and the left edge of the foramen magnum. The discriminant function analysis determined the Procrustes and Mahalanobis distances to be 0.12293879 (p &lt; 0.0001) and 67.7482 (p &lt; 0.0044), respectively. Conclusion: As a result, the geometric morphometry method is regarded to be a useful tool for detecting changes in skull shape between species and can thus be used successfully for taxonomic, archaeological, and forensic research.

Distinct developmental mechanisms influence sexual dimorphisms in the milkweed bug Oncopeltus fasciatus.

Sexual dimorphism is common in animals. The most complete model of sex determination comes from Drosophila melanogaster, where the relative dosage of autosomes and X chromosomes leads indirectly to sex-specific transcripts of doublesex (dsx). Female Dsx interacts with a mediator complex protein encoded by intersex (ix) to activate female development. In males, the transcription factor encoded by fruitless (fru) promotes male-specific behaviour. The genetics of sex determination have been examined in a small number of other insects, yet several questions remain about the plesiomorphic state. Is dsx required for female and male development? Is fru conserved in male behaviour or morphology? Are other components such as ix functionally conserved? To address these questions, we report expression and functional tests of dsx, ix and fru in the hemipteran Oncopeltus fasciatus, characterizing three sexual dimorphisms. dsx prevents ix phenotypes in all sexes and dimorphic traits in the milkweed bug. ix and fru are expressed across the body, in females and males. fru and ix also affect the genitalia of both sexes, but have effects limited to different dimorphic structures in different sexes. These results reveal roles for ix and fru distinct from other insects, and demonstrate distinct development mechanisms in different sexually dimorphic structures.

Sexually dimorphic characters of the ultimate legs in lithobiid centipedes (Myriapoda, Chilopoda, Lithobiomorpha): morphology and implications for reproductive behaviour.

Many species of lithobiomorph centipedes present a pronounced sexual dimorphism reflected in remarkable structural modifications on the ultimate legs of males. Most records of these male secondary sexual characters addressed taxonomy, helping to identify and characterize species or diagnose genera, but information on their diversity, detailed morphology and possible function(s) is scarce. In this study, nine species of the two lithobiid genera Lithobius Leach, 1814 and Eupolybothrus Verhoeff, 1907 were investigated, using light and scanning electron microscopy to document the detailed morphology of secondary sexual characters of male ultimate legs. Secondary sexual characters affecting the cuticle of the ultimate legs are described in detail and found to often be associated with sensilla, interpreted here as chemo- and mechanoreceptors, and with clusters of pores, a hitherto undescribed pore-distribution for this group. The tibial nodule of the species Lithobius nodulipes Latzel, 1880, was additionally examined with histological semi-thin sections. These results revealed that the clustered pores are connected to glandular tissue, and are, based on their morphology, interpreted as openings of flexo-canal epidermal glands. The presence of various sensory and glandular structures associated with sexual dimorphism indicates a likely role during courtship and mating. The closely related species examined in this research show comparable dimorphic structures, which are otherwise species-specific. Morphological observations on secondary sexual structures inform on reproductive biology in groups like lithobiomorphs for which there are limited behavioural data. This article is protected by copyright. All rights reserved.

Homo mobilis: Some observations on the characteristics of the Kura-Araxes cultural complex

The terms ‘enclosed nomadism’ and ‘dimorphic structure’ which are used to describe the relationship between the Near Eastern mobile pastoralists living in the same habitat and sedentary agricultural communities, are fully applicable also for the description of the socio-cultural landscape of the second half of the 4th millennium BC in Armenia. Archaeological data accumulated year by year provide an opportunity to consider in more detail the relationship between the agricultural and specialized mobile pastoral groups in the region. From this point of view, important data are provided by the settlement of Godedzor, which represents the final stage of the Chalcolithic period, as well as by the clusters with materials of the early stage of the Kura-Araxes cultural complex (Talin, Avan, Tsaghkalanj), which are not associated with settlements.

The functional morphology of species-specific male structures and lack of female coevolution in Lytta (Adicolytta) eucera (Chevrolat 1834) (Coleoptera Meloidae)

Possible functions of several species-specific, sexually dimorphic male structures and of the male genitalia of Lytta eucera were deduced from observations of behaviour in the field and captivity, and were used to test theories of sexual selection. The male rubbed and tapped on the female’s antennae with sexually dimorphic segments of his antennae, and on her elytra with brushes of setae on his hind tarsi. He forcefully grasped the female’s prothorax and at least occasionally perforated the female’s prothoracic membranes with his modified middle tibiae, and her relatively uniform, membranous vaginal lining with his strong aedeagal teeth. His aedeagal teeth snagged her vaginal lining, and his gonostyli usually pressed against a featureless external female intersegmental membrane. None of these male structures was used as a weapon or in threat displays. No female structure fitted tightly in a “lock-and-key” manner with any of the male structures, nor was any female structure capable of selectively impeding their use, thus ruling out some hypotheses explaining their species-specificity in males. Female resistance to males, including occasional violent “tantrum” displays, was energetic, persistent, and highly effective; the functional significance of this resistance is unclear. If females distinguish the stimuli produced by species-specific traits of male genitalia, as supposed by some hypotheses, they likely use higher-level analyses in the central nervous system rather than the locations of the particular sense organs that are stimulated.

Cellular-scale sex differences in extracellular matrix remodeling by valvular interstitial cells.

Males acquire calcific aortic valve disease (CAVD) twice as often as females, yet stenotic valves from females display significantly higher levels of fibrosis compared to males with similar extent of disease. Fibrosis occurs as an imbalance between theproduction and degradation of the extracellular matrix (ECM), specifically type I collagen. This work characterizes ECM production and remodeling by male and female valvular interstitial cells (VICs) to better understand the fibrocalcific divergence between sexes evident in CAVD. Male and female VICs were assessed for gene and protein expression of myofibroblastic markers, ECM components, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs (TIMPs) via qRT-PCR and western blot. Overall metabolic activity was also measured. Activity assays for collagenase and gelatinase were performed to examine degradation behavior. Male VICs produced greater levels of myofibroblastic markers while female VICs showed greater metabolic activity and collagen production. In general, females displayed a greater level of MMP expression and production than males, but no sex differences were observed in TIMP production. Male VICs also displayed a greater level of collagenase and gelatinase activity than female VICs. This work displays sex differences in ECM remodeling by VICs that could be related to the sexual dimorphism in ECM structure seen in clinical CAVD.

Sexual Dimorphism in the Extracellular and Pericellular Matrix of Articular Cartilage

ObjectiveWomen have a higher prevalence and burden of joint injuries and pathologies involving articular cartilage than men. Although knee injuries affecting young women are on the rise, most studies related to sexual dimorphism target postmenopausal women. We hypothesize that sexual dimorphism in cartilage structure and mechanics is present before menopause, which can contribute to sex disparities in cartilage pathologies.DesignBovine knee was used as a model to study healthy adult cartilage. We compared elastic moduli under compression, abundances of extracellular and pericellular matrix (PCM) proteins using proteomics, and PCM constituency with tissue immunofluorescence. The gene expression of matrix-related genes under basal, anabolic, and catabolic conditions was assessed by quantitative polymerase chain reaction (qPCR).ResultsThe equilibrium modulus was higher in male cartilage compared with female cartilage. Proteoglycans were not associated with this biomechanical dimorphism. Proteomic and pathway analyses of tissue showed dimorphic enriched pathways in extracellular matrix (ECM)-related proteins in which male cartilage was enriched in matrix interconnectors and crosslinkers that strengthen the ECM network. Moreover, male and female tissue differed in enriched PCM components. Females had more abundance of collagen type VI and decorin, suggesting different PCM mechanics. Furthermore, the activation of regenerative and catabolic function in chondrocytes triggered sex-dependent signatures in gene expression, indicating dimorphic genetic regulation that is dependent on stimulation.ConclusionsWe provide evidence for sexual dimorphism in cartilage before menopause. Some differences are intrinsic to chondrocytes’ gene expression defined by their XX versus XY chromosomal constituency.

P48. Sex Differences in Cortical Thickness in Cannabis Use Disorder

Sex differences exist in cannabis use characteristics and its neurobiological effects, but little is known of cannabis-related sexual dimorphism in brain structure. We investigated sex differences in cortical and subcortical gray matter volumes among adults with Cannabis Use Disorder (CUD) and examined whether these differences related to behavior.

Estrogen Receptor-A in Medial Preoptic Area Contributes to Sex Difference of Mice in Response to Sevoflurane Anesthesia

A growing number of studies have identified sex differences in response to general anesthesia; however, the underlying neural mechanisms are unclear. The medial preoptic area (MPA), an important sexually dimorphic structure and a critical hub for regulating consciousness transition, is enriched with estrogen receptor alpha (ERα), particularly in neuronal clusters that participate in regulating sleep. We found that male mice were more sensitive to sevoflurane. Pharmacological inhibition of ERα in the MPA abolished the sex differences in sevoflurane anesthesia, in particular by extending the induction time and facilitating emergence in males but not in females. Suppression of ERα in vitro inhibited GABAergic and glutamatergic neurons of the MPA in males but not in females. Furthermore, ERα knockdown in GABAergic neurons of the male MPA was sufficient to eliminate sex differences during sevoflurane anesthesia. Collectively, MPA ERα positively regulates the activity of MPA GABAergic neurons in males but not in females, which contributes to the sex difference of mice in sevoflurane anesthesia.

Exploring sexual dimorphism of human occipital and temporal bones through geometric morphometrics in an identified Western‐European sample

AbstractSex estimation is a paramount step of bioprofiling in both forensic anthropology and osteoarchaeology. When the pelvis is not optimally preserved, anthropologists commonly rely on the cranium to accurately estimate sex. Over the last decades, the geometric morphometric (GM) approach has been used to determine sexual dimorphism of the crania, in size and shape, overcoming some difficulties of traditional visual and metric methods. This article aims to investigate sexual dimorphism of the occipital and temporal region through GM analysis in a metapopulation of 50 Western‐European identified individuals. Statistical analyses were performed to compare centroid size and shape data between sexes through the examination of distinct functional modules. Regression and Procrustes ANOVA were used to examine allometric and asymmetrical implications. Discriminant functions, combining size and shape data, were established. Significant dimorphism in size was found, with males having larger crania, confirming the major influence size has on cranial morphology. Allometric relationships were found to be statistically significant in both right and left temporal bones while shape differences between sexes were only significant on the right temporal bone. The visualization of the mean consensus demonstrated that males displayed a larger mastoid process associated with a reduced mastoid triangle and less projected occipital condyles. This exploratory study confirms that GM analysis represents an effective way to quantitatively capture shape of dimorphic structures, even on complex rounded ones such as the mastoid region. Further examination in a larger sample would be valuable to design objective visualization tools that can improve morphoscopic sex estimation methods.

An exploration of sacral morphology using geometric morphometrics and three-dimensionally derived interlandmark distances.

Accurate sex estimation is an important component of a biological profile in forensic anthropology. The pelvis is widely accepted as the most dimorphic osseous structure, and thus, this dimorphism is also reflected by the sacrum. This study aimed to explore sacral morphology and to derive a practically applicable discriminant function formula for sex estimation. A total of 20 three-dimensional landmarks were digitised on a sample of 200 sacra from a sample of South Africans of African descent (Black South Africans) with ages ranging between 20 and 90years, equally distributed for sex. Geometric morphometric methods were used to analyse sacral morphology and sexual dimorphism as it captures size-independent shape variation and three-dimensional morphology. Size-independent shape analysis revealed four sacral structures and metrics that account for most of its shape variation. When these were compared between the sexes, we found that sacral curvature pattern, rather than depth, differed between sexes and that males have greater anterior sacral heights. Females have larger alae relative to the body of S1. In addition, the anterior posterior breadth of the sacral canal is larger in males, as is the relative size and projection of the superior articular processes. Discriminant analyses of these data produced average accuracies of only 72.5%, but this improved to 84.5% when using novel interlandmark distances derived from the raw coordinate data. Our results demonstrate that landmark-based techniques allow for a more nuanced understanding of structural variation. In addition, accuracies were achieved that surpass traditional metrics using an equal number of variables. These results contribute to our understanding of sacral dimorphism and will assist in forensic casework.

Digest: Recurrence of sexually dimorphic neurological structure in neotropical butterflies.

Although many traits can be gained or lost over evolutionary time, it has long been unclear whether complex sensory processing structures, such as brain neuropils, can be regained after having been lost. Morris etal. show that a part of the brain once lost in butterflies, a macro-glomeruli complex (MGC) in the antennal lobe, is prevalent and has diversified in the Ithomiini tribe. This structure is sexually dimorphic in some species. This re-emergence of a complex sensory processing structure is likely driven by ecological factors.