Anatomical Record最新文献

{"title":"Growth patterns of theoretical bite force and jaw musculature in southern sea otters (Enhydra lutris nereis).","authors":"Chris J Law","doi":"10.1002/ar.25665","DOIUrl":"https://doi.org/10.1002/ar.25665","url":null,"abstract":"<p><p>The transition from milk to solid food requires drastic changes in the morphology of the feeding apparatus and its performance. As durophagous mammals, southern sea otters exhibit significant ontogenetic changes in cranial and mandibular morphology to presumably enable them to feed on a variety of hard-shelled invertebrate prey. Juvenile sea otters begin feeding independently by 6-8 months of age, but how quickly they reach sufficient maturity in biting performance remains unknown. Here, I found that the theoretical bite force of southern sea otters does not reach full maturation until during the adult stage at 3.6 and 5.0 years of age in females and males, respectively. The slow maturation of biting performance can be directly attributed to the slow growth and development of the cranium and the primary jaw adductor muscle (i.e., the temporalis) and may ultimately impact the survival of newly weaned juveniles by limiting their ability to process certain hard-shelled prey. Alternative foraging behaviors such as tool use, however, may mitigate the disadvantages of delayed maturation of biting performance. In analyses of sexual dimorphism, I found that female otters reached bite force maturation earlier, whereas male otters exhibit initial rapid growth in bite force-to quickly reach sufficient biting performance needed to process prey early in life-followed by a slower growth phase toward bite force maturation that coincides with sexual maturity. This biphasic growth in bite force suggests that male-to-male competition for resources and mates exhibits strong selection in the growth and development of skull form and function in male otters. Overall, this study demonstrates how the analysis of anatomical data can provide insight on the foraging ecologies and life histories of sea otters across ontogeny.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144025027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variation in parrot jaw musculature.","authors":"Ana Carolina L Faillace, Arin Berger, Marcelo Ismar S Santana, Adam Hartstone-Rose","doi":"10.1002/ar.25667","DOIUrl":"https://doi.org/10.1002/ar.25667","url":null,"abstract":"<p><p>Psittaciformes, the order encompassing parrots and their relatives, are highly diverse and generally known for having a strong beaks used for multiple behaviors. The muscles related to the masticatory apparatus should reflect this functional complexity; however, few studies have described the cranial myology across the order. Through original dissections, we describe and compare the masticatory musculoskeleton of 27 species-the most taxonomically diverse sample of psittaciformes to date. As in previous studies, we found osteological differences in the configuration of the suborbital arch, zygomatic process, and temporal fossa, and while most muscles are relatively similar across the order, there are notable exceptions found in the morphology of the m. pseudomasseter, m. adductor mandibulae externus, pars rostralis, and a venter externus portion of the m. pterygoideus ventralis, pars lateralis. Our findings reinforce the amazing anatomical diversity found within this group-data that can be incorporated into future studies of the biomechanics and diversification of this order. Further analysis should focus on (a) filling in more of the remarkable number of species across the order, especially uncommon and functionally interesting taxa unavailable in the present study, (b) examining dietary specialization to understand whether dietary adaptive signals are encoded within this anatomy, and (c) advancing to anatomical studies with other techniques such as DiceCT to visualize the relationship and biomechanics of these muscles in 3D space and be able to evaluate specimens relatively non-destructively, a priority for hard-to-dissect (e.g., small) taxa and (e.g., rare) specimens that collections wish to more fully preserve.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143796987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modularity and integration of the neural arch and vertebral centrum in primates.","authors":"Catalina I Villamil, Emily R Middleton","doi":"10.1002/ar.25653","DOIUrl":"10.1002/ar.25653","url":null,"abstract":"<p><p>The vertebral column consists of multiple homologous elements that have specialized within and between taxa and serve important functions in positional support and as protection for the central nervous system. The study of modularity and integration provides new insights into the evolution of complex structures such as the vertebral column. Patterns of modularity and integration may reflect underlying genetic-developmental patterns and facilitate evolution. Previous studies have identified mixed modularity patterns within and between elements across mammals generally, within primates and carnivorans. Here, we assess modularity within and between elements in the complete post-axial vertebral column in four catarrhine taxa: Macaca (n = 96), Hylobates (n = 77), Pan (n = 92), and Homo (n = 151). We use the Covariance Ratio (CR) to estimate r² and the standardized eigenvalues (SVE) variance for comparative purposes. Our results show that there is general, widespread integration within the catarrhine vertebral column, both within and between elements. Hominoids tend to display greater modularity than do macaques, but these estimates are rarely significant. Clusters of modularity in the mid-cervical and upper thoracic regions may relate to special nervous system structures in these areas, and locomotor behaviors in general may influence patterns of modularity in primates. In particular, we find that size is a pervasive factor affecting integration among vertebral elements, though its effects on specific structures are variable. Our results generally do not agree with those found across mammals or within carnivorans, and future studies should focus on genus-level assessments across a variety of taxa.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143626757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-resolution 7-Tesla magnetic resonance imaging and post-processing for 3-dimensional reconstruction of the membranous labyrinth in healthy adults.","authors":"Joon Soo Kim, Zahra N Sayyid, Diane Jung, Syed Ameen Ahmad, Jintong Li, Adrian Paez, Yinghao Li, Francis Deng, John P Carey, Jun Hua, Bryan K Ward","doi":"10.1002/ar.25647","DOIUrl":"10.1002/ar.25647","url":null,"abstract":"<p><p>The membranous labyrinth of the inner ear is a complex network of endolymph-filled structures critical for auditory and vestibular function. Pathological distension of these spaces, termed endolymphatic hydrops (EH), is associated with disorders such as Ménière's disease (MD). However, diagnosing inner ear pathologies remains challenging due to limitations in traditional imaging techniques, which lack the spatial resolution required to assess these intricate structures. Advances in 7-Tesla (7T) magnetic resonance imaging (MRI) now allow for high-resolution visualization of the inner ear. In this study, we used 7T T2-weighted and delayed post-contrast 3D-FLAIR sequences to improve visualization of the membranous labyrinth. As the inner ear region is particularly challenging for MRI due to severe transmit (B₁) field inhomogeneity, dielectric pads and radiofrequency (RF) shimming were used to optimize the sequences. Subtracted images were processed using 3D segmentation techniques to isolate endolymphatic compartments, enabling the first in vivo 3D reconstructions using 7T MRI and volumetric analyses of the utricle, semicircular canal ducts, saccule, and cochlear duct. The total mean endolymphatic volume in five healthy adult participants was 192.62 mm³ ± 36.83 mm³. These imaging techniques provide a quantitative framework for assessing EH and comparing normal versus diseased inner ear anatomy. Our findings demonstrate the potential of 7T MRI to enhance the diagnosis and understanding of inner ear disorders, particularly MD.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12355385/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143606790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A perspective from the Mesozoic: Evolutionary changes of the mammalian skull and their influence on feeding efficiency and high-frequency hearing.","authors":"Julia A Schultz","doi":"10.1002/ar.25652","DOIUrl":"https://doi.org/10.1002/ar.25652","url":null,"abstract":"<p><p>The complex evolutionary history behind modern mammalian chewing performance and hearing function is a result of several changes in the entire skeletomuscular system of the skull and lower jaw. Lately, exciting multifunctional 3D analytical methods and kinematic simulations of feeding functions in both modern and fossil mammals and their cynodont relatives approach this topic, giving fresh insights into the history of mammalian masticatory behaviors and their evolutionary trends. One crucial transformation in this context is the segregation of postdentary bones (becoming the mammalian middle ear) from the lower jaw, which is posited to have led to the important functional decoupling of the hearing and feeding systems. Evolution of the middle ear is regarded as the key transition that enhanced both mammalian chewing performance and hearing capacity. Three major functional parts undergo substantial evolutionary changes in this process that are anatomically linked to each other: the lower jaw and dentition, middle ear, and inner ear. Sound, transmitted via vibrations of the bony middle ear elements to the inner ear, is converted into movements of the endolymph fluid that shift hair cells of the organ of Corti, triggering neural stimuli perceived as hearing. Structural changes in one part of the system influence the function of the other two. In this review, I highlight recent advances in research focusing on the enhancement of both chewing performance and hearing ability in mammalian history to feature the mechanisms that led to the decoupling of the hearing system (i.e., middle and inner ear) from the feeding system.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143606383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Helmeted hornbill cranial kinesis: Balancing mobility and stability in a high-impact joint.","authors":"Mike Schindler, Benjamin Flaum, Armita Razieh Manafzadeh, Viktoriia Kamska, Kanmani Chandra Rajan, Maria Jose Robles Malagamba, Ruien Hu, Daniel Baum, Mason N Dean","doi":"10.1002/ar.25613","DOIUrl":"https://doi.org/10.1002/ar.25613","url":null,"abstract":"<p><p>Prokinesis-in which a craniofacial joint allows the rostrum to move relative to the braincase-is thought to confer diverse advantages in birds, mostly for feeding. A craniofacial joint would, however, be a weak link if cranial stability is important. Paradoxically, we have identified a craniofacial joint in helmeted hornbills (Rhinoplax vigil), birds known for violent head-butting behavior. To understand how the helmeted hornbill balances the competing demands of kinesis and collision, we combine manual craniofacial joint manipulation, skull micro-computed tomography (μCT) and articular raycasting, also comparing our data with μCT scans of 10 closely-related species that do not aggressively head-butt. The helmeted hornbill boasts a particularly massive casque, a distinctive upper mandible protrusion fronting the braincase; the craniofacial joint is immediately caudal to this, a standard prokinetic hinge joint position, at the dorsal border of braincase and upper mandible. However, whereas the craniofacial joint in all bucerotiform bird species we examined was only a slender bridge, the helmeted hornbill's joint is exceptionally reinforced. Raycasting analyses revealed high correspondence between the extremely broad joint facets, with reciprocal topographies of braincase and casque fitting like complex puzzle pieces. The result is a joint with a single degree of freedom and limited range of motion, increasing the gape when elevated, but conversely stable when depressed. With the dense network of bony trabeculae in the casque also funneling back to this joint, we infer that the damaging effects of high cranial impact are mitigated, not by dissipating impact energy, but through a skull architecture with a prodigious safety factor.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early life functional transitions impact craniofacial morphology in osteogenesis imperfecta.","authors":"Courtney A Miller, Tanusha Emanuel, Rachel A Menegaz","doi":"10.1002/ar.25640","DOIUrl":"https://doi.org/10.1002/ar.25640","url":null,"abstract":"<p><p>Early life behaviors have a profound role in shaping adult craniofacial morphology. During early life, all mammals undergo the dynamic transition from suckling to mastication, a period coinciding with rapid cranial biomineralization. Osteogenesis imperfecta (OI), a genetic disorder that impacts the production of type I collagen, disrupts biomineralization, leading to craniofacial growth differences affecting quality of life. This study investigates craniofacial development during infant oral motor developmental stages in OI mice compared to unaffected wild-type littermates (WT mice). We hypothesize OI mice will exhibit smaller overall size, and the adult OI phenotype will develop postnatally in response to masticatory loading. Point cloud and fixed landmarks were collected from micro-computed tomography scans, then geometric morphometric analyses and interlandmark distances (ILDs) compared craniofacial size and shape between OI and WT mice at birth (P0; n = 27 OI murine/20 WT) and postnatal Days 7 (P7; n = 21/21), 14 (P14; n = 16/20), 21 (P21; n = 20/26), and 28 (P28; n = 26/33). This study found no size and shape differences between genotypes at birth. Starting at P7, OI mice are significantly (p < 0.05) smaller and display pronounced shape changes (p < 0.001) characterized by a larger neurocranium and a shorter viscerocranium. At P21, significant differences emerge in cranial base orientation, neurocranial width, viscerocranial shortening, and zygomatic arch displacement. These findings underscore the importance of early life oral motor stages in developing the adult OI craniofacial phenotype and oral health, suggesting earlier craniofacial interventions may improve effective treatment of OI.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143484584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology and function of pinniped necks: The long and short of it.","authors":"Justin Keller, Annalisa Berta, Mark Juhn, Blaire Van Valkenburgh","doi":"10.1002/ar.25642","DOIUrl":"https://doi.org/10.1002/ar.25642","url":null,"abstract":"<p><p>Terrestrial vertebrates from at least 30 distinct lineages in both extinct and extant clades have returned to aquatic environments. With these transitions came numerous morphological adaptations to accommodate life in water. Relatively little attention has been paid to the cervical region when tracking this transition. In fully aquatic cetaceans, the cervical vertebrae are compressed, largely because a loss of neck mobility reduces drag. We ask whether this pattern of cervical evolution is present in the more recently evolved semiaquatic pinnipeds. Here, we compare neck morphology and function in three families of pinnipeds, the Otariidae, Phocidae, and Odobenidae as well as between pinnipeds and their terrestrial arctoid relatives (ursids and mustelids). Using cranial CT scans, we quantified the occipital surface area for neck muscle attachment as well as vertebral size and shape using linear measurements. Results show that pinnipeds have a relatively larger occipital surface area than ursids and terrestrial mustelids, suggesting that marine carnivorans have enlarged their neck muscles to assist with head stabilization during swimming. Within pinnipeds, we found quantitative differences in cervical morphology between otariids and phocids that coincide with their locomotor style. Phocids are hindlimb-dominated swimmers that propel themselves with pelvic oscillations. Their necks are relatively stiff and their cervical vertebrae are compressed anteroposteriorly with reduced muscular attachment areas. By contrast, otariids are forelimb-dominated swimmers that locomote in water and on land using their pectoral limbs, often recruiting their neck to initiate turns underwater as well as assisting in \"walking\" on land. Consequently, otariids have stronger, more flexible necks than phocids, which is reflected in more elongate cervical vertebral centra with larger muscle attachments. The walrus (Odobenidae) has a cervical vertebrae morphology intermediate to that of phocids and otariids, consistent with a phocid swimming mode combined with a more muscular neck that likely functions in intraspecific conflict and haul-out behavior.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143469964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review of the anatomical basis for predicting plutonium alpha particle radiation induced osteogenic cancers.","authors":"Scott C Miller","doi":"10.1002/ar.25641","DOIUrl":"10.1002/ar.25641","url":null,"abstract":"<p><p>Plutonium was discovered and first synthesized in the early 1940's. Several isotopes of plutonium are used in nuclear technologies, ²³⁸Pu for heat generation and ²³⁹Pu for energy production and weapons. Both isotopes emit alpha particles, which pose a significant radiation hazard when incorporated into the body. Alpha particles emitted during ²³⁹Pu decay deposit energy along a very short path in biological tissues (≈45 μm in soft tissues). Thus, defining the anatomical locations of these deposits is essential to identify the cells at risk of radiation damage and potential malignant transformation. Bone is a primary site for plutonium deposition and retention. Plutonium exposures are associated with increases in osteogenic cancers. Plutonium is preferentially deposited on endosteal and endocortical bone surfaces, particularly those surrounded by red versus yellow bone marrow. Red marrow is more vascularized with a sinusoid network, while yellow marrow is largely a closed capillary system. Cancellous bone in red marrow sites has greater bone turnover rates and relatively more plutonium-related bone cancers than in yellow marrow sites. The relationships of plutonium deposits in bone and potential alpha particle exposures to cells that include osteoclasts, reversal cells, canopy cells, osteoblasts, bone lining cells, and osteogenic progenitors of the basic multicellular unit during bone modeling and remodeling are reviewed. Differences in distributions of ²³⁹Pu versus naturally occurring tumors in humans and experimental animals are noted. This review emphasizes the importance of the anatomical locations of plutonium deposition and retention in the skeleton and the potential relative radiation risks from alpha particles to bone cells and their progenitors.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12353174/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143442685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Human interparietal bones: Examination of existing classification schemes and development of a graphic library depicting variations.","authors":"Melissa D Clarkson, Rhian R Dunn, Joseph T Hefner, Holly A Long, Micayla C Spiros","doi":"10.1002/ar.25643","DOIUrl":"10.1002/ar.25643","url":null,"abstract":"<p><p>Due to its complex ossification during development, the superior region of the human occipital bone is a frequent site of supernumerary bones known as interparietal bones. Interparietal bones have been extensively studied across various disciplines, resulting in multiple classification schemes using icon-like graphics to represent categories of interparietal variants. However, disparities across these classification schemes reveal the need for a standardized system to facilitate comparisons and permit data pooling across studies. Based on an extensive literature review and the examination of physical specimens, a graphic library of 80 evidence-based graphics capturing interparietal variants was designed for community use. It provides five graphics of different morphologies of the lambdoid suture, 64 graphics of interparietal bones, six of ossicles at lambda, three of mendosal suture variants, and two of intrasutural ossicles. This approach allows additional graphics to be added in the future as needed. Graphics are compared to those from existing classification schemes and an exercise using the graphics to classify crania was performed. In the broadest sense, this research establishes a model for improved practices in representing and sharing morphological data.</p>","PeriodicalId":50793,"journal":{"name":"Anatomical Record","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12350755/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143426598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}