Journal of Morphology最新文献

{"title":"Solvent Dehydration and Low Temperature Vacuum Drying for SEM Imaging of Pre-Hatching Frog Embryos","authors":"Daniela Zurita-Paredes,&nbsp;Daniela Flores-Bolaños,&nbsp;Karla Vizuete,&nbsp;Alexis Debut,&nbsp;Andrés Romero-Carvajal","doi":"10.1002/jmor.70030","DOIUrl":"https://doi.org/10.1002/jmor.70030","url":null,"abstract":"<div>\u0000 \u0000 <p>Scanning electron microscopy (SEM) is a fundamental technique to study the morphology of anuran embryos and tadpoles. Here, we present a drying method for SEM imaging of late frog embryos using commonly available dehydration solvents such as ethanol or methanol, xylene, and applying low temperature vacuum freeze drying. Briefly, embryos from early embryonic gills development to hatching were fixed with a paraformaldehyde—glutaraldehyde mix, then dehydrated to ethanol or methanol, and then slowly dried using low temperature and constant vacuum pressure. An extra step of clearing using xylene after ethanol dehydration improved results considerably. Our protocol successfully preserved embryo shape and the morphology of fragile and delicate superficial structures (e.g., external embryonic gills, apical ectodermal microridges and surface ciliation), while avoiding the use of some SEM toxic reagents.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362728","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":"Anatomy of the Critically-Endangered Anji Salamander (Hynobius amjiensis) Provides New Insights Into Morphological Evolution of Salamanders","authors":"Cang-Song Chen,&nbsp;Jia Jia,&nbsp;Xian-Ting Wang,&nbsp;Jia Yang,&nbsp;Ke-Qin Gao","doi":"10.1002/jmor.70028","DOIUrl":"10.1002/jmor.70028","url":null,"abstract":"<div>\u0000 \u0000 <p>The Anji Salamander (<i>Hynobius amjiensis</i>) is a critically-endangered amphibian endemic to the Tianmushan Mountain area in southeastern China. As most of its congeneric species in the ancestral salamander family Hynobiidae, the osteology of <i>H</i>. <i>amjiensis</i> has remained essentially unknown and has hampered efforts in understanding morphological evolutionary patterns of early salamanders. Here, we investigate the skeletal anatomy of <i>H</i>. <i>amjiensis</i> based on microcomputed tomography scans of post-metamorphosed juvenile and adult specimens. Our results reveal Hynobiidae has more early-tetrapod-like plesiomorphic characters than expected, as <i>H</i>. <i>amjiensis</i> has a stapedial foramen in the middle ear and two centralia and a centrale-radius contact in the limb. We demonstrate that <i>Hynobius amjiensis</i> is the first known living salamander species with a stapedial foramen whose absence was believed to unite salamanders and anurans, and hence opens major questions on the evolution of the middle ear in modern amphibians: if some salamanders and caecilians had a stapedial foramen inherited from their common ancestor, when and how many times was the foramen lost independently in modern amphibians, and how did this structural loss impact the phylogenetic evolution of salamander clades? Our findings of hyper-ossified pectoral and pelvic girdles and loss of postminimus in the pes in <i>H</i>. <i>amjiensis</i> demonstrate that functional morphological features in hynobiids are potentially informative in phylogeny and ontogeny of early salamanders.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143066135","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":"Morphological Criteria for Staging Near-Hatching Embryos of the Domesticated Mallard (Anas platyrhynchos) and Swan Goose (Anser cygnoides)","authors":"Bassel Arnaout,&nbsp;Kaylen Brzezinski,&nbsp;Benjamin Steventon,&nbsp;Daniel J. Field","doi":"10.1002/jmor.70027","DOIUrl":"10.1002/jmor.70027","url":null,"abstract":"<p>Studying avian embryology necessitates reliable and precise staging tables—descriptions of embryonic features appearing during development that are used to approximate the extent of embryonic development from fertilisation to hatching. Staging tables for waterfowl (Anseriformes) have previously been established based on morphological features from fertilisation to approximately 10 days before hatching. Embryonic changes over the final 10 days of pre-hatching development have also been documented and proposed as useful staging criteria. However, the reliability of these changes—which focus on the size of the bill and middle toes—as useful staging criteria across different waterfowl breeds has not been fully examined. To evaluate the reliability of these criteria for staging near-hatching embryos, we examined 27 embryos of Mallard (<i>Anas platyrhynchos</i>) and Swan Goose (<i>Anser cygnoides</i>). Comparisons with previously published data revealed that size variation within the same developmental stage across breeds is equivalent to within-breed variation across different stages, suggesting limited reliability of bill and middle toe size for staging waterfowl embryos. Consequently, we devised novel staging criteria for waterfowl based on four easily measurable morphological traits and show that these criteria allow correct stage identification with over 70% accuracy. Our results highlight the importance of quantifying staging accuracy for improving the reliability of embryonic staging tables.</p>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11780221/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143066136","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":"Functional Morphology of Hatching: Ontogeny and Distribution of Hatching Gland Cells in Red-Eyed Treefrogs and a New Marker for Anuran Hatching Enzyme","authors":"María José Salazar-Nicholls,&nbsp;Henry Macías Bazante,&nbsp;Karen M. Warkentin","doi":"10.1002/jmor.70029","DOIUrl":"10.1002/jmor.70029","url":null,"abstract":"<div>\u0000 \u0000 <p>Environmentally cued hatching (ECH) is widespread in animals and requires regulation of hatching mechanisms. Enzymatic digestion of the egg membrane is a common hatching mechanism in vertebrates and invertebrates. In amphibians and fishes, hatching enzymes (HE) are synthesized and released by hatching gland cells (HGC), whose functional ontogeny determines when hatching can occur. Ontogenetic studies of HGC development or HE expression are limited, based largely on external cell morphology; few markers for HGC or HE are available, and those appear specific for <i>Xenopus</i>. Moreover, mechanisms regulating HE release are unknown in anurans. To investigate variation in the hatching process, we need tools to identify and analyze its components. <i>Agalychnis callidryas</i> (Hylidae) is a well-established model of ECH, showing plastically timed, acute HE release, unlike the gradual release described for some aquatic anurans. We developed a new antibody marker for <i>A. callidryas</i> HE that also labels HGC/HE in glassfrogs (Centrolenidae). As glassfrogs and treefrogs diverged 62 mya, the antibody may be broadly useful in anurans. We used the AcHE antibody to examine the development and distribution of HGC and accumulation of HE, two key elements of hatching mechanisms, in <i>A. callidryas</i>. We found a much larger number (ca. 4200) and broader distribution of HGC than has been documented in any amphibian, with HGC densely but non-contiguously distributed over the front of the head and eyes and scattered along the dorsal midline. HE expression begins before hatching competence and is strong throughout the plastic hatching period, unlike HE gene expression which diminishes after competence. The distribution and expression ontogeny of <i>A. callidryas'</i> HE/HGC appear related to their hatching performance, plasticity, and embryo morphology. The AcHE antibody will enable comparative research to elucidate co-variation in the functional morphology, performance, and ecological context of hatching.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143059349","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":"Ecomorphology of South American Penguins","authors":"Elliott Bloom,&nbsp;Juan Carlos Torres-Mura,&nbsp;Marcelo Bertellotti,&nbsp;Fritz Hertel","doi":"10.1002/jmor.70025","DOIUrl":"10.1002/jmor.70025","url":null,"abstract":"<div>\u0000 \u0000 <p>A major goal of evolutionary ecology is to understand the interaction between ecological differences and the functional morphology of organisms. Studies of this type are common among flying birds but less so in penguins. Penguins (Spheniscidae) are the most derived extant underwater flying birds using their wings for swimming and beak when foraging. The Humboldt Penguin (<i>Spheniscus humboldti</i>) and Magellanic Penguin (<i>S. magellanicus</i>) occur along the coast of South America and their morphology was compared in allopatry and sympatry throughout their ranges. Measurements included: mass, tarsus length, four beak/head dimensions, bite force, wing loading, and aspect ratio. A thin-plate spline/relative warp analysis was also used to detect subtle differences in wing shape. Both species generally overlapped in trait morphology, but Magellanic Penguins showed greater trait diversity. Wing morphology was more homogenous between species than beak morphology indicating a similar mode of locomotion but potential differences in prey procurement. Morphological character displacement in sympatry was only evident in beak length. Local adaptation was common in other traits, and Punta Norte (Argentina) was often distinct in having high variation, notably in beak depth, wing loading, and wing shape (relative warp 1). This may be attributed to the fact that penguins here dive deep and forage farther from their colony; they also have a greater colony size that may contribute to greater intraspecific competition for resources. These results support a potentially optimal wing design for aquatic movement, which likely applies to other penguin species. Differences in morphology may also be related to differences between Atlantic and Pacific ecosystems.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007041","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":"Heads and Tails: Comparative Osteology of Nearctic Dipsadid Snakes","authors":"Roberta Azeredo Murta-Fonseca,&nbsp;Daniel Silva Fernandes,&nbsp;Angele Martins","doi":"10.1002/jmor.70019","DOIUrl":"10.1002/jmor.70019","url":null,"abstract":"<div>\u0000 \u0000 <p>Although numerous studies have addressed some aspects of the cranial osteology of Nearctic dipsadid species, only the species within the genera <i>Heterodon</i> and <i>Carphophis</i> have a formal published description of their skull. Similarly, vertebral data on such species are extremely scarce, and most of the available literature is focused on fossils. Such group has a complex phylogenetic history, being recovered as monophyletic or nonmonophyletic depending on the approach. In this paper, we provide detailed and comparative descriptions of the osteology of dipsadid species distributed in the Nearctic region based on 69 specimens of dry material and high-resolution computed tomography (CT) scans. Additionally, we explore the morphological variation of the skull and cervical vertebrae within the context of distinct phylogenetic hypotheses previously proposed. Only two suprageneric groups previously proposed shared exclusive morphological traits: (<i>Carphophis amoenus</i> + <i>Contia tenuis</i>), proposed by three studies, and (<i>Diadophis punctatus (Ca. amoenus</i> + <i>Co. tenuis</i>)), proposed by one study. Large and detailed studies on the skull, mandible, and vertebrae represent an important step toward the understanding of the evolution of species, especially when they also show intraspecific variation.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143007042","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":"Dental Anomalies and Cranio-Dental Ontogeny in a Captive Wild Boar Population From France","authors":"Helder Gomes Rodrigues,&nbsp;Clémence Le Gouellec,&nbsp;Katia Ortiz,&nbsp;Yann Locatelli,&nbsp;Dimitri Neaux,&nbsp;Thomas Cucchi","doi":"10.1002/jmor.70024","DOIUrl":"10.1002/jmor.70024","url":null,"abstract":"<div>\u0000 \u0000 <p>Dental anomalies are frequent in boars and pigs, and they generally affect the first premolar loci. The prevalence of these dental anomalies was investigated in a large number of populations around the world. These studies mainly focused on the influence of domestication, size, sexual dimorphism or food hardness on these anomalies. However, they rarely considered ontogenetic aspects, while these are crucial for understanding their aetiology during animal growth and how the dental row-jaw complex is affected. Here, we studied the incidence of missing first upper and lower premolars in a French population of captive wild boars to discuss the functional and developmental reasons for missing teeth and to assess the impact of missing teeth on the growth of the dental row-jaw complex. Using the CT-scan data of the cranium and mandible of 24 wild boars investigated six times each during their growth, and presenting a balanced sex ratio, we recorded the number of missing teeth. We then quantified the shape of the upper and lower jaws using 3D geometric morphometrics. We found a similar prevalence of missing first premolar (37.5%) between the upper and the lower jaws, which is higher than the frequencies observed in most continental populations of wild boars. The increasing number of anomalies during ontogeny suggests a relaxed constraint on the dentition associated with a different feeding behaviour in captivity. The absence of first premolars does not appear to be associated with size variation or sexual dimorphism, nor does it affect the place of the dentition within the jaw, the latter being more influenced by the dimorphic shape of the canines and the timing of dental eruption.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950283","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":"Vascular and Osteological Morphology of Expanded Digit Tips Suggests Specialization in the Wandering Salamander (Aneides vagrans)","authors":"Christian E. Brown,&nbsp;William P. Goldenberg,&nbsp;Olivia M. Hinds,&nbsp;Mary Kate O'Donnell,&nbsp;Nancy L. Staub","doi":"10.1002/jmor.70026","DOIUrl":"10.1002/jmor.70026","url":null,"abstract":"<p>For over a century researchers have marveled at the square-shaped toe tips of several species of climbing salamanders (genus <i>Aneides</i>), speculating about the function of large blood sinuses therein. Wandering salamanders (<i>Aneides vagrans</i>) have been reported to exhibit exquisite locomotor control while climbing, jumping, and gliding high (88 m) within the redwood canopy; however, a detailed investigation of their digital vascular system has yet to be conducted. Here, we describe the vascular and osteological structure of, and blood circulation through, the distal regions of the toes of <i>A. vagrans</i> using histology in tandem with live-animal videos. Specifically, we sectioned a toe of <i>A. vagrans</i> at 0.90 μm, embedded it in Spurrs resin, and stained the tissue with toluidine blue. An additional three toes were sectioned at 10 μm, embedded in paraffin, and after sectioning and mounting, treated with Verhoeff and Quad stains. For living salamanders, we recorded real-time videos of blood flowing within individual toes upon a translucent surface oriented both horizontally (0°) and vertically (90°) to simulate both prostrate and vertical clinging scenarios, then analyzed the image sequences using ImageJ. We found that the vascularized toe tips have one large sinus cavity that is divided more proximally into two chambers via a septum, and there are mucous and granular glands in the dorsal and dorsolateral integument of the digit tips. Live-animal trials revealed variable sinus-filling both within and between toes, seemingly associated with variable pressure applied to the substrate when standing, stepping, clinging, and climbing. We conclude that <i>A. vagrans</i>, and likely other climbing salamanders, can functionally fill, trap, and drain the blood in their vascularized toe tips to optimize attachment, detachment, and complex arboreal locomotion (e.g., landing after gliding flight). Such an adaptation could provide insights for bioinspired designs.</p>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11711880/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950284","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":"Middle Ear Mechanics in the Barn Owl","authors":"John Peacock,&nbsp;Monica A. Benson,&nbsp;Daniel J. Field,&nbsp;Garth M. Spellman","doi":"10.1002/jmor.70020","DOIUrl":"10.1002/jmor.70020","url":null,"abstract":"<p>The barn owl is a common research subject in auditory science due to its exceptional capacity for high frequency hearing and superb sound source localization capabilities. Despite longstanding interest in the auditory performance of barn owls, the function of its middle ear has attracted remarkably little attention. Here, we report the middle ear transfer function measured by laser Doppler vibrometry and direct measurements of inner ear pressures. Our results illustrate that the barn owl middle ear produces a pressure gain between the ear canal and the inner ear vestibule of up to 35 dB, which is comparable to that seen in mammals. The footplate velocity transfer function magnitudes overlap with those measured in other bird species, however the differences in phase between the footplate velocity and the sound pressure stimulus indicate a middle ear group delay that is notably shorter than other birds. This work brings us closer to a more complete understanding of the physiology of hearing in a model organism in auditory science.</p>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11699225/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142927364","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":"An Atlas of Anatomical Variants of the Human Talus","authors":"Samuel James Cockerill,&nbsp;Matilde Arnay-de-la-Rosa,&nbsp;Emilio González-Reimers","doi":"10.1002/jmor.70023","DOIUrl":"10.1002/jmor.70023","url":null,"abstract":"<div>\u0000 \u0000 <p>Anatomical variants can be used effectively to identify relationships between individuals in kinship analysis and they may be useful during surgical procedures. These procedures can be better implemented when the cause, appearance and location are understood. Clear representations and definitions of anatomical traits are necessary. A similar morphology of pathologies and variations of normal morphology can lead to confusion and unnecessary intervention. Therefore, there is a considerable need for an anatomical atlas of the particular skeletal elements, such as the talus bone. We have analyzed a total of 925 tali, 591 belonging to different modern and pre-Hispanic samples. Furthermore, 334 tali were analyzed from a reference collection from Athens. We have identified and defined the anatomical variants of the talus bone, of which only some have been mentioned by other researchers. We propose standardized methods that may potentially improve future research in human skeleton anatomy and its applications. We provide information on anatomical variants with the aim of improving their identification, classification and use in medical professions and bioanthropology.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142895216","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}