Journal of Morphology最新文献

{"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}

{"title":"A Dark Horse: Colonial System of Integration in Ctenostome Bryozoans (Gymnolaemata: Ctenostomata)","authors":"Natalia Shunatova,&nbsp;Maxim Zhidkov","doi":"10.1002/jmor.70018","DOIUrl":"10.1002/jmor.70018","url":null,"abstract":"<div>\u0000 \u0000 <p>The colonial system of integration (CSI) provides intracolonial nutrient supply in many gymnolaemate bryozoans. In Ctenostomata, its presence is known for species with stolonal colonies, for example, vesicularioideans, but its structure is almost unexplored. The CSI is thought to be absent in alcyonidioideans and other ctenostomes. Here, we present the first detailed description of the CSI ultrastructure in both autozooids and kenozooids of two vesicularioideans, <i>Buskia nitens</i> and <i>Amathia gracilis</i>, and two alcyonidioideans, <i>Alcyonidium hirsutum</i> and <i>Flustrellidra hispida</i>. We revealed differences in the endocyst structure: in studied alcyonioidioideans, it comprises the epidermis, extracellular matrix and coelomic lining, while in the studied vesicularioideans, it includes only the epidermis. In vesicularioidean autozooids, the main CSI cord and the most distal part of the muscular funiculus originate together as a single structure near the caecum apex. However, at a short distance basally, they separate and run to different sites: the main CSI cord reaches the communication pore, and the muscular funiculus attaches to the cystid wall in the proximal part of the autozooids. The CSI in alcyonidioidean autozooids includes a central part, comprising several strands running from the caecum and pylorus to the cystid walls, and a peripheral part, which is located between the epidermis and peritoneum of the cystid walls and reaches the communication pores. The autozooidal CSI in the studied alcyonidioids never reaches kenozooidal communication pores. Nevertheless, the CSI is present in kenozooids of <i>F. hispida</i>; its structure corresponds to that of the peripheral part of the CSI in autozooids. These findings suggest that the CSI likely originated rather early in bryozoan evolution, and its putative initial function is nutrient transport to budding sites and zooids undergoing degeneration-regeneration cycle.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142895212","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":"Potential Evolutionary Convergence in Trophic Adaptations of Two Booidean Snake Lineages as Evidenced by Skull Morphology","authors":"Lorenzo Seneci,&nbsp;Alexander S. Hall,&nbsp;Frank Glaw,&nbsp;Mark D. Scherz","doi":"10.1002/jmor.70011","DOIUrl":"10.1002/jmor.70011","url":null,"abstract":"<div>\u0000 \u0000 <p>Booidean snakes are a diverse and widespread lineage with an intriguing evolutionary and biogeographic history. By means of cranial morphology and osteology, this study investigates the evolutionary convergence in the Neotropical genera <i>Boa</i> and <i>Corallus</i> on the one hand and the Malagasy clade comprising <i>Acrantophis</i> and <i>Sanzinia</i> on the other. We hypothesize that the mostly arboreal <i>Corallus</i> and <i>Sanzinia</i> present larger jaws and longer teeth to keep hold of the prey and resist gravity and torsional forces acting on their skull while hanging from branches, while terrestrial genera such as <i>Acrantophis</i> show thinner jaws with shorter teeth because they can rely on the full length of their coils to immobilize and constrict the prey together with a substrate that supports the whole of their body. Overall, we highlight how booidean snakes can serve as intriguing subjects for the study of contingency, determinism, and opportunity in the evolution of distant lineages both phylogenetically and geographically. We also provide the first complete description of the skull of <i>Boa constrictor</i>.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142895336","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":"Modifiable Clinical Dental Impression Methods to Obtain Whole-Mouth and Detailed Dental Traits From Vertebrates","authors":"Johannes N. Wibisana,&nbsp;Ray A. Sallan,&nbsp;Towa Ota,&nbsp;Pavel Puchenkov,&nbsp;Tai Kubo,&nbsp;Lauren Sallan","doi":"10.1002/jmor.70017","DOIUrl":"10.1002/jmor.70017","url":null,"abstract":"<p>Dental impressions, developed for accurate capture of oral characteristics in human clinical settings, are seldom used in research on nonlivestock, nonprimate, and especially nonmammalian vertebrates due to a lack of appropriate tools. Studies of dentitions in most vertebrate species usually require euthanasia and specimen dissection, microCT and other scans with size and resolution tradeoffs, and/or ad-hoc individual impressions or removal of single teeth. These approaches prevent in-vivo studies that factor in growth and other chronological changes and separate teeth from the context of the whole mouth. Here, we describe a non-destructive method for obtaining high-resolution dentition-related traits that can be used on both living animals and museum specimens for almost all vertebrates, involving a customizable and printable dental impression tray. This method has repeatedly and accurately captured whole-mouth morphology and detailed features at high resolution in the living non-teleost actinopterygian fish, <i>Polypterus senegalus</i>, in a laboratory setting. It can be used for comparative morphology and to observe temporal changes such as the presence of microwear, tooth replacement rates, and occlusal and morphological changes through ontogeny.</p>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11669741/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142895322","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":"Histological Study of Skin Structures From Selected Body Areas in the Varanus komodoensis","authors":"A. Lipińska,&nbsp;M. Tarnowska,&nbsp;M. Janeczek,&nbsp;P. Jawień,&nbsp;K. Goździewska-Harłajczuk,&nbsp;J. Klećkowska-Nawrot,&nbsp;L. Hrabska,&nbsp;P. Kuropka","doi":"10.1002/jmor.70021","DOIUrl":"10.1002/jmor.70021","url":null,"abstract":"<div>\u0000 \u0000 <p>The skin of the Komodo dragon (<i>Varanus komodoensis</i>) is covered by a form of armour formed mainly of scales, which often co-occur with osteoderms. Scales are keratinized, non-mineralized structures in the uppermost layer of the epidermis that are in contact with each other to form a system in which individual scales are isolated from each other by a softer skin fold zone. In the <i>Varanus</i>, the surface of the scales is flat and smooth (thoracic limb, abdomen, and tail areas), domed and smooth (head area) or domed with conical ornamentation (dorsal surface, pelvic limb—dorsal surface areas). In contrast, osteoderms are mineralized structures that are an integral part of the skin, located below the epidermal surface and positioned parallel (head, tail, thoracic limb-dorsal surface, thoracic limb-palmar surface, and tail) or obliquely (pelvic limb-dorsal surface, groin, abdomen) to the surface. Regardless of the body region, osteoderms are structures that are completely anchored in the dermis, and their surface is smooth and devoid of ornamentation. Tangential sections of the osteoderms demonstrate concentric resting lines. Histological sections of the varanid dermis show the presence of collagen bundles, parallel interlacing or crossing bundles of collagen fibers of varying thickness and degree of compactness, accompanied by muscle fibers. In the area of skin close to the osteoderm, loosely arranged bundles of collagen fibers are present, while in the zone distal to the osteoderm, a compact arrangement of these fibers is present. This study documents the morphological diversity and distribution of osteoderms and scales in selected areas of the body of <i>V. komodoensis</i>. Scales are characterized by a high polymorphism related to body region, while osteoderms show a high morphological similarity independent of the area of occurrence.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142895160","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":"Analyzing the Life History of Caimans: The Growth Dynamics of Caiman latirostris From an Osteohistological Approach","authors":"Pereyra Maria Eugenia,&nbsp;Paula Bona,&nbsp;Pablo Siroski,&nbsp;Anusuya Chinsamy","doi":"10.1002/jmor.70010","DOIUrl":"10.1002/jmor.70010","url":null,"abstract":"<p>Skeletochronology and growth dynamics are intensively investigated in vertebrate osteohistology. These techniques are particularly important for interpreting the life history of long-lived species, such as crocodilians. To understand the longevity, growth dynamics, sexual maturity, and sexual dimorphism of caimans we studied an almost complete ontogenetic series of captive and wild specimens of <i>Caiman latirostris</i> from different localities of Argentina. We identified both cyclical and noncyclical growth marks in juvenile caimans, and we suggest that the latter are associated with environmental stress. By overlapping the growth marks of different individuals, we were able to estimate the minimum age of each specimen. Variations in growth rate are evident in different bones, with the femur and scapula having the highest growth rates, while the fibula and pubis have much slower growth rates. We were able to determine the approximate age of sexual maturity from growth curves deduced from osteohistology, which concurred with those assessed in ecological studies. Additionally based on the growth curves we were able to document different growth dynamics which may be related to sexual dimorphism. This study provides valuable insights into the life history and ecological dynamics of crocodilians, shedding light on their growth patterns, attainment of sexual maturity, and the influence of environmental factors on growth. Furthermore it documents the intraspecific and interelemental osteohistological variation in crocodilians and has direct implications for studies that assess the life history of extinct archosaurs and other sauropsids.</p>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jmor.70010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142846727","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":"Frog Fibres: What Muscle Architecture Can Tell Us About Anuran Locomotor Function","authors":"Alice Leavey,&nbsp;Christopher T. Richards,&nbsp;Laura B. Porro","doi":"10.1002/jmor.70016","DOIUrl":"10.1002/jmor.70016","url":null,"abstract":"<p>Muscle fibre architecture is an important aspect of anatomy to consider when estimating muscle properties. How fibre architecture varies across species specialising in different locomotor functions is not well understood in anurans, due to difficulties associated with fibre extraction in small animals using traditional methods. This paper presents the first digital analysis of fibre architecture in frogs using an automated fibre-tracking algorithm and contrast-enhanced µCT scans. We find differences in hindlimb muscle fibre architecture between frogs specialising in different locomotor modes, as well as examples of many-to-one mapping of form to function. The trade-off between fibre length and muscle physiological cross-sectional area, and therefore contractile speed, range of motion and muscle force output, differs significantly between jumpers and swimmers, but not walker-hoppers. Where species place on this functional spectrum of fibre architecture largely depends on the muscle being examined. There is also some evidence that fibre length may be adjusted to increase contractile speed without undertaking the metabolically expensive process of growing and maintaining larger muscles. Finally, we make a detailed outline of the remaining gaps in our understanding of anuran fibre architecture that can now be addressed with this valuable digital method in future research.</p>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"286 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jmor.70016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142846740","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":"Spermatozoa and Spermatogenesis in the Ribbon Worm Asteronemertes gibsoni (Hoplonemertea, Oerstediidae), a Symbiont of Sea Stars","authors":"Olga V. Yurchenko,&nbsp;Alexey V. Chernyshev","doi":"10.1002/jmor.70014","DOIUrl":"10.1002/jmor.70014","url":null,"abstract":"<div>\u0000 \u0000 <p>In the phylum Nemertea, the class Hoplonemertea (former Enopla) comprises the largest number of studied species with complex spermatozoa. <i>Asteronemertes gibsoni</i> Chernyshev, 1991, a nemertean species having a symbiotic relationship with sea stars, is characterized by complex filiform spermatozoa. Here, spermatogenesis and spermatozoon structure in <i>A. gibsoni</i> have been examined using light and electron microscopy. Numerous proacrosomal vesicles of two kinds have been found in early spermatogenic cells. In spermatozoa, the elongated acrosomal complex consists of two components: a core, which is a spindle-shaped electron-dense acrosomal vesicle with a long anterior end, and its casing of moderate electron density that covers the acrosomal vesicle completely. The acrosomal complex is located laterally relative to the elongated nucleus. The acrosomal casing bears two rows of small, short channels between the nucleus and the electron-dense acrosomal core. In late spermatids, the elongations of the acrosomal complex and the nucleus occur simultaneously and are mediated by numerous microtubules that disappear during the latest stages of spermiogenesis. The flagellum in spermatogenic cells and spermatozoa contains an axoneme with the usual 9 × 2 + 2 microtubular organization and is posteriorly oriented in spermatozoa. As known to date, <i>A. gibsoni</i> has the most modified spermatozoa among investigated Nemertea, and the complex structure of its sperm is suggested to be associated with the reproductive biology, in particular, with fertilization. Additionally, a number of similar ultrastructural features in spermatozoon organization have been found in <i>A. gibsoni</i> and <i>Kurilonemertes phyllospadicola</i> whose phylogenetic relationship was previously proven.</p></div>","PeriodicalId":16528,"journal":{"name":"Journal of Morphology","volume":"285 12","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807323","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}