Journal of Anatomy最新文献

{"title":"Developmental stage ordering yields greater cranial mineralization sequence resolution than embryo size or days since oviposition: A case study using the gekkotan Eublepharis macularius (Blyth, 1854)","authors":"Patrick A. D. Wise,&nbsp;Aaron H. Griffing,&nbsp;Anthony P. Russell","doi":"10.1111/joa.70139","DOIUrl":"10.1111/joa.70139","url":null,"abstract":"<p>Mineralization sequences of cranial elements (often referred to as ossification sequences) are used for a variety of purposes. Believed to be consistent within species (even though they exhibit some variation) and conserved within lineages, they have been assembled using a variety of developmental timetables—absolute time using developmental days; relative time using either increase in size of embryonic dimensions or developmental staging. The relationship between these developmental timetables is unclear in terms of how mineralization sequences are expressed, although they are generally treated as being able to achieve equivalent levels of resolution. Regardless of the developmental timetable employed, mineralization sequences are replete with ties representing simultaneous mineralization of several elements, even though ties are suspected to be rare. Herein we examine the resolution attainable of cranial mineralization events in the leopard gecko by subjecting the same set of embryos, raised under controlled conditions, to sequence analysis using all three of the above-mentioned timetables, with the working hypotheses being that all three would yield the same level of resolution and that we could improve upon the level of resolution attained for gekkotans so far. We found that developmental stage timetabling yielded far less variability in the determination of mineralization sequence as well as considerably better resolution than those for developmental days or embryonic dimensions. We were able to obtain much greater resolution for the leopard gecko than that so far attained for gekkotans for all three developmental timetables, but especially so when ordering the specimens by developmental stage. Furthermore, we found that subdividing embryonic stages into substages (established using additional morphological features) and assessing intensity of staining of mineralizing elements hold promise for achieving improved levels of resolution. Even so, we were only about 55% successful in resolving the cranial mineralization sequence into a series of unique events, indicating that many such events are so closely spaced in developmental time that apparent simultaneity of element mineralization will be challenging to resolve further.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"249 4","pages":"847-864"},"PeriodicalIF":2.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398613/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147480762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scaling relationships between Haversian canal-to-secondary osteon and midshaft femur cortical-to-total area in a human autopsy sample","authors":"Justyna J. Miszkiewicz,&nbsp;Laura A. B. Wilson,&nbsp;Karen M. Cooke,&nbsp;Rita Hardiman","doi":"10.1111/joa.70143","DOIUrl":"10.1111/joa.70143","url":null,"abstract":"<p>Lifestyle variables, including physical activity and diet, are key determinants of bone remodelling. However, remodelling is also spatially limited by the anatomical form of bone. The extent to which these macroscopic, microscopic and lifestyle variables co-vary allometrically in humans is subject to ongoing investigation. We hypothesised that femur midshaft size and biomechanical properties would have a dimensional effect on the size and density of secondary osteons produced during remodelling, independently of age and sex, and that this effect would manifest under different lifestyle conditions. We examined femur midshaft microradiographs in 73 samples part of the Melbourne Femur Research Collection (Australia). We measured cortical/total area (CA/TA) and the ratio of axes of the largest and smallest femur rigidity areas (<i>I</i>_max/<i>I</i>_min); secondary osteon area (On.Ar), the ratio of Haversian canal to On.Ar (H.Ar/On.Ar), and total population density of intact and fragmentary (partially remodelled) secondary osteons (OPD) from the anterior, posterior, medial and lateral anatomical femur axes. Out of all the bone parameters, CA/TA and H.Ar/On.Ar showed low to high negative correlations (<i>p</i> &lt; 0.001, <i>r</i> range − 0.323 to −0.752) and negative allometry relationships in the entire sample, in males and in a sub-group that consisted of individuals who were sedentary but well nourished. In these groups, higher log values of CA/TA were associated with smaller log values of H.Ar/On.Ar, which translated to femoral midshafts with thicker cortices having less porous secondary osteons (smaller Haversian canals relative to thicker lamellar bone). However, this relationship was not evident in females and other age and lifestyle groupings. We suggest that effects of allometry on bone histology, or even basic variables such as cortical thickness, are included in future remodelling and lifestyle assessments to ensure that histological interpretations are not confounded by bone size.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"249 4","pages":"865-882"},"PeriodicalIF":2.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13399104/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147512199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Courtship display behavior influences tail myology in Centrocercus minimus (Gunnison sage-grouse)","authors":"Alexander D. Clark,&nbsp;Jessie Atterholt,&nbsp;Samantha J. Clark,&nbsp;Nathan W. Seward","doi":"10.1111/joa.70089","DOIUrl":"10.1111/joa.70089","url":null,"abstract":"<p>A variety of bird species engage in complicated, elaborate courtship displays to impress potential mates. Such displays include wing flaring, aerial acrobatics, choreographed dances, and tail fanning. Though these behaviors are often well studied, the underlying musculature facilitating them is poorly understood. Exemplars of unique avian courtship behaviors include species of the North American sage-grouse (<i>Centrocercus</i>). Each spring, males gather in leks where they perform courtship displays which incorporate species-specific sound production, nape feather movement, and importantly, the raising and spreading of their rectricial fan for prolonged periods of time. Here we describe the tail myology of the lekking sage-grouse species <i>Ce</i>. <i>minimus</i> (Gunnison sage-grouse). We compare the tail myology of this species to that of other, either closely related or similarly sized, bird species which do not engage in rectricial displays. Results indicate tail myology in <i>Ce</i>. <i>minimus</i> is adapted for unique courtship behaviors. Muscles of the rectricial apparatus in <i>Ce</i>. <i>minimus</i> have greater proportional mass relative to body mass compared to other species examined here, and nearly all other species previously examined. In particular, both overall mass and the mediolateral width of the origination surface of the m. levator caudae are hypertrophied compared to other species which do not incorporate a raised tail fan during courtship displays. Additionally, the muscles that primarily spread the tail fan have relatively more extensive origin surfaces in <i>Ce</i>. <i>minimus</i>. Our results provide evidence that the specialized courtship behaviors of <i>Ce</i>. <i>minimus</i> have a clear influence on the tail myology morphology of this species, and suggest that sexually selected displays alter the corresponding underlying musculature across birds.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"249 4","pages":"705-713"},"PeriodicalIF":2.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13399405/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145700770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Postnatal developmental changes in the laryngeal chemosensory cell clusters of rats","authors":"Sayed Sharif Abdali,&nbsp;Kanna Miyazaki,&nbsp;Takuya Yokoyama,&nbsp;Nobuaki Nakamuta,&nbsp;Tomoyuki Saino,&nbsp;Yoshio Yamamoto","doi":"10.1111/joa.70128","DOIUrl":"10.1111/joa.70128","url":null,"abstract":"<p>Chemosensory cell clusters are taste bud-like sensory structures located in the pharyngo-laryngeal mucosa. These clusters are densely distributed at the entrance of lower airways to detect chemical stimuli and trigger respiratory reflexes; however, their postnatal development remains poorly understood. In this study, we examined postnatal changes in the morphology and distribution of chemosensory clusters in rat laryngeal whole-mount preparations using immunofluorescence for alpha-gustducin (GNAT3, a marker of type II taste cells) and synaptotagmin-1 (Syt1, a marker of type III taste cells). Chemosensory cell clusters were detected along the margin of the epiglottis on postnatal day 2 (PD2). Their numbers rapidly increased by PD7 (26 ± 4.5) and plateaued by postnatal week 3 (PW3, 84.0 ± 4.9), whereas the number of constituent cells continued to increase until PW8. Clusters at early stages (PD2–PD7) contained 2–3 spindle GNAT3-immunoreactive cells and round Syt1-immunoreactive cells. As the cluster matured, both cell types elongated longitudinally, extended the apical tip of their cytoplasmic processes to the epithelial surface, and GNAT3-immunoreactive cells developed branched cytoplasmic processes. P2X3-immunoreactive afferent nerve endings contacted GNAT3- and Syt1-immunoreactive cells throughout development. The results indicate the constant presence of chemosensory cell clusters in the laryngeal entrance and the establishment of neuronal connections as early as PD2. These clusters may be sentinel chemoreceptors at the entrance of the larynx. Because stabilization of chemosensory cell cluster numbers coincides with the weaning period, the postnatal development of these clusters may be associated with feeding behaviors in rats.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"249 4","pages":"769-786"},"PeriodicalIF":2.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398738/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147306164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Secondary cartilage in the murine medial pterygoid plate has a critical role in the pathfinding of the tensor veli palatini","authors":"Luke A. Barlow,&nbsp;Emi Nomura,&nbsp;Abigail S. Tucker","doi":"10.1111/joa.70133","DOIUrl":"10.1111/joa.70133","url":null,"abstract":"<p>The medial pterygoid plate plays a critical role in mammalian craniofacial function during suckling and swallowing. The plate supports the tensor veli palatini (TVP) muscle, which stiffens the soft palate to create a posterior seal. Despite its functional importance, the developmental origins and structural integration of the medial pterygoid plate and associated pterygoid hamulus remain incompletely understood. In this study, we investigated the ontogeny and lineage of the medial pterygoid plate using wildtype and conditional knockout mice with immunofluorescence and lineage tracing. Analysis from embryonic day (E)14.5 to E17.5 confirmed that the medial pterygoid plate formed as a bipartite structure, which later fused to the basisphenoid. The dorsal region of the medial pterygoid plate ossified via Runx2-dependent intramembranous bone formation, while the ventral region formed as a secondary cartilage, undergoing Sox9-dependent chondrogenesis, followed by endochondral ossification. The pterygoid hamulus was evident at E14.5 as a condensation of Sox9-positive mesenchyme at the end of the medial pterygoid plate. Confirming the different modes of development, the ventral and dorsal parts of the medial pterygoid plate showed distinct timing and pattern of collagen remodelling, as shown by B-CHP. Lineage tracing with <i>Wnt1Cre;tdTom</i> and <i>Mesp1Cre;tdTom</i> mice demonstrated that the entire pterygoid process formed from neural crest-derived mesenchyme. In keeping with this, conditional loss of <i>Runx2</i> in the neural crest lineage disrupted ossification of the dorsal part of the medial pterygoid plate, whereas conditional loss of <i>Sox9</i> abolished chondrogenesis of the ventral part of the medial pterygoid plate and the pterygoid hamulus. Notably, TVP muscle fibres were able to maintain their orientation around the residual cartilage in conditional <i>Wnt1creRunx2flfl</i> mutants, while the TVP in conditional <i>Wnt1creSox9flfl</i> mutants formed a ball of cells that failed to extend towards the palatal region. The ventral portion of the medial pterygoid plate and hamulus is therefore required to guide early muscle pathfinding. These findings establish the medial pterygoid plate as a compound craniofacial element with distinct ossification modes and an important role interacting and directing neighbouring tissues.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"249 4","pages":"759-768"},"PeriodicalIF":2.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398515/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147463295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hoffmann's two-toed sloth I: Complete myology in the thoracic limb of Choloepus (Pilosa: Xenarthra)","authors":"C. S. Tucker,&nbsp;A. M. Mossor,&nbsp;J. A. Avey-Arroyo,&nbsp;M. T. Butcher","doi":"10.1111/joa.70134","DOIUrl":"10.1111/joa.70134","url":null,"abstract":"<p>Two- and three-toed sloths are sympatric throughout the neo-tropical rainforests of the Americas. Despite numerous morphological and physiological traits that are convergent, each genus has distinctive ecological and behavioral preferences, including a higher frequency of suspensory walking and posture in two-toed forms. Moreover, complete limb muscle myology is available for only a single species of two-toed sloth, whereas muscle architectural properties are unknown for the genus <i>Choloepus</i>. Part one of this study provides novel descriptions and detailed muscle maps of muscular arrangements for the entire forelimb of Hoffmann's two-toed sloth (<i>C. hoffmanni</i>). Origin, insertion, action, and fiber orientation were documented in 59 forelimb muscles. Several notable features in <i>Choloepus</i> are observed and discussed for their functional implications including: (1) rearrangements to the origin of m. trapezius pars cervicalis and m. biceps brachii short head; (2) a shoulder-elbow muscle chain; (3) extra bellies of the mm. rhomboidei, m. pectorales superficialis, and m. flexor digitorum profundus compared with those same muscles in <i>Bradypus</i>. The observed complexity of muscle traits is suggested to be consistent with the notion of selection for frequent and prolonged suspension (hanging and walking) in two-toed sloths that diverge from more simplified muscular arrangements observed in three-toed sloths, which exhibit a lower frequency of suspensory support and posture. Functional capacities of individual muscles and groups will be determined through quantifications of force, torque, and power in part two of this study to further test this hypothesis.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"249 4","pages":"714-736"},"PeriodicalIF":2.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13398662/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147592291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brain scaling and diversity in musteloids.","authors":"Margot Michaud, Arianna Rose Harrington, Sandrine Ladeveze, Eloy Gálvez-López, Valentin Fischer, Apolline Alfsen, Ornella C Bertrand","doi":"10.1111/joa.70226","DOIUrl":"10.1111/joa.70226","url":null,"abstract":"<p><p>The diversity of brain size and organization across mammals reflects how evolutionary and ecological pressures have shaped neural architecture through time. Yet, how these selective pressures translated into measurable variation in the proportions and overall shape of the brain across species remains poorly understood. In this study, we used high-resolution virtual endocasts from 41 musteloid species (e.g., otters, skunks, raccoons) to quantify variation in endocranial composition and shape. We analyzed both the complete endocast and its principal subdivisions (olfactory bulbs (OB), cerebrum, and hindbrain) using a combination of compositional data analysis and 3D geometric morphometrics. Phylogenetically informed regressions (PGLS) and model comparisons were used to assess the effects of endocranial size, locomotion, diet, and taxonomy on both the regional proportions and the overall shape of the endocranial cast. Musteloid brain organization is mostly driven by size-dependent scaling: larger brains have enlarged cerebra, reduced olfactory and hindbrain regions, and rounder endocasts. However, some lineages markedly deviate from this largely conserved allometry: otters (Lutrinae) exhibit proportionally enlarged cerebra and strongly reduced OB, whereas skunks (Mephitidae) show the reverse pattern, emphasizing enhanced olfactory investment. Feeding ecology also contributes to variation in brain organization, as piscivores show disproportionately smaller OB compared with other feeding guilds. In contrast, locomotor mode has little explanatory power for either endocranial composition or shape. Brain evolution in musteloids is therefore not uniform: a common scaling pattern dominates, but lineage- and diet-specific adjustments modify how brain regions are proportioned.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13501094/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148808554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterodonty in the teeth of the turiasaurian sauropod from Angeac-Charente (Early Cretaceous, southwestern France): Comparison of anatomical and geometric morphometric approaches.","authors":"Clémence Le Gouellec, Ronan Allain, Jean Goedert, Romain Pintore, Jackson Carter, Rafael Royo-Torres, Dominique Augier, Raphaël Cornette","doi":"10.1111/joa.70230","DOIUrl":"10.1111/joa.70230","url":null,"abstract":"<p><p>Sauropod teeth are often described within a taxonomic framework, with few studies focusing on heterodonty or intraspecific morphological variation. The Lagerstätte of Angeac-Charente has yielded 167 heart-shaped isolated teeth from a single turiasaurian species. Observations of this material during its collection in the field, preparation, and recording in the collections suggest the presence of possible heterodonty in this species. In this study, we analyze this heterodonty using both comparative anatomy and 3D geometric morphometric analyses coupled with machine learning algorithms. Our principal objective is to determine whether one of the two approaches-quantitative or qualitative-is more effective than the other and whether they can be complementary studying heterodonty. The results confirm the presence of heterodonty, with five different morphotypes, which correspond to premaxillary, maxillary anterior, maxillary posterior, anterior dentary, and posterior dentary teeth. An anteroposteriorly decreasing size gradient in the jaw is observed. Qualitative comparative anatomy is the quickest method, with few conflicts in morphotyping, while quantitative approaches might resolve ambiguities through more precise and replicable analyses. Together, these methods provide complementary insights and allow retrospective positioning of teeth within the jaw. This study, therefore, allows for the reliable assignment of teeth to specific regions or positions in turiasaurian sauropods. Such assignment work is also necessary for many other taxa, and this method will, therefore, be useful for future research. Indeed, it is fully applicable to other sauropod taxa, theropods, or crocodilians.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13498781/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A reappraisal of the respiratory vasculature of the electric eel, Electrophorus sp.","authors":"Atsushi Ishimatsu, Mizuri Ishimatsu, Ryoshiro Wakiya, Yu Maekawa, Ryosuke Murata, Umina Kubo, Mark Bayley, Tobias Wang","doi":"10.1111/joa.70229","DOIUrl":"https://doi.org/10.1111/joa.70229","url":null,"abstract":"<p><p>The electric eel (Electrophorus sp.) is an air-breathing teleost and has been known as the only fish taxon with direct vascular connections (shunts) between the ventral and dorsal aortas in all four gill arches. The aerial respiratory capillaries of the electric eel have been assumed to be perfused with the pre-branchial blood from these shunt vessels. We re-examined the cardiovascular anatomy and found these prevailing notions to be partly inaccurate. The gills of Electrophorus varii are of the holobranch structure with the afferent (ABA) and efferent (EBA) branchial arteries as discrete anatomical entities in all gill arches. Although the filaments are much shorter than in typical exclusively water-breathing teleosts, normal filamental vasculature intervenes between ABA and EBA in all arches. Yet, there are anastomoses between ABA and EBA, most notably in the fourth gill arch, where the anastomotic vessels have the same diameter as the parent vessels. There are a few, much thinner anastomotic vessels between ABA and EBA and/or the afferent and efferent filamental arteries in the first and second gill arches. The third arch has no anastomoses. The vascular space in the secondary lamellae consists of six to eight parallel interconnected vessels. Capillaries on the dorsal and lateral surfaces of the air-breathing organ are supplied by the branches of the first and second EBAs, while those on the ventral surface receive blood from the hypobranchial arteries, which originate from EBAs in all of the gill arches. Thus, the entire aerial respiratory capillaries are perfused with the post-branchial blood, not with the pre-branchial blood as previously assumed. Oxygenated blood from the air-breathing organ is drained by the anterior cardinal vein on the dorsal and lateral sides and by the inferior jugular vein on the ventral side. The heart shows no anatomical specialization to separate oxygenated and deoxygenated blood, although there is a peculiar rotation such that the bulbus arteriosus and ventricle occur on the right, while the atrium occupies the left side of the pericardial cavity. Thus, the vascular system in the head region of E. varii deviates little from the typical teleostean configuration, except for the proliferation of aerial respiratory capillaries within the air-breathing organ, a considerable degree of gill regression, and anastomoses in gill vessels. These findings, when coupled with the fact that the electric eel obtains 80% of oxygen requirement from air in normoxic water, suggest that heavy reliance on air-breathing is not a driving force for the restructuring of the central cardiovascular system toward double circulation, in which oxygenated and deoxygenated blood is separated.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13488518/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of alignment and scaling on biological inferences from landmark-free morphometrics.","authors":"Lucy E Roberts, Marco Camaiti, Anjali Goswami","doi":"10.1111/joa.70227","DOIUrl":"10.1111/joa.70227","url":null,"abstract":"<p><p>Recent advances in shape quantification techniques have revolutionised the field of evolutionary morphology by providing a time-efficient alternative to well-established methods such as geometric morphometrics. In particular, landmark-free methods are at the forefront of new developments in shape analysis, but concerns over their reproducibility and sensitivity to non-biological variation have hindered more widespread adoption. A primary source of non-biological bias in shape analysis is misalignment and incorrect scaling of specimens, which can result in capturing anatomically incongruent aspects of shape in otherwise homologous structures. Here, we compare methods for mesh alignment and scaling using a recently described landmark-free approach, Deterministic Atlas Analysis (DAA). We find similarities between morphospaces derived from meshes aligned using most alignment protocols, but with large differences in variance structure. Surprisingly, the largest differences are not found between Procrustes-based and non-Procrustes-based approaches, but between the Procrustes-based method with internal scaling and all other alignment approaches. More broadly, scaling method has the greatest impact on shape variation captured by DAA. Based on these results, we make recommendations to ensure that alignment strategy maintains homology in landmark-free morphometry. As in all morphometric analyses, violating principles of homology can result in spurious or inaccurate biological inferences in macroevolutionary studies of anatomy and must be explicitly considered in designing methodological frameworks.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13478407/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148759026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}