Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology最新文献

Birds have extremely flexible necks, which help in their search for food. However, studies on the variation in bird cervical anatomy and its relationship with foraging are rare, despite the different habits presented between species. Here, we analyze the anatomy of the neck of aquatic birds and relate it to their foraging strategies. We dissected specimens representing four species of Charadriiformes, 11 species of Phaethoquornithes, and two specimens belonging to the outgroup Telluraves. We chose to emphasize Charadriiformes and Phaethoquornithes because they present several strategies that require cervical mobility and stability. We note that vertebral anatomy and dimensions vary, which affects the shape and size of the soft tissues attached throughout the neck. The synovial cartilage present in the articulatio intercorporalis represents an additional length in the neck, however, this is not longer than that observed in animals with intervertebral discs. Our analysis indicates that birds have a prevalence of dorsoventral movements in the middle of the neck and lateral and rotational movements near the base of the neck, while the region near the head presents a wide range of movement in all directions. Cervical ligaments and muscles throughout the neck provide stability in all segments, although the robustness of the soft tissues indicates that the most caudal portion of the neck is the most stable. The vertebral and soft tissue anatomy is consistent with the extensive mobility in pitching, yaw, and roll movements performed mainly by the head and first segment of the neck during the different foraging of the analyzed birds. Furthermore, the muscles closer to the skull are robust and allow the execution of a variety of habits to capture food in different species. The subsequent cervical segments present differences that explain their reduction in mobility, but they are equally stable.

The Permian mesosaurs are well known for being the earliest amniotes to exhibit adaptations for living in a marine environment (Irati-Whitehill Sea). In addition to their set of skeletal features associated with aquatic dwelling life, their dentition includes important characteristics related to feeding in this habitat, which is described in this work, based on the analysis of mesosaur specimens from the Lower Permian Irati Formation of Brazil. Mesosaurs have several slender, conical teeth bordered by enamel apicobasal ridges, a feature predominantly found in aquatic amniotes. Internally, the dentine walls are formed by the arrangement of layers of orthodentine and globular dentine. To prevent tooth loss, the basal area is equipped with plicidentine, a particular type of orthodentine, allied with cementum, alveolar bone trabeculae, and periodontal space that reinforces anchorage and provides some flexibility. The teeth are replaced in a labio-vertical path, and the dentition replaces alternately. This feature is regarded as plesiomorphic, and it ensures the oral cavity is supplied with enough teeth. However, these features do not the assessment of whether mesosaurs teeth were capable of piercing prey with resistant tegument. Instead, we interpret this adaptation as a mechanism for catching prey, at least in adults, and we endorse a possible ontogenetic dietary shift from small to large forms.

Pusch, L. C., Kammerer, C. F., & Fröbisch, J. (2024). The origin and evolution of Cynodontia (Synapsida, Therapsida): Reassessment of the phylogeny and systematics of the earliest members of this clade using 3D-imaging technologies. The Anatomical Record, 307(4), 1634–1730. https://doi.org/10.1002/ar.25394

In the originally published article, funding information was omitted from the Acknowledgments section. The section should have included the following: We would additionally like to thank the Palaeontological Scientific Trust (PAST), GENUS – DST-NRF Centre of Excellence in Palaeosciences, and the DST-NRF African Origins program for financial support of J. Benoit who shared the respective CT scans with us we mentioned in Acknowledgments.

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A new genus and two new species, Tholimantispa zuoae gen. et sp. nov. and Mantispidipterella curvis sp. nov. are described from the Upper Cretaceous of northern Myanmar amber collected in 2015. Tholimantispa zuoae gen. et sp. nov. is characterized by its distinct pterostigma, broad costal space, bifurcate humeral veinlets, and so forth, and Mantispidipterella curvis sp. nov. is different from Mantispidipterella longissima Liu, Lu et Zhang, 2017 in its ScP (subcosta posterior) distinctly curved at fusing point with RA (radius anterior), RP (radius posterior) abruptly and angularly curved at ra-rp (crossvein between RA and RP), AA3 (third branches of the anterior anal vein) present. The new fossil species enrich the diversity of Dipteromantispidae in the Cretaceous.

The individual Geoffroy's side-necked turtle, Phrynops cf. P. geoffroanus, was diagnosed postmortem with osteosarcoma associated with the forelimb through morphological and histological analysis. Osteosarcoma stands as the most prevalent primary malignant bone tumor in tetrapods. The tumor presents itself as a large mass in the distal epiphysis, characterized by spicular outgrowths and a rugose external texture. Histologically, the afflicted humerus displayed a high degree of vascularity and exhibited an extensive bone resorption process involving the medullary and endosteal regions. Notably, a clear transition between the bone marrow and cortical bone was absent, indicative of a remodeling process featuring Haversian bone system apposition. Additionally, the diaphyseal region displayed the progression of neoplastic bone tissue along the bone. For comparative purposes, we describe a humeral thin section from a healthy specimen revealing compact primary bone interrupted by cyclical growth marks which differs from the continuous growth observed in the neoplastic humerus. To assess the neoplastic bone growth rate at the mid-diaphysis level, phylogenetic eigenvector maps (PEM) were employed, utilizing osteocyte density and vascular density as explanatory variables. The findings indicated that the osteosarcoma exhibited a slow-growing nature, suggesting that the turtle had to live with this condition for years. As the neoplasia continued to expand, it likely led to disadvantages for the pathological Phrynops individual due to humeral deformity. Furthermore, malignancy was associated with angiogenesis and the invasion of the medullary region by neoplastic bone tissue, raising the likelihood of metastasis as an additional factor contributing to the individual's sickness. The presence of numerous vascular canals in the diaphyseal thin section suggested a low-grade central osteosarcoma. It is worth noting that osseous neoplasms are rarely documented in Testudines, making this case of osteosarcoma in a South American freshwater chelid specimen a unique and rare occurrence.

Hyperostosis frontalis interna (HFI) is a human skeletal lesion characterized by nodules of hyperplastic bone and thickening of the frontal bone's inner surface. Despite its prevalence in the general population and its long history of observation—it is one of the most frequently observed pathologies in gross anatomy laboratories—HFI's etiology and pathogenesis remain poorly understood. This is largely due to the lack of a thorough survey of its histology across the various stages of its development. Our study has three major aims: (1) assess HFI histology from incipient to advanced lesions; (2) elucidate lamellar and trabecular structure in HFI; and (3) clarify impacts/roles of the dura mater in HFI. Sections of nondecalcified bone provide evidence for two different categories of lesions: (1) stratum lesions, characterized by lamellar-based overall thickening of the internal table, and (2) eruptive lesions, characterized by nodular formations of initially lamellar bone that appear to form the bulk of bone mass in advanced stages. Sections of nondecalcified bone also suggest that for both lesion types, HFI growths begin as deposits of lamellar bone, which are later remodeled into woven bone deposits; our data do not support the hypothesis that lesions begin as a “diploization” of cortical bone as suggested by prior studies. Trichrome-stained sections provide evidence that growing lesions erode through and engulf the dura mater, effectively destroying this tissue layer as they grow laterally and inwardly. Our results indicate possible avenues of research to better understand the root causes of this disorder.

Accipitriformes are diverse in their prey preferences and use their grasping feet for hunting. Little is known about the architectural design of muscles related to grasping among species of different sizes, diets, and foraging behaviors. In the present study, we report quantitative data and analysis of the pelvic musculature of the Japanese sparrowhawk (Accipiter gularis), Eurasian sparrowhawk (Accipiter nisus), common buzzard (Buteo buteo), northern goshawk (Accipiter gentilis), and cinereous vulture (Aegypius monachus). As expected, mass and architecture of the considered muscles were very different between the cinereous vulture and the four other species. The cinereous vulture allocates more mass and physiological cross-sectional area (PCSA) to the proximally inserted flexor muscles, which indicates the rudimentary grasping ability of the foot and is a myological reflection of its carrion preference. Furthermore, in the cinereous vulture, muscles were built with the lowest architectural index (AI) compared with the other species, and the intrinsic foot muscles were short-fibered, which is disadvantageous for rapid manipulation and foot dexterity. The other four species, as a whole, featured large flexor hallucis longus (FHL) muscles and better development of distally inserted flexors, reflecting their predatory lifestyle. Some differences were also found between the species that consumed birds and those that consumed mammals. The two avivorous species were superior in AI and fiber length of the intrinsic foot muscles which are suitable for good hunting speed and digit flexibility, the prerequisition for hunting agile prey.

Previous studies on anuran anomalies predominantly examine isolated cases or focus on external and skeletal features. Our study analyzes a comprehensive sample collected from 1991 to 2017, examining the muscle-tendon system in 24 anuran species across adult, juvenile, and metamorphic stages. This extensive sample size allows us to investigate consistent anomaly patterns across different developmental stages and anuran families, exploring potential common developmental or genetic factors. Our detailed anatomical examination, encompassing musculature, tendons, and skeletal structures, revealed that 21% of the specimens displayed anomalies, a noteworthy finding considering the extensive sample size and duration of the studied sample. Of these anomalies, 17% affected the locomotor system, predominantly in the upper limbs. Key anomalies included, forelimbs and hindlimbs brachydactyly, rotation in forelimbs, partial kyphotic lordosis, and scoliosis. Notably, the digit 4 in the forelimbs and digits 4 and 5 in the hindlimbs were particularly susceptible to teratogenic effects, indicating possible prolonged exposure during development. Our study also uncovered combinations of anomalies and identified a phenotype similar to Poland syndrome. The findings validate the “Logic of Monsters” (LoMo theory) by Alberch, although the name itself may not be deemed appropriate, showing that developmental disruptions in tetrapods are not random but follow distinct sequences and patterns. The name, while unfortunate, accurately reflects the unusual nature of these developmental anomalies. This contributes to the evolving “Evo-Devo-Path” framework, highlighting the study's importance in understanding developmental disruptions in tetrapods.

The nervous system is distinctive as compared to other tissue systems in human body owing to intricate structural organization. Histological studies played a key role in unveiling complex details of nervous tissue. However, the process of developing suitable staining method for nerve cells was arduous and spanned across almost half a century. The present study explored details of the journey involving quest for propitious staining method in neuroanatomy culminating in promulgation of neuron doctrine at the onset of 20th century. Initial efforts involving hematoxylin (including its diverse modifications) and subsequent adoption of analogous dye-based stains (like Nissl's method) had limited success in visualization of different parts of a nerve cell and structural details of nervous tissue. This was due to inability of dye-based stains to penetrate the connective tissue sheath of nervous tissue. Eventually, advent of metallic stains in form of silver impregnation method (Golgi stain), reduced silver impregnation method with gold stain (Cajal's stain) and silver carbonate staining method of Río-Hortega unraveled the structure of nervous tissue. The evolution of staining methods catalyzed the refinement of theories pertinent to constitution of nervous tissue. Golgi's staining led to emergence of reticular theory (neurons exist as a network) and Nissl's staining was the basis of the concept of Nervösen Grau (nerve cells and glial cells are embedded in mass of gray matter). Finally, Cajal's staining method successfully elucidated the complex anatomy of nerve terminals and resulted in emanation of neuron doctrine (neurons exists as individual units with adjacent connections).