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Royal Society Open Science Nov 2022The evolution of morphological diversity has held a long-standing fascination among scientists. In particular, do bodies evolve as single, integrated units or do...
The evolution of morphological diversity has held a long-standing fascination among scientists. In particular, do bodies evolve as single, integrated units or do different body parts evolve semi-independently (modules)? Suckermouth armoured catfishes (Loricariidae) have a morphology that lends nicely to evolutionary modularity and integration studies. In addition to a ventrally facing oral jaw that directly contacts surfaces, the neurocranium and pectoral girdle are fused, which limits movement of the anterior part of the body. Functional constraints suggest it is likely the head and post-cranial body act as separate modules that can evolve independently. If true, one would expect to see a two- or three-module system where the head and post-cranial body are morphologically distinct. To test this hypothesis, we quantified shape using geometric morphometric analysis and assessed the degree of modularity across functionally important regions. We found the armoured catfish body is highly modularized, with varying degrees of integration between each module. Within subfamilies, there are different patterns of evolutionary modularity and integration, suggesting that the various patterns may have driven diversification along a single trajectory in each subfamily. This study suggests the evolution of armoured catfish diversification is complex, with morphological evolution influenced by interactions within and between modules.
PubMed: 36425524
DOI: 10.1098/rsos.220713 -
Anatomy & Cell Biology Mar 2023Agenesis or congenital hypoplasia of skeletal muscles occurs infrequently but may occur with specific conditions such as Poland syndrome. The trapezius muscle can vary...
Agenesis or congenital hypoplasia of skeletal muscles occurs infrequently but may occur with specific conditions such as Poland syndrome. The trapezius muscle can vary in the extent of its bony attachments or may have additional slips, however congenital absence or hypoplasia is extremely rare. There are only a few reports of partial or complete absence of the trapezius muscle. Two cases of bilateral absence of the trapezius were both in males and were accompanied by the absence of additional muscle in the pectoral girdle. Herein, we describe a case of a 56-year-old male cadaver with bilateral hypoplasia of the trapezius. The muscle was largely represented by atrophied muscle fibers with an abundance of fibrotic or fatty connective tissue. This subject had very minor hypoplasia of the left pectoralis major muscle, but the remaining muscles of the pectoral girdle were normal. The spinal accessory nerve terminated in the sternocleidomastoid muscle on both sides, failing to reach the trapezius. We interpret these findings to be consistent with a minor variant of Poland syndrome.
PubMed: 36263506
DOI: 10.5115/acb.22.139 -
Ecology and Evolution Oct 2022Ecological character displacement between the sexes, and sexual selection, integrate into a convergent set of factors that produce sexual variation. Ecologically...
Sexually mediated phenotypic variation within and between sexes as a continuum structured by ecology: The mosaic nature of skeletal variation across body regions in Threespine stickleback ( L.).
Ecological character displacement between the sexes, and sexual selection, integrate into a convergent set of factors that produce sexual variation. Ecologically modulated, sexually mediated variation within and between sexes may be a major contributor to the amount of total variation that selection can act on in species. Threespine stickleback () display rapid adaptive responses and sexual variation in many phenotypic traits. We examined phenotypic variation in the skull, pectoral and pelvic girdles of threespine stickleback from two freshwater and two coastal marine sites on the Sunshine Coast of British Columbia, Canada, using an approach that avoids a priori assumptions about bimodal patterns of variation. We quantified shape and size of the cranial, pectoral and pelvic regions of sticklebacks in marine and freshwater habitats using 3D geometric morphometrics and an index of sexually mediated variation. We show that the expression of phenotypic variation is structured in part by the effects of both habitat marine vs freshwater and the effects of individual sites within each habitat. Relative size exerts variable influence, and patterns of phenotypic variation associated with sex vary among body regions. This fine-grained quantification of sexually mediated variation in the context of habitat difference and different anatomical structures indicates a complex relationship between genetically inferred sex and environmental factors, demonstrating that the interplay between shared genetic background and sexually mediated, ecologically based selective pressures structures the phenotypic expression of complex traits.
PubMed: 36254299
DOI: 10.1002/ece3.9367 -
Mymensingh Medical Journal : MMJ Oct 2022Clavicle is an upper limb locomotory bone which helps in formation of pectoral girdle and connected the upper limb with axial skeleton. There is no baseline data of...
Clavicle is an upper limb locomotory bone which helps in formation of pectoral girdle and connected the upper limb with axial skeleton. There is no baseline data of clavicle in contrast to demographic variation in our country, so the study was designed to obtain baseline data on clavicle for anthropological, forensic and clinical use. This descriptive cross-sectional study was done among 150 (65 right and 85 left) fully ossified dry human clavicle in Mymensingh Medical College, Mymensingh, Bangladesh from January 2020 to December 2020. Sample was collected by the help of nonrandom purposive sampling technique from Department of Anatomy of Mymensingh Medical College and Community Based Medical College, Bangladesh, Mymensingh. The parameters were the antero-posterior diameter and vertical diameter of sternal and acromial ends of clavicle, measured with the help of digital vernier slide caliper and expressed in millimeter. In the current study the mean±SD antero-posterior diameter of sternal end of 65 clavicles of right side was 21.97±2.889mm and 85 clavicles of left side were 20.30±3.459mm. The mean±SD antero-posterior diameter of acromial end of 65 right sided clavicles was 21.96±5.161mm and 85 clavicles of left side were 21.00±4.002mm. Correlation was done in between antero-posterior diameter and vertical diameter of sternal end of clavicle and the differences were highly significant on both sides. Similarly, when correlation was done for the acromial end of clavicle the difference was found non-significant on right side and highly significant on left side.
Topics: Bangladesh; Clavicle; Cross-Sectional Studies; Humans; Osteogenesis; Sternum
PubMed: 36189530
DOI: No ID Found -
Clinical Anatomy (New York, N.Y.) Mar 2023Knowledge of musculoskeletal anatomy is fundamental to physical therapy education. Although detailed anatomy syllabi have been developed for medical and other health...
Knowledge of musculoskeletal anatomy is fundamental to physical therapy education. Although detailed anatomy syllabi have been developed for medical and other health professional students, none are available for training physical therapists. Therefore, the aim of this project was to produce a core musculoskeletal anatomy syllabus specific to physical therapy students, utilizing a modified Delphi approach. An international Delphi panel (n = 53) composed of anatomists and clinicians involved in physical therapy education considered a total of 2193 anatomical items arranged in four categories (musculoskeletal concepts; vertebral column; pectoral girdle and upper limb; pelvic girdle and lower limb). Using specific criteria, items were rated on the basis of whether they were considered essential knowledge for a competent physical therapy student, and were categorized as core, recommended, not recommended or not core. Of the 2193 items, 1700 (77.5%) were rated as core or recommended. For musculoskeletal concepts, 70% (233/332) of items were categorized as core/recommended. Approximately 80% of items in the other three categories were considered core/recommended-vertebral column (355/440), pectoral girdle and upper limb (513/657), and pelvic girdle and lower limb (599/764). This project presents a detailed musculoskeletal anatomy syllabus which may be used within a physical therapy curriculum. A key difference compared to published musculoskeletal anatomy syllabi for medical students is that a greater number of items are considered core/recommended (approximately 80% vs. 50%). These findings will now be considered and deliberated in accordance with the International Federation of Associations of Anatomists modified Delphi approach.
Topics: Humans; Curriculum; Education, Medical, Undergraduate; Students, Medical; Anatomists; Spine; Anatomy
PubMed: 36177764
DOI: 10.1002/ca.23953 -
Journal of Anatomy Dec 2022Stereospondyli are a clade of large aquatic temnospondyls known to have evolved a large dermal pectoral girdle. Among the Stereospondyli, metoposaurids in particular...
Stereospondyli are a clade of large aquatic temnospondyls known to have evolved a large dermal pectoral girdle. Among the Stereospondyli, metoposaurids in particular possess large interclavicles and clavicles relative to the rest of the postcranial skeleton. Because of the large size of these dermal bones, it was first proposed that they served as ballast during hydrostatic buoyancy control which assisted metoposaurids to live a bottom-dwelling mode of life. However, a large bone need not necessarily be heavy, for which determining the bone compactness becomes crucial for understanding any such adaptation in these dermal bones. Previous studies on the evolution of bone adaptations to aquatic lifestyles such as osteosclerosis, pachyostosis, osteoporotic-like pattern and pachyosteosclerosis have been observed in the long bones of secondarily aquatic amniotes. However, there are no known studies on the analysis of bone compactness in the dermal pectoral girdle of non-amniote taxa including Temnospondyli. This study looks at evidence of changes in bone mass adaptations in the dermal bones of the pectoral girdle of two stereospondyls occurring in the Late Triassic Krasiejόw locality (Southwestern Poland), namely: Metoposaurus krasiejowensis and Cyclotosaurus intermedius. However, because of lack of research on bone compactness of temnospondyls in general, there is no existent frame of reference to infer bone mass increase (BMI) in the M. krasiejowensis samples, and thus the bone compactness results of this taxon are compared with that of the samples of C. intermedius. Results of this study indicate that the interclavicles of M. krasiejowensis partially evolved BMI-like condition rendering these bones to be heavy enough to get selected as ballast during hydrostatic buoyancy control. Additionally, M. krasiejowensis shared its habitat with C. intermedius, however, the dermal pectoral girdle sample of the latter taxon does not display signs of BMI-like condition. Furthermore, the absence of variation in hydrostatic buoyancy control in the ontogenetic series of interclavicles of M. krasiejowensis could imply lack of ontogenetic niche shift along the water column.
Topics: Animals; Amphibians; Bone and Bones; Bone Density; Adaptation, Physiological; Clavicle; Biological Evolution; Fossils
PubMed: 36165276
DOI: 10.1111/joa.13755 -
Zootaxa Jun 2022A new species of Microlepidogaster is described from rio Pardo drainage, a coastal basin in eastern Brazil. This species can be differentiated from its congeners by...
A new species of Microlepidogaster is described from rio Pardo drainage, a coastal basin in eastern Brazil. This species can be differentiated from its congeners by having the following unique features: 1) anterior portion of snout with a large odontode-free band extending laterally from the anterior tip of snout to the postrostral plate 2; 2) transverse process of second dorsal-fin pterygiophore exposed and bearing odontodes; and 3) exposed area of pectoral girdle extended to the mesial symphysis, with odontodes mainly distributed in the coracoid ventral expansion. The new species is further distinguished by several other morphological non-exclusive features. Recently, some Microlepidogaster species were reallocated to Rhinolekos. The taxonomic changes involving these genera is herein discussed.
Topics: Animals; Brazil; Catfishes; Lepidoptera
PubMed: 36095748
DOI: 10.11646/zootaxa.5150.2.6 -
International Journal of Environmental... Aug 2022Children are exposed to multiple factors that contribute to an increase in body mass and the development of posture defects. The aim of the study is to assess the...
Children are exposed to multiple factors that contribute to an increase in body mass and the development of posture defects. The aim of the study is to assess the relationship between the segmental distribution of fat mass and muscle mass and the incidence of body posture abnormalities in early school-aged children. A total of 190 children aged 7-9 were included in the research project. The examined children were divided according to age (class level) into three groups. Height, weight and body composition, BMI, and body posture were determined. Thoracic and lumbar spine abnormalities occurred most frequently in the examined children (7-95%, 8-92%, 9-89.5%). During the assessment of the segmental body composition, the lowest fat-fat-free index was found in the trunk. The number of abnormalities of the cervical spine, pelvis, and lower extremities increases with age. The number of abnormalities of the thoracic and lumbar spine, as well as of upper extremities and the pectoral girdle decreases with age. Body posture abnormalities are correlated with body composition and in particular with the fat mass percentage. The segmental body com-position analyzer can be used to screen for posture defects.
Topics: Body Composition; Body Mass Index; Child; Humans; Incidence; Lumbar Vertebrae; Posture
PubMed: 36078524
DOI: 10.3390/ijerph191710815 -
Scientific Reports Aug 2022The sternum is a stabilizing element in the axial skeleton of most tetrapods, closely linked with the function of the pectoral girdle of the appendicular skeleton.... (Review)
Review
The sternum is a stabilizing element in the axial skeleton of most tetrapods, closely linked with the function of the pectoral girdle of the appendicular skeleton. Modern mammals have a distinctive sternum characterized by multiple ossified segments, the origins of which are poorly understood. Although the evolution of the pectoral girdle has been extensively studied in early members of the mammalian total group (Synapsida), only limited data exist for the sternum. Ancestrally, synapsids exhibit a single sternal element and previously the earliest report of a segmental sternum in non-mammalian synapsids was in the Middle Triassic cynodont Diademodon tetragonus. Here, we describe the well-preserved sternum of a gorgonopsian, a group of sabre-toothed synapsids from the Permian. It represents an ossified, multipartite element resembling the mammalian condition. This discovery pulls back the origin of the distinctive "mammalian" sternum to the base of Theriodontia, significantly extending the temporal range of this morphology. Through a review of sternal morphology across Synapsida, we reconstruct the evolutionary history of this structure. Furthermore, we explore its role in the evolution of mammalian posture, gait, and ventilation through progressive regionalization of the postcranium as well as the posteriorization of musculature associated with mammalian breathing.
Topics: Biological Evolution; Fossils; Locomotion; Respiration; Sternum
PubMed: 35931742
DOI: 10.1038/s41598-022-17492-6 -
Integrative Organismal Biology (Oxford,... 2022During locomotion, cervical muscles must be active to stabilize the head as the body accelerates and decelerates. We hypothesized that cervical muscles are also part of...
During locomotion, cervical muscles must be active to stabilize the head as the body accelerates and decelerates. We hypothesized that cervical muscles are also part of the linked chain of axial muscles that provide core stabilization against torques applied to the hip joint by the extrinsic muscles of the legs. To test whether specific cervical muscles play a role in postural stabilization of the head and/or core stabilization of the pelvic girdle, we used surface electromyography to measure changes in muscle activity in response to force manipulations during constant speed running and maximum effort counter-movement jumps. We found that doubling the mass of the head during both running and maximum effort jumping had little or no effect on (1) acceleration of the body and (2) cervical muscle activity. Application of horizontal forward and rearward directed forces at the pelvis during running tripled mean fore and aft accelerations, thereby increasing both the pitching moments on the head and flexion and extension torques applied to the hip. These manipulations primarily resulted in increases in cervical muscle activity that is appropriate for core stabilization of the pelvis. Additionally, when subjects jumped maximally with an applied downward directed force that reduced acceleration and therefore need for cervical muscles to stabilize the head, cervical muscle activity did not decrease. These results suggest that during locomotion, rather than acting to stabilize the head against the effects of inertia, the superficial muscles of the neck monitored in this study help to stabilize the pelvis against torques imposed by the extrinsic muscles of the legs at the hip joint. We suggest that a division of labor may exist between deep cervical muscles that presumably provide postural stabilization of the head versus superficial cervical muscles that provide core stabilization against torques applied to the pelvic and pectoral girdles by the extrinsic appendicular muscles.
PubMed: 35854827
DOI: 10.1093/iob/obac021