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Development of hypobranchial muscles with special reference to the evolution of the vertebrate neck.Zoological Letters 2018The extant vertebrates include cyclostomes (lamprey and hagfish) and crown gnathostomes (jawed vertebrates), but there are various anatomical disparities between these...
BACKGROUND
The extant vertebrates include cyclostomes (lamprey and hagfish) and crown gnathostomes (jawed vertebrates), but there are various anatomical disparities between these two groups. Conspicuous in the gnathostomes is the neck, which occupies the interfacial domain between the head and trunk, including the occipital part of the cranium, the shoulder girdle, and the cucullaris and hypobranchial muscles (HBMs). Of these, HBMs originate from occipital somites to form the ventral pharyngeal and neck musculature in gnathostomes. Cyclostomes also have HBMs on the ventral pharynx, but lack the other neck elements, including the occipital region, the pectoral girdle, and cucullaris muscles. These anatomical differences raise questions about the evolution of the neck in vertebrates.
RESULTS
In this study, we observed developing HBMs as a basis for comparison between the two groups and show that the arrangement of the head-trunk interface in gnathostomes is distinct from that of lampreys. Our comparative analyses reveal that, although HBM precursors initially pass through the lateral side of the pericardium in both groups, the relative positions of the pericardium withrespect to the pharyngeal arches differ between the two, resulting in diverse trajectories of HBMs in gnathostomes and lampreys.
CONCLUSIONS
We suggest that a heterotopic rearrangement of early embryonic components, including the pericardium and pharyngeal arches, may have played a fundamental role in establishing the gnathostome HBMs, which would also have served as the basis for neck formation in the jawed vertebrate lineage.
PubMed: 29468087
DOI: 10.1186/s40851-018-0087-x -
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 -
PloS One 2017The head and anterior trunk region of most actinopterygian fishes is stiffened as, uniquely within vertebrates, the pectoral girdles have a direct and often strong...
The head and anterior trunk region of most actinopterygian fishes is stiffened as, uniquely within vertebrates, the pectoral girdles have a direct and often strong connection through the posttemporal to the posterior region of the skull. Members of the mesopelagic fish family Stomiidae have their pectoral girdle separated from the skull. This connection is lost in several teleost groups, but the stomiids have an additional evolutionary novelty-a flexible connection between the occiput and the first vertebra, where only the notochord persists. Several studies suggested that stomiids engulf significantly large prey items and conjectured about the functional role of the anterior part of the vertebral column; however, there has been no precise anatomical description of this complex. Here we describe a unique configuration comprising the occiput and the notochordal sheath in Aristostomias, Eustomias, Malacosteus, Pachystomias, and Photostomias that represents a true functional head joint in teleosts and discuss its potential phylogenetic implications. In these genera, the chordal sheath is folded inward ventrally beneath its connection to the basioccipital and embraces the occipital condyle when in a resting position. In the resting position (wherein the head is not manipulatively elevated), this condyle is completely embraced by the ventral fold of the notochord. A manual manipulative elevation of the head in cleared and stained specimens unfolds the ventral sheath of the notochord. As a consequence, the cranium can be pulled up and back significantly farther than in all other teleost taxa that lack such a functional head joint and thereby can reach mouth gapes up to 120°.
Topics: Animals; Biological Evolution; Fishes; Head; Joints
PubMed: 28146571
DOI: 10.1371/journal.pone.0170224 -
Scientific Reports Jul 2021The furcula is a distinctive element of the pectoral skeleton in birds, which strengthens the shoulder region to withstand the rigor of flight. Although its origin among...
The furcula is a distinctive element of the pectoral skeleton in birds, which strengthens the shoulder region to withstand the rigor of flight. Although its origin among theropod dinosaurs is now well-supported, the homology of the furcula relative to the elements of the tetrapod pectoral girdle (i.e., interclavicle vs clavicles) remains controversial. Here, we report the identification of the furcula in the birdlike theropod Halszkaraptor escuilliei. The bone is unique among furculae in non-avian dinosaurs in bearing a visceral articular facet in the hypocleideal end firmly joined to and overlapped by the sternal plates, a topographical pattern that supports the primary homology of the furcula with the interclavicle. The transformation of the interclavicle into the furcula in early theropods is correlated to the loss of the clavicles, and reinforced the interconnection between the contralateral scapulocoracoids, while relaxing the bridge between the scapulocoracoids with the sternum. The function of the forelimbs in theropod ancestors shifted from being a component of the locomotory quadrupedal module to an independent module specialized to grasping. The later evolution of novel locomotory modules among maniraptoran theropods, involving the forelimbs, drove the re-acquisition of a tighter connection between the scapulocoracoids and the interclavicle with the sternal complex.
PubMed: 34282248
DOI: 10.1038/s41598-021-94285-3 -
Frontiers in Robotics and AI 2021Animals are incredibly good at adapting to changes in their environment, a trait envied by most roboticists. Many animals use different gaits to seamlessly transition...
Animals are incredibly good at adapting to changes in their environment, a trait envied by most roboticists. Many animals use different gaits to seamlessly transition between land and water and move through non-uniform terrains. In addition to adjusting to changes in their environment, animals can adjust their locomotion to deal with missing or regenerating limbs. Salamanders are an amphibious group of animals that can regenerate limbs, tails, and even parts of the spinal cord in some species. After the loss of a limb, the salamander successfully adjusts to constantly changing morphology as it regenerates the missing part. This quality is of particular interest to roboticists looking to design devices that can adapt to missing or malfunctioning components. While walking, an intact salamander uses its limbs, body, and tail to propel itself along the ground. Its body and tail are coordinated in a distinctive wave-like pattern. Understanding how their bending kinematics change as they regrow lost limbs would provide important information to roboticists designing amphibious machines meant to navigate through unpredictable and diverse terrain. We amputated both hindlimbs of blue-spotted salamanders () and measured their body and tail kinematics as the limbs regenerated. We quantified the change in the body wave over time and compared them to an amphibious fish species, . We found that salamanders in the early stages of regeneration shift their kinematics, mostly around their pectoral girdle, where there is a local increase in undulation frequency. Amputated salamanders also show a reduced range of preferred walking speeds and an increase in the number of bending waves along the body. This work could assist roboticists working on terrestrial locomotion and water to land transitions.
PubMed: 34124171
DOI: 10.3389/frobt.2021.629713 -
Proceedings of the National Academy of... Jan 2023The Carboniferous (358.9 to 298.9 Ma) saw the emergence of marine ecosystems dominated by modern vertebrate groups, including abundant stem-group holocephalans...
The Carboniferous (358.9 to 298.9 Ma) saw the emergence of marine ecosystems dominated by modern vertebrate groups, including abundant stem-group holocephalans (chimaeras and relatives). Compared with the handful of anatomically conservative holocephalan genera alive today-demersal durophages all-these animals were astonishingly morphologically diverse, and bizarre anatomies in groups such as iniopterygians hint at specialized ecological roles foreshadowing those of the later, suction-feeding neopterygians. However, flattened fossils usually obscure these animals' functional morphologies and how they fitted into these important early ecosystems. Here, we use three-dimensional (3D) methods to show that the musculoskeletal anatomy of the uniquely 3D-preserved iniopterygian can be best interpreted as being similar to that of living holocephalans rather than elasmobranchs but that it was mechanically unsuited to durophagy. Rather, had a small, anteriorly oriented mouth aperture, expandable pharynx, and strong muscular links among the pectoral girdle, neurocranium, and ventral pharynx consistent with high-performance suction feeding, something exhibited by no living holocephalan and never clearly characterized in any of the extinct members of the holocephalan stem-group. Remarkably, in adapting a distinctly holocephalan anatomy to suction feeding, is more comparable to modern tetrapod suction feeders than to the more closely related high-performance suction-feeding elasmobranchs. This raises questions about the assumed role of durophagy in the evolution of holocephalans' distinctive anatomy and offers a rare glimpse into the breadth of ecological niches filled by holocephalans in a pre-neopterygian world.
Topics: Animals; Suction; Ecosystem; Skull; Vertebrates; Fishes; Feeding Behavior
PubMed: 36649436
DOI: 10.1073/pnas.2207854119 -
Journal of Anatomy Dec 2018Klippel-Feil syndrome is a congenital vertebral anomaly, which is characterised by the fusion of at least two cervical vertebrae and a clinically broad set of symptoms,...
Klippel-Feil syndrome is a congenital vertebral anomaly, which is characterised by the fusion of at least two cervical vertebrae and a clinically broad set of symptoms, including congenital scoliosis and elevated scapula (Sprengel's deformity). Klippel-Feil syndrome is associated with mutations in MEOX1. The zebrafish mutant choker (cho) carries a mutation in its orthologue, meox1. Although zebrafish is being increasingly employed as fidelitous models of human spinal disease, the vertebral column of Meox1-deficient fish has not been assessed for defects. Here, we describe the skeletal defects of meox1 mutant zebrafish utilising alizarin red to stain bones and chemical maceration of soft tissue to detect fusions in an unbiased manner. Obtained data reveal that meox1 mutants feature aspects of a number of described symptoms of patients who suffer from Klippel-Feil syndrome and have mutations in MEOX1. These include vertebral fusion, congenital scoliosis and an asymmetry of the pectoral girdle, which resembles Sprengel's deformity. Thus, the meox1 mutant zebrafish may serve as a useful tool to study the pathogenesis of the symptoms associated with Klippel-Feil syndrome.
Topics: Animals; Animals, Genetically Modified; Bone and Bones; Disease Models, Animal; Gene Knockout Techniques; Homeodomain Proteins; Humans; Klippel-Feil Syndrome; Zebrafish; Zebrafish Proteins
PubMed: 30277257
DOI: 10.1111/joa.12890 -
Anatomical Record (Hoboken, N.J. : 2007) Sep 2016To investigate the morphology and evolutionary origin of muscles in vertebrate limbs, we conducted anatomical dissections, computed tomography and kinematic analyses on...
The pectoral fin muscles of the coelacanth Latimeria chalumnae: Functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods.
To investigate the morphology and evolutionary origin of muscles in vertebrate limbs, we conducted anatomical dissections, computed tomography and kinematic analyses on the pectoral fin of the African coelacanth, Latimeria chalumnae. We discovered nine antagonistic pairs of pronators and supinators that are anatomically and functionally distinct from the abductor and adductor superficiales and profundi. In particular, the first pronator and supinator pair represents mono- and biarticular muscles; a portion of the muscle fibers is attached to ridges on the humerus and is separated into two monoarticular muscles, whereas, as a biarticular muscle, the main body is inserted into the radius by crossing two joints from the shoulder girdle. This pair, consisting of a pronator and supinator, constitutes a muscle arrangement equivalent to two human antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod between the shoulder and elbow joints. Our recent kinesiological and biomechanical engineering studies on human limbs have demonstrated that two antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod (1) coordinately control output force and force direction at the wrist and ankle and (2) achieve a contact task to carry out weight-bearing motion and maintain stable posture. Therefore, along with dissections of the pectoral fins in two lungfish species, Neoceratodus forsteri and Protopterus aethiopicus, we discuss the functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods. Anat Rec, 299:1203-1223, 2016. © 2016 Wiley Periodicals, Inc.
Topics: Animal Fins; Animals; Biological Evolution; Biomechanical Phenomena; Fishes; Fossils; Pectoralis Muscles; Phylogeny; Tomography, X-Ray Computed
PubMed: 27343022
DOI: 10.1002/ar.23392 -
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 -
Journal of Anatomy Feb 2018In the last decades, Danio rerio became one of the most used model organisms in various evo-devo studies devoted to the fin skeletal anatomy and fin-limb transition....
In the last decades, Danio rerio became one of the most used model organisms in various evo-devo studies devoted to the fin skeletal anatomy and fin-limb transition. Surprisingly, there is not even a single paper about the detailed anatomy of the adult muscles of the five fin types of this species. To facilitate more integrative developmental, functional, genetic, and evolutionary studies of the appendicular musculoskeletal system of the zebrafish and to provide a basis for further comparisons with other fishes and tetrapods, we describe here the identity, overall configuration, and attachments of appendicular muscles in a way that can be easily understood and implemented by non-anatomist researchers. We show that the muscle pattern of the caudal fin is very different from patterns seen in other fins but is very consistent within teleosts. Our observations support the idea of the developmental and evolutionary distinction of the caudal fin and point out that the musculature of the adult zebrafish pectoral and pelvic fins is in general very similar. Both paired fins have superficial and deep layers of abductors and adductors going to all/most rays plus the dorsal and ventral arrectors going only to the first ray. Nevertheless, we noted three major differences between the pelvic and pectoral fins of adult zebrafishes: (i) the pectoral girdle lacks a retractor muscle, which is present in the pelvic girdle - the retractor ischii; (ii) the protractor of the pelvic girdle is an appendicular/trunk muscle, while that of the pectoral girdle is a branchiomeric muscle; (iii) the first ray of the pectoral fin is moved by an additional arrector-3. The anal and dorsal fins consist of serially repeated units, each of which comprises one half-ray and three appendicular muscles (one erector, depressor, and inclinator) on each side of the body. The outermost rays are attachment points for the longitudinal protractor and retractor. Based on our results, we discuss whether the pectoral appendage might evolutionarily be closer to the head than to the pelvic appendage and whether the pelvic appendage might have been derived from the trunk/median fins. We discuss a hypothesis of paired fin origin that is a hybrid of the fin-fold and Gegenbaur's theories. Lastly, our data indicate that D. rerio is indeed an appropriate model organism for the appendicular musculature of teleosts in particular and, at least in the case of the paired fins, also of actinopterygians as a whole.
Topics: Anatomy, Comparative; Animal Fins; Animals; Biological Evolution; Muscle, Skeletal; Zebrafish
PubMed: 29148042
DOI: 10.1111/joa.12728