scholarly journals Maniraptoran pelvic musculature highlights evolutionary patterns in theropod locomotion on the line to birds

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10855
Author(s):  
Matthew M. Rhodes ◽  
Donald M. Henderson ◽  
Philip J. Currie
Keyword(s):  
Hind Limb ◽  
Soft Tissues ◽  
Morphological Features ◽  
Fundamental Aspect ◽  
Evolutionary Patterns ◽  
Theropod Dinosaurs ◽  
Relative Differences ◽  
Insight Into

Locomotion is a fundamental aspect of palaeobiology and often investigated by comparing osteological structures and proportions. Previous studies document a stepwise accumulation of avian-like features in theropod dinosaurs that accelerates in the clade Maniraptora. However, the soft tissues that influenced the skeleton offer another perspective on locomotory adaptations. Examination of the pelvis for osteological correlates of hind limb and tail musculature allowed reconstruction of primary locomotory muscles across theropods and their closest extant relatives. Additionally, the areas of pelvic muscle origins were quantified to measure relative differences within and between taxa, to compare morphological features associated with cursoriality, and offer insight into the evolution of locomotor modules. Locomotory inferences based on myology often corroborate those based on osteology, although they occasionally conflict and indicate greater complexity than previously appreciated. Maniraptoran pelvic musculature underscores previous studies noting the multifaceted nature of cursoriality and suggests that a more punctuated step in caudal decoupling occurred at or near the base of Maniraptora.

Caudofemoral musculature and the evolution of theropod locomotion

Paleobiology ◽  
1990 ◽  
Vol 16 (2) ◽  
pp. 170-186 ◽  
Author(s):  
Stephen M. Gatesy
Keyword(s):  
Knee Flexion ◽  
Hind Limb ◽  
The Body ◽  
Avian Evolution ◽  
Theropod Dinosaurs ◽  
Data Support ◽  
Caudal Vertebrae ◽  
Longus Muscle

Living crocodilians and limbed lepidosaurs have a large caudofemoralis longus muscle passing from tail to femur. Anatomical and electromyographic data support the conclusion that the caudofemoralis is the principal femoral retractor and thus serves as the primary propulsive muscle of the hind limb. Osteological evidence of both origin and insertion indicates that a substantial caudofemoralis longus was present in archosaurs primitively and was retained in the clades Dinosauria and Theropoda. Derived theropods (e.g., ornithomimids, deinonychosaurs, Archaeopteryx and birds) exhibit features that indicate a reduction in caudofemoral musculature, including fewer caudal vertebrae, diminished caudal transverse processes, distal specialization of the tail, and loss of the fourth trochanter. This trend culminates in ornithurine birds, which have greatly reduced tails and either have a minute caudofemoralis longus or lack the muscle entirely.As derived theropod dinosaurs, birds represent the best living model for reconstructing extinct nonavian theropods. Bipedal, digitigrade locomotion on fully erect limbs is an avian feature inherited from theropod ancestors. However, the primitive saurian mechanisms of balancing the body (with a large tail) and retracting the limb (with the caudofemoralis longus) were abandoned in the course of avian evolution. This strongly suggests that details of the orientation (subhorizontal femur) and movement (primarily knee flexion) of the hind limb in extant birds are more properly viewed as derived, uniquely avian conditions, rather than as retentions of an ancestral dinosaurian pattern. Although many characters often associated with extant birds appeared much earlier in theropod evolution, reconstructing the locomotion of all theropods as completely birdlike ignores a wealth of differences that characterize birds.

scholarly journals Occlusion Effect in Response to Stimulation by Soft Tissue Conduction-Implications

2020 ◽  
Vol 10 (2) ◽  
pp. 69-76
Author(s):  
Miriam Geal-Dor ◽  
Cahtia Adelman ◽  
Shai Chordekar ◽  
Haim Sohmer
Keyword(s):  
Blood Flow ◽  
Soft Tissue ◽  
Inner Ear ◽  
Statistical Difference ◽  
Soft Tissues ◽  
Bone Conduction ◽  
External Canal ◽  
Pure Tones ◽  
Occlusion Effect ◽  
Insight Into

To gain insight into the broader implications of the occlusion effect (OE—difference between unoccluded and occluded external canal thresholds), the OE in response to pure tones at 0.5, 1.0, 2.0 and 4.0 kHz to two bone conduction sites (mastoid and forehead) and two soft tissue conduction (STC) sites (under the chin and at the neck) were assessed. The OE was present at the soft tissue sites and at the bone conduction sites, with no statistical difference between them. The OE was significantly greater at lower frequencies, and negligible at higher frequencies. It seems that the vibrations induced in the soft tissues (STC) during stimulation at the soft tissue sites are conducted not only to the inner ear and elicit hearing, but also reach the walls of the external canal and initiate air pressures in the occluded canal which drive the tympanic membrane and excite the inner ear, leading to hearing. Use of a stethoscope by the internist to hear intrinsic body sounds (heartbeat, blood flow) serves as a clear demonstration of STC and its relation to hearing.

scholarly journals Hind limb myology of the southern brown bandicoot (Isoodon obesulus) and greater bilby (Macrotis lagotis) (Marsupialia : Peramelemorphia)

2015 ◽  
Vol 63 (3) ◽  
pp. 147 ◽  
Author(s):  
Natalie M. Warburton ◽  
Auréline Malric ◽  
Maud Yakovleff ◽  
Veronique Leonard ◽  
Charlotte Cailleau
Keyword(s):  
Hind Limb ◽  
New Guinea ◽  
Morphological Features ◽  
Significant Modification ◽  
Connective Tissues ◽  
Environmental Pressures ◽  
Unusual Combination ◽  
Tibiofibular Joint

Bandicoots and bilbies (order Peramelemorphia) represent the principal group of omnivorous marsupials from a range of habitats across Australia and New Guinea. Bandicoots and bilbies most commonly use quadrupedal, asymmetrical half-bounding or bounding gaits and present an unusual combination of hind limb morphological features, including an ossified patella, a modified tibiofibular joint, and syndactylous morphology of the pes. We performed comparative dissections of the hind limb of the southern brown bandicoot (Isoodon obesulus fusciventer) (n = 13) and greater bilby (Macrotis lagotis) (n = 4), providing detailed descriptions of the muscular anatomy. These species displayed significant modification of the hind limb muscular anatomy and associated connective tissues, including emphasis on multiarticular muscles, such as the hamstrings, and extreme development of fascial structures. These patterns were more extreme in I. obesulus than in M. lagotis. Differences between the hind limb anatomy of I. obesulus and M. lagotis reflect the different ecological and environmental pressures on their locomotion and digging behaviours.

scholarly journals Renitence vacuoles facilitate protection against phagolysosomal damage in activated macrophages

2018 ◽  
Vol 29 (5) ◽  
pp. 657-668 ◽  
Author(s):  
Amanda O. Wong ◽  
Matangi Marthi ◽  
Zachary I. Mendel ◽  
Brian Gregorka ◽  
Michele S. Swanson ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Morphological Features ◽  
Activated Macrophages ◽  
Membrane Ruffling ◽  
Silica Bead ◽  
Mechanistic Insight ◽  
Silica Beads ◽  
Lps Activation ◽  
Kinetics Of ◽  
Insight Into

As professional phagocytes, macrophages are susceptible to endolysosomal membrane damage inflicted by the pathogens and noxious particles they ingest. Whether macrophages have mechanisms for limiting such damage is not well understood. Previously, we reported a phenomenon, termed “inducible renitence,” in which lipopolysaccharide (LPS) activation of macrophages protected their endolysosomes against damage initiated by the phagocytosis of silica beads. To gain mechanistic insight into the process, we analyzed the kinetics of renitence and morphological features of LPS-activated versus resting macrophages following silica bead–mediated injury. We discovered novel vacuolar structures that form in LPS-activated but not resting macrophages following silica bead phagocytosis. Because of their correlation with renitence and damage-resistant nature, we termed these structures “renitence vacuoles” (RVs). RVs formed coincident with silica bead uptake in a process associated with membrane ruffling and macropinocytosis. However, unlike normal macropinosomes (MPs), which shrink within 20 min of formation, RVs persisted around bead-containing phagosomes. RVs fused with lysosomes, whereas associated phagosomes typically did not. These findings are consistent with a model in which RVs, as persistent MPs, prevent fusion between damaged phagosomes and intact lysosomes and thereby preserve endolysosomal integrity.

Finite Element Implementation of a Planar Soft Tissue Structural Constitutive Model for Heart Valve Simulations

2013 ◽  
Author(s):  
Rong Fan ◽  
Michael S. Sacks
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Soft Tissues ◽  
Structural Model ◽  
Mechanical Response ◽  
Biological Tissues ◽  
Biaxial Test ◽  
Tissue Microstructure ◽  
Highly Nonlinear ◽  
Insight Into

Constitutive modeling is critical for numerical simulation and analysis of soft biological tissues. The highly nonlinear and anisotropic mechanical behaviors of soft tissues are typically due to the interaction of tissue microstructure. By incorporating information of fiber orientation and distribution at tissue microscopic scale, the structural model avoids ambiguities in material characterization. Moreover, structural models produce much more information than just simple stress-strain results, but can provide much insight into how soft tissues internally reorganize to external loads by adjusting their internal microstructure. It is only through simulation of an entire organ system can such information be derived and provide insight into physiological function. However, accurate implementation and rigorous validation of these models remains very limited. In the present study we implemented a structural constitutive model into a commercial finite element package for planar soft tissues. The structural model was applied to simulate strip biaxial test for native bovine pericardium, and a single pulmonary valve leaflet deformation. In addition to prediction of the mechanical response, we demonstrate how a structural model can provide deeper insights into fiber deformation fiber reorientation and fiber recruitment.

scholarly journals The biostratigraphy of the Upper Pliensbachian-Toarcian (Lower Jurassic) sequence at Ilminster, Somerset

2009 ◽  
Vol 28 (1) ◽  
pp. 67-85 ◽  
Author(s):  
I. Boomer ◽  
A. R. Lord ◽  
K. N. Page ◽  
P. R. Bown ◽  
F. M. D. Lowry ◽  
...  
Keyword(s):  
Lower Jurassic ◽  
Calcareous Nannofossils ◽  
Marked Contrast ◽  
Evolutionary Patterns ◽  
Southern England ◽  
Carbonate Deposit ◽  
Temporary Road ◽  
Insight Into ◽  
Jurassic Sequence

Abstract. Temporary road sections for the A303 bypass at Ilminster, Somerset, revealed Upper Pliensbachian and Toarcian sediments from an alternating limestone–marl facies, in marked contrast to the limestone-dominated Dorset coast succession. The lithostratigraphy is described, with the standard ammonite zonation providing chronostratigraphical correlation. The uppermost Pliensbachian (Spinatum Chronozone) and much of the Toarcian (Serpentinum, Bifrons, Variabilis, Thouarsense and Pseudoradiosa chronozones) of the classic Dorset coast Lower Jurassic sequence are represented by the Beacon Limestone Formation, formerly the ‘Junction Bed’ (a highly condensed carbonate deposit). The Tenuicostatum Chronozone is largely missing from the sequence. Elsewhere in southern and eastern England this interval is poorly or rarely exposed. The argillaceous units have yielded rich microfaunas and -floras (foraminifera, ostracods, calcareous nannofossils and palynomorphs), the biostratigraphical distributions of which are analysed and discussed in relation to contemporary evolutionary patterns and other UK records. This study provides an insight into the micro-biostratigraphy of the Late Pliensbachian to Toarcian interval for onshore southern England.

scholarly journals The anomaly P syndrome in green frogs: the history of discovery, morphological features and possible causes

2020 ◽  
Vol 324 (1) ◽  
pp. 108-123
Author(s):  
A.O. Svinin ◽  
O.A. Ermakov ◽  
S.N. Litvinchuk ◽  
I.V. Bashinskiy
Keyword(s):  
Hind Limb ◽  
Infectious Agent ◽  
Morphological Features ◽  
Intermediate Hosts ◽  
Amphibian Species ◽  
Mandibular Hypoplasia ◽  
Hind Limbs ◽  
Western Palearctic ◽  
Morphological Transformations ◽  
Limb Flexion

The anomaly P in green frogs was firstly found in 1952 in France by French writer and scientist Jean Rostand. Mild form of anomaly P manifestation includes polydactyly, while complex morphological transformations affect the fore and hindlimbs and include combinations of traits: polydactyly, brachymely, hind limb flexion, small additional limbs, bone outgrowths, tumors and edema in the hind limbs. Rostand experimentally showed that this anomaly is not inherited and is caused by some environmental factors. It was recorded only in Western Palearctic green frogs of the genus Pelophylax and was absent in other amphibian species, despite their syntopic occurrence. The severe cases of anomaly P were not found for a long time by researchers and were re-discovered after half a century since its last observation. A new record was made in 2016 in the central part of Russia in the Privolzhskaya Lesostep’ nature reserve. The morphological features of the anomalous frogs in the study area turned out to be similar to those described by Rostand. Symmetric polydactyly, brachymely, hind limb flexion, edema of hind limbs, small additional limbs in thighs, outgrowths, and concomitant anomalies – mandibular hypoplasia, unmoved hind limb, open opercular chamber. The frequency of occurrence of the anomaly in the studied population reached 24.7% (n = 384). Moreover, the “severe forms” of the anomaly P were noted in 4.7% of cases, and the “light” (polydactyly) in 20.0%. Growing tadpoles together with freshwater mollusks allowed us to obtain the anomaly P in the laboratory. It was revealed that the mollusks Planorbarius corneus are the intermediate hosts (vectors) for the “infectious agent” of this anomaly. As the most possible cause of the anomaly, the infection by trematodes species is considered.

Implementation and Validation of Planar Soft Tissue Structural Constitutive Model

2013 ◽  
Author(s):  
Rong Fan ◽  
Michael S. Sacks
Keyword(s):  
Constitutive Model ◽  
Soft Tissues ◽  
Structural Model ◽  
Mechanical Response ◽  
Biological Tissues ◽  
Fetal Membrane ◽  
Tissue Microstructure ◽  
Highly Nonlinear ◽  
Finite Element Package ◽  
Insight Into

Constitutive modeling is of fundamental important for numerical simulation and analysis of soft biological tissues. The mechanical behaviors of soft tissues are usually highly nonlinear and anisotropic. The complex behavior is the results from the interaction of tissue microstructure. By incorporating information of fiber orientation and distribution at tissue microscopic scale, the structural model avoids ambiguities in material characterization. Moreover, structural models produce much more information than just simple stress-strain results, but can provide much insight into how soft tissues internally reorganize to external loads by adjusting their internal microstructure. Moreover, it is only through simulation of an entire organ system can such information be derived and provide insight into physiological function. However, accurate implementation and rigorous validation of these models remains very limited. In the present study we implemented a structural constitutive model into a commercial finite element package. The structural model was verified against experiential test data for native bovine pericardium and fetal membrane. In addition to prediction of the mechanical response, we demonstrate how a structural model can provide deeper insights into fiber reorientation and fiber recruitment.

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