Multibody dynamics model of head and neck function in Allosaurus (Dinosauria, Theropoda)

Abstract

We present a multibody dynamics model of the feeding apparatus of the large Jurassic theropod dinosaur Allosaurus that enables testing of hypotheses about the animal's feeding behavior and about how anatomical parameters influence function. We created CT-and anatomical-inference-based models of bone, soft tissue, and air spaces which we use to provide inertial properties for musculoskeletal dynamics. Estimates of bone density have a surprisingly large effect on head inertial properties, and trachea diameter strongly affects moments of inertia of neck segments for dorsoventral movements. The ventrally-placed insertion of m. longissimus capitis superficialis in Allosaurus imparted over twice the ventroflexive accelerations of a proxy control insertion lateral to the occipital condyle, the latter being its position in nearly all other theropods. A feeding style that involved defleshing a carcass by avian-raptor-like retraction of the head in Allosaurus is more probable than is lateroflexive shake-feeding, such as that seen in crocodilians and inferred for tyrannosaurids.

Vascular Patterns in the Heads of Dinosaurs: Evidence for Blood Vessels, Sites of Thermal Exchange, and Their Role in Physiological Thermoregulatory Strategies

“…Moreover, the cephalic blood vessels are supplying the head, not the body, and so head volume is a biologically relevant size metric, particularly given that species with similar body masses may have drastically different head shapes and sizes. Head volume (Table ) was measured by segmenting CT data and wrapping the skull in a “skin” (the outer surface envelope of the head) and then subtracting the estimated volumes of the nasal and oral air spaces (Witmer and Ridgely, ; Snively et al, ). Diapsid 3D models (Porter and Witmer, , ; Porter et al, ) made in Maya (Autodesk, San Rafael, CA) were used to visualize blood vessels.…”

The role of the neck in the feeding behaviour of the Tyrannosauridae: inference based on kinematics and muscle function of extant avians

“…The ability of tyrannosaurids to fragment the bones of prey is well documented (Erickson & Olsen, 1996;Chin et al, 1998Chin et al, , 2003, and was achieved by force generated by large jaw adductors (Molnar, 1973;Bates & Falkingham, 2012). There is no evidence for specialized head ventroflexion as present in Allosaurus (Rayfield et al, 2001), which had a ventroflexive moment arm for head lateroflexors (Bakker, 2000;Snively et al, 2013) as well as for normal cranial ventroflexors (including M. longissimus capitis profundus). Unlike raptorial birds, which puncture large prey with the talons (Fowler et al, 2009) and impale it with the tip of the beak to secure food in the jaws, tyrannosaurids would have perforated the prey as much as necessary with the tooth rows, and for Stage 5 tore 'along the dotted line' and excised flesh trapped posterior to the teeth, as do varanids (Auffenberg, 1978).…”

Coupling finite element analysis and multibody system dynamics for biological research

“…It is important to differentiate the FMSD, which couples the equations of the MSD and the FEA during the simulation from the other excellent approaches that can be found in the literature. Firstly, in Curtis et al (2009Curtis et al ( , 2010a, Bates and Falkingham (2012) and Snively et al (2013) only the MSD equations are used to determine the forces that are acting in the model without any interaction with FEA and secondly, in Moazen et al (2008a) and Curtis et al (2011) there is a combination between MSD and FEA but they are not coupled during the simulation. Uncoupled analysis does not account for strains being a result of dynamics response of a flexible object.…”

“…The technique has been applied to studies of craniofacial form to simulate musculoskeletal function and facilitates in-depth exploration of the relationships between musculoskeletal geometry, muscle parameters, forces and motion in vertebrate structures (Curtis et al, 2009;Bates and Falkingham, 2012;Gröning et al, 2013;Snively et al, 2013). In spite of it, the research utilizing both the musculoskeletal modeling and deformable body modeling together has rarely been seen in publications (Moazen et al, 2008a(Moazen et al, , 2008bCurtis, 2011;Curtis et al, 2010aCurtis et al, , 2010bCurtis et al, , 2011.…”