Optimization principles applied to the mechanism of neurocranium levation and mouth bottom depression in bony fishes (Halecostomi).

摘要: The mechanism of raising the neurocranium and lowering bottom mouth in stationary feeding bony fishes has been modelled by a four-bar linkage consisting hyoid, urohyal-sternohyoid complex, pectoral girdle neurocranium-suspensorium complex. This can be brought into locked position then prestressed epaxial hypaxial muscles. A small deviation from this position, initiated trigger muscle, causes quick-release movement chain. enables very fast dorsorotation head depression (5–50 msec). Optimal dimensions derived with regard to attuning levation movement. amplitude neurocranial maximized (e.g. Pleuronectes ) or minimized Amphisile ). An extremely large (as e.g. Chauliodus limits high kinematic transmission (an indicator for velocity acceleration neurocranium). Different mechanisms are discussed some pipefishes ( Gasterosteiformes ), flatfishes Pleuronectiformes voracious deep sea Stomiatoidei