. Differential growth in three ichthyosaurs : Ichthyosaurus communis, I. breviceps, and Stenopterygius quadriscissus (Reptilia, Ichthyosauria). Ichthyosauria. vertical component. vertical component Fig. 9 Diagrams of an ichthyosaur tail showing how the downthrust produced by the epicaudal lobe can be resolved into vertical and horizontal components. A. Angle of tail bend is small, b. Angle is larger and the vertical component is correspondingly decreased. system are two more inclined planes resulting from deflections of the epicaudal and hypocaudal lobes, particularly towards their tips which
. Differential growth in three ichthyosaurs : Ichthyosaurus communis, I. breviceps, and Stenopterygius quadriscissus (Reptilia, Ichthyosauria). Ichthyosauria. vertical component. vertical component Fig. 9 Diagrams of an ichthyosaur tail showing how the downthrust produced by the epicaudal lobe can be resolved into vertical and horizontal components. A. Angle of tail bend is small, b. Angle is larger and the vertical component is correspondingly decreased. system are two more inclined planes resulting from deflections of the epicaudal and hypocaudal lobes, particularly towards their tips which are more flexible (Fig. 8e). The epicaudal lobe moves at an obtuse angle of attack (Fig. 8e: a°) to the direction of motion of the tail giving a down- thrust, which is compensated for by the upthrust given by the hypocaudal lobe moving at an acute angle of attack (Fig. 8e: b°) to the direction of motion. In the ichthyosaur, which had a reversed heterocercal tail, the hypocaudal lobe of the tail was more rigid than the epicaudal lobe because of the support afforded by the downturned vertebral column. Thus when the tail was moved from side to side, the epicaudal lobe was deflected more than the hypocaudal lobe (Fig. 8f), producing a greater thrust (down- id. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original McGowan, Christopher. Toronto : Royal Ontario Museum
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Keywords: ., bookcentury1900, bookleafnumber20, booksponsorunive, bookyear1973
