69.5 Jan. 7 Modeling a passive force channelization mechanism in batoid wing skeletons SCHAEFER, Justin*; SUMMERS, Adam; Univ. of California, Irvine; Univ. of California, Irvine email@example.com
The wing skeleton of batoid fishes (skates and rays) is composed of arrays of serially arranged skeletal elements emanating from the pectoral girdle. The joints between these skeletal elements are arranged in patterns that are specific both to the locomotor mode employed (oscillatory or undulatory) and to phylogeny. We modeled the effects of the spatial arrangement of these joints in 4 species of batoid, using the assumptions that a) joints constitute a localized point of bending, b) surrounding skeletal elements were rigid in comparison to joints, and c) muscle force acts along the line of the skeletal element proximal to the joint. Two oscillatory swimmers (Myliobatis californica, Aetobatus narinari) and two undulatory swimmers (Urobatis halleri, Dasyatis Sabina) were modeled based on radiographs. The modeled resultant force vectors varied with locomotor mode, and when interpreted in terms of the temporal and spatial variation of wave propagation between locomotor types, indicate that the joints form lines that passively dictate wing bending shape, and thus the direction of water along the wing and ultimately the direction of the thrust vector.