|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1994 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1993 : ¥900,000 (Direct Cost : ¥900,000)
Desmostylians have abducted stylopodia like a reptile with joints of mammalian type. The purpose of the present study is to restore how they actually walked. The study includes two kinds of approaches. First, various types of walking in living mammals were taken pictures by a video camera. The video was displayd in every one-sixties seconds. The pictures on the monitor were taken by a motordrived camera in every one-sixtieth, one-thirtieth or one-twentieth corresponding to the walking speed. A series of the pictures were divided on the phase of foot contact or foot off, and were classified to some gaits based on the support formula. As a result of this research, six types of gait are obtaines. The correlation among the gait cycle, the rhythm of limb work, the rhythm of locomotion and hind limb ratio in each gait and each mammal is researched. In four types of limb posture of mammals, pseudounguligrade, unguligrade, digitigrade and plantigrade, change of angles in every 0.1 second at four joints, elbow, wrist, knee and ankle, are measured and compared with each animal or joint.
On the other hand, a skeletal model of Desmostylus with movable joints was mounted. Universal joints are used for the shoulder and hip joints, hinge joints for the elbow, wrist and ankle joints, and a kind of trochoid joint for the complex wrist joint so that each joint can move like a real joint. Using this model, both limbs proved to be movable as the foot toes reciprocate sagittally with forward pointed toe tips. In conclusion, the desmostylian has symmetrical diagonal gait and seems to walk with a gait of very slow diagonal walk.Usually the gait changes via slow racklike walk to normal walk, as an animal speeds up.