UNUSUAL PRESERVATION OF THE PELVIC REGION OF PLATECARPUS, (MOSASAURIDAE; REPTILIA) FROM THE SHARON SPRINGS MEMBER OF THE PIERRE SHALE

A specimen of Platecarpus sp. was collected from the Sharon Springs Member of the Pierre Shale in Lyman County, South Dakota during the summers of 2001-2003. Upon removal the specimen was discovered to have an articulated vertebral column beginning with the posterior dorsal vertebrae and ending with terminal caudal vertebrae, encompassing hind limb and pelvic elements. Detailed investigation has focused on the well-preserved rear paddles and pelvic structures. The right hind limb is well articulated, while the left is slightly disarticulated but equally well preserved. The right portion of the pelvic structure is doubled underneath the articulated left portion and is slightly more disarticulated. This specimen provides valuable information concerning the structure and function of the hind limbs and pelvic region of Platecarpus, providing additional insight into the musculature of the posterior region of Platecarpus.