a larger medial and a smaller lateral one; the latter was located about higher than the former. These concavities received the medial and lateral condyles of the tibia, respectively. A furrow between these concavities is thought to be an attachment site for ligaments of the ankle. The much smaller calcaneus is in diameter and in maximal height. A circular element, its probable lower surface is convex, and its probable upper surface roughly textured, indicating the presence of a cartilage covering. Below the lateral condyle of the tibia, Wild noted several additional, small elements in size, which he identified as cartilage given their grainy and irregular surfaces. In contrast to bone, cartilage is seldom preserved in fossils, and in this case might have been preserved thanks to the impregnation of calcium salts. As these elements are located close to the attachment site of the Achilles tendon, the area of the ankle that experienced the highest stresses in the living animal, Wild argued that they may represent sesamoids (small structures embedded within tendons). Alternatively, they could be calcified pieces of the cartilage of the astragalus. Classification Saurischian ("reptile hipped") dinosaurs are subdivided into two major groups – the herbivorous sauropodomorphs and the mostly carnivorous theropods. Sauropodomorpha consists of the quadrupedal sauropods, which were characterized by straight, columnar limbs, as well as of a number of early and basal (early-diverging) forms that were mostly bipedal and had the limb bones angled against each other. Wild, in his 1978 description, argued that the Early Jurassic Ohmdenosaurus must have been a sauropod because its limb was clearly columnar: The tibia is more massive than seen in basal sauropodomorphs, and its upper joint surface is perpendicular to the long axis of the bone, demonstrating that the limb was straight when held in neutral posture. Furthermore, the astragalus lacks the ascending process (upwards directed bony projection) that is typical for the bipedal forms, but strongly reduced or absent in sauropods due to differences in weight distribution as a consequence of their columnar limbs. On the other hand, Wild noted a number of primitive features that are typical for basal sauropodomorphs but absent from other sauropods, including the sandal-shape of the astragalus and the stepped configuration of the lower articular surface of the tibia. The oval shape of the upper end of the tibia was intermediary between the circular shape seen in the basal sauropodomorph Plateosaurus and the