Titanosaur

Head and neck

Titanosaur necks were of average length for sauropods, and their tails were whip-like though not as long as in the diplodocids. While the pelvis was slimmer than some sauropods, the pectoral (chest) area was much wider, giving them a uniquely "wide-legged" stance. As a result, the fossilized trackways of titanosaurs are distinctly broader than those of other sauropods. Their forelimbs were also stocky, and often longer than their hind limbs. Unlike other sauropods, some titanosaurs had no digits, walking only on horseshoe-shaped "stumps" made up of the columnar metacarpal bones. Their vertebrae (back bones) were solid (not hollowed-out), which may be a reversal to more basal saurischian characteristics. Their spinal column was relatively flexible, likely making them more agile than other sauropods, though at the expense of rearing on their hind legs compared to the Diplodocoids. One of the most characteristic features shared by most titanosaurs were their procoelous caudal vertebrae, with ball-and-socket articulations between the vertebral centra.