Like other ankylosaurs, Sauropelta had a wide body, with a very broad pelvis and ribcage. The forelimbs were shorter than the hindlimbs, which resulted in an arched back, with the highest point over the hips. Its feet, limbs, shoulders, and pelvis were all very stoutly constructed and reinforced to support a great deal of weight. Like other nodosaurids, Sauropelta was covered in armor formed from bony masses embedded in the skin (osteoderms). The discovery of a skeleton with the body armor preserved in situ allowed Carpenter and other scientists to accurately describe this protection. Two parallel rows of domed scutes ran down the top of the neck, along the anteroposterior axis (front to back). On the upper surface of the back and tail, the skin was covered in small, bony nodules (ossicles), which separated larger conical scutes arranged in parallel rows along the mediolateral axis (side to side). Over the hips, the ossicles and larger domed plates were interlocked very tightly to form a structure called a sacral shield. This shield is also found in ankylosaurs like Polacanthus and Antarctopelta. Large, pointed spines lined the sides of the neck, increasing in size towards the shoulders, and then decreasing in size again along the side of the body until they stopped just before the hips. Behind the hips, flat triangular plates lined the tail on both sides, pointing laterally (outwards) and decreasing in size towards the end of the tail. Carpenter originally described the cervical (neck) spines and caudal plates as belonging to a single row on each side, although more recently he and Jim Kirkland reconstructed them in two parallel rows on each side, one above the other. The upper row of cervical spines pointed backwards and upwards (posterodorsally), while the lower row pointed backwards and outwards (posterolaterally). The bases of each pair of cervical spines and each pair of caudal plates were fused together, greatly restricting mobility in both the neck and upper tail. Classification and systematics Since John Ostrom first described Sauropelta in 1970, it has been recognized as a member of the family Nodosauridae. The nodosaurids, along with the family Ankylosauridae, belong within the infraorder Ankylosauria. Nodosaurids are characterized by certain features of the skull, including the mandible (lower jaw), which curves downwards at the end. Overall, nodosaurids had narrower snouts than the ankylosaurids, and also lacked the heavy ankylosaurid tail clubs. Nodosaurids, like ankylosaurids, are found