Shunosaurus was first estimated to be 11 metres (36 ft) long; later and more complete finds indicated a somewhat smaller size. In 2010 Gregory S. Paul estimated the length at 9.5 metres (31 ft), the weight at 3 metric tons (3.3 short tons). Shunosaurus was very short-necked for a sauropod, being only "surpassed" in this respect by Brachytrachelopan. The skulls found are mostly compressed or disarticulated and the interpretation of the head form has varied from broad, short and deep to extremely narrow and pointed. The upper and lower jaws were strongly curved upwards, allowing them to function as a pair of garden shears. The teeth were fairly robust but elongated with a crown length of up to 8 centimetres (3.1 in). They show a unique combination of a cylindrical body ending in a spatulate tip. In 1989 it was disclosed that the tail ended in a club, equipped on its top with two successive spikes formed by 5 centimetres (2.0 in)-long cone-shaped osteoderms probably used to fend off enemies.