Name means: Massive Vertebra
Species: carinatus, kaalae
Range: Late Triassic-Early Jurassic (Norian-Sinemurian, 228-191 MYA) from South Africa, Lesotho, Zimbabwe
Size estimate: 15-20 ft length, 1-1.5 tons
Discovery: Sir Richard Owen, 1854
Classification: dinosauria, saurischia, sauropodomorpha, plateosauria, massopoda
Forerunners of the sauropods, like Massospondylus, all shared the same basic body plan. Their small heads perched upon long necks. Large torsos balanced on two legs, while their arms retained the ability to grab vegetation. Together with sauropods, these animals form a group called sauropodomorphs. Older media usually call them “prosauropods,” but evidence uncovered during the last 50 years shows this was not a natural grouping. Variations in this basic “prosauropod” body plan led to a surprising variety of lifestyles. Massospondylus likely played the role of a large herbivore in its ecology. Even so, it may have included some meat in its diet. Compared to its more herbivorous relative Plateosaurus, it had a more robust skull and possibly stronger jaws. Its teeth grew in a variety of shapes and sizes, suggesting a varied diet.
Many reconstructions depict Massospondylus and other large sauropodomorphs as walking on all fours.
Early studies frequently assumed that as larger species developed, they took to a four-legged gait to support bigger bodies. However, size alone does not determine walking style. Biomechanical studies show that Massospondylus could not walk on all fours, though it may have been able to rest on its forelimbs. It could not swing its arms in an effective stride. Its arm joints were angled more for moving inward than side to side. The fossil record of early sauropodomorphs still has many holes, and the switch to the four-legged walk of later sauropods remains a mystery.