Melanorosaurus

Phylogeny: Dinosauria > Saurischia > Sauropodomorpha > Plateosauria > Massopoda > Sauropodiformes > Melanorosauridae

Overview: The earliest and most basal known members of the Sauropodomorpha were all bipedal animals, while the true sauropods, such as Cetiosaurus and Diplodocus, were quadrupeds. It’s been debated when exactly the sauropodomorphs evolved four-legged locomotion, though it does often seem to coincide with larger body sizes, since four limbs could support greater weight. While not a gigantic dinosaur, Melanorosaurus was decently large by Late Triassic standards. Estimates put it at eight or more meters in length, with a weight very likely exceeding a standard ton. Unlike its earlier relatives, Melanorosaurus was fully quadrupedal. Its legs, however, weren’t the highly specialized, pillar-like limbs seen on most sauropods. Even so, its discovery in the 1920’s would prove that the sauropodomorphs were already beginning to walk quadrupedally in the Triassic.

How exactly Melanorosaurus should be classified has been debated. Some studies have found it to be a very basal sauropod, but most classify it outside the Sauropoda, within a family known as the Melanorosauridae. Camelotia, from the United Kingdom, may be a fellow member of this lineage, but not all agree with classifying it as such. Melanorosaurus was more derived than dinosaurs like Plateosaurus or Mussaurus, but less so than Lessemsaurus and its relatives (it’s currently debated if the lessemsaurids themselves were members of the Sauropoda). Melanorosaurus probably occupied a niche similar to that of true sauropods, feeding from the branches of trees and tall shrubs. Known fossils of this genus come from the lower levels of the Elliot Formation, in South Africa. The generic name of Melanorosaurus means “Black Mountain lizard”, referring to a mountain where it was found.