Sauropoda - History of Discovery

History of Discovery

The first scrappy fossil remains now recognized as sauropods all came from England and were originally interpreted in a variety of different ways. Their relationship to other dinosaurs was not recognized until well after their initial discovery.

The first sauropod fossil to be scientifically described was a single tooth known by the non-Linnaean descriptor Rutellum implicatum. This fossil was described by Edward Lhuyd in 1699, but was not recognized as a giant prehistoric reptile at the time. Dinosaurs would not be recognized as a group until over a century later.

Richard Owen published the first modern scientific description of sauropods in 1841, in his paper naming Cetiosaurus and Cardiodon. Cardiodon was known only from a two unusual, heart-shaped teeth (from which it got its name), which could not be identified beyond the fact that they came from a previously unknown large reptile. Cetiosaurus was known from slightly better, but still scrappy remains. Owen thought at the time that Cetiosaurus was a giant marine reptile related to modern crocodiles, hence its name, which means "whale lizard". A year later, when Owen coined the name Dinosauria, he did not include Cetiosaurus and Cardiodon in that group.

In 1850, Gideon Mantell recognized the dinosaurian nature of several bones assigned to Cetiosaurus by Owen. Mantell noticed that the leg bones contained a medullary cavity, a characteristic of land animals. He assigned these specimens to the new genus Pelorosaurus, and grouped it together with the dinosaurs. However, Mantell still did not recognize the relationship to Cetiosaurus.

The next sauropod find to be described and misidentified as something other than a dinosaur were a set of hip vertebrae described by Harry Seeley in 1870. Seeley found that the vertebrae were very lightly constructed for their size and contained openings for air sacs (pneumatization). Such air sacs were at the time known only in birds and pterosaurs, and Seeley considered the vertebrae to come from a pterosaur. He named the new genus Ornithopsis, or "bird face" because of this.

When more complete specimens of Cetiosaurus were described by Phillips in 1871, he finally recognized the animal as a dinosaur related to Pelorosaurus. However, it was not until the description of new, nearly complete sauropod skeletons from the United States (representing Apatosaurus and Camarasaurus) later that year that a complete picture of sauropods emerged. An approximate reconstruction of a complete sauropod skeleton was produced by John A. Ryder, based on the remains of Camarasaurus, though many features were still inaccurate or incomplete according to later finds and biomechanical studies. Also in 1877, Richard Lydekker named another relative of Cetiosaurus, Titanosaurus, based on an isolated vertebra.

In 1878, the most complete sauropod yet was found and described by Othniel Charles Marsh, who named it Diplodocus. With this find, Marsh also created a new group to contain Diplodocus, Cetiosaurus, and their increasing roster of relatives to differentiate them from the other major groups of dinosaurs. Marsh named this group Sauropoda, or "lizard feet".