Sauropod skulls are rare. As big as impressive as these long-necked giants were, they often lost their heads after death. There were decades of confusion over what the skull of Apatosaurus looked like. This makes the discovery of any complete sauropod skull cause for celebration, and I was delighted to hear that an international team of paleontologists has just described the noggin of a previously unknown sauropod from Brazil.
Described in PLoS One, the new dinosaur is named Tapuiasaurus macedoi. A member of the sauropod subgroup called
But Tapuiasaurus lived long before these dinosaurs. Even though Rapetosaurus and Nemegtosaurus were found to be the closest known relatives of the new dinosaur, they lived about 30 million years after Tapuiasaurus. In terms of evolutionary history, this means that the skull shape of the Late Cretaceous titanosaurs evolved much earlier than was previously thought, and there are probably many other related dinosaurs yet to be found in the gap between Tapuiasaurus and its later cousins. With any luck, more skulls will turn up to fill out the evolutionary history of these dinosaurs.
Zaher, H., Pol, D., Carvalho, A., Nascimento, P., Riccomini, C., Larson, P., Juarez-Valieri, R., Pires-Domingues, R., da Silva, N., & de Almeida Campos, D. (2011). A Complete Skull of an Early Cretaceous Sauropod and the Evolution of Advanced Titanosaurians PLoS ONE, 6 (2) DOI: 10.1371/journal.pone.0016663