A team of scientists has discovered an exceptional specimen of titanosaur in Tanzania. This sauropod dinosaur, which describes in the journal PLOS ONE, represents a unique species and provides new knowledge on the evolution of these vertebrates.
The titanosaurs were the largest group of dinosaurs, the largest terrestrial animals that have trodden the Earth. They reached their maximum diversity in the Late Cretaceous after all the other groups of sauropods disappeared. However, its early evolution is little known due to the scarcity of well preserved fossils, especially outside of South America. Hence the importance of this new copy.
«Although the titanosaurs became one of the most successful dinosaur groups before the mass extinction, its primitive evolutionary history remains obscure. Mnyamawamtuka helps to detail those beginnings, especially for the African part of history, "emphasizes Eric Gorscak, a researcher at Midwestern University in Illinois (USA), who along with Patrick O'Connor of the University of Ohio (USA) Lead the work.
The researchers called the new dinosaur Mnyamawamtuka moyowamkia. Its description has been made only from a specimen excavated in a quarry along the Mtuka River, in southwestern Tanzania. But it is one of the most complete known specimens, especially from Africa.
A tyrannosaurus with heart-shaped vertebrae
Mnyamawamtuka retains partial remains of each important body region, including numerous vertebrae, ribs, limb bones and teeth. Its scientific name derives from the kishwahili (Swahili) and means "beast of Mtuka" and "heart of the tail", referring respectively to the location where it was found and to the center of the vertebrae of its tail that have the shape of a heart.
When comparing Mnyamawamtuka with the known family tree of the titanosaurs, the researchers concluded that this new species it fits near the origin of a clade called Lithostrotia, which includes the majority of the titanosaur species of the Upper Cretaceous. This dinosaur represents, therefore, an early stage in the evolution of titanosaurs.
The discovery adds to the evidence of a close relationship between the titanosaurs of South Africa and South America, a link that was probably important in the evolution of Cretaceous ecosystems in the southern continents, according to the study.