Riojasaurus is a prehistoric reptile that lived during the Late Triassic period around 225 million years ago. As a member of the sauropod family, this dinosaur was known for its long neck and tail, and large size. While there are no true synonyms for the word "riojasaurus," there are related terms that refer to other dinosaurs in the same family, as well as other herbivorous creatures. These include titanosaur, apatosaur, diplodocus, and brachiosaur. Learning about these different dinosaur species can help provide a deeper understanding of the diversity and complexity of the natural world throughout history.