It is uncertain whether the Parasaurolophus had vocal cords. Therefore, a variation of sounds with and without vocal cords have been simulated for this organism. This group of vertebrates is the first to achieve true flight . The University of California Museum of Paleontology offers information on Mesozoic terrestrial ecology . The sea crocodile is the only group evolved into marine habitat.
Crocodiles are Extant.
The presently accepted hypothesis of bird origins state that they evolved from small Triassic bipedal theropods . Within the past several years, a newly described fossil Sinosauropteryx prima , has provided information that initially would seem to affect the debate over the origin of birds. After examination, though, it was determined that this animal did not possess feathers. But, new fossil material described in 1998 by a multi-national team have demonstrated that feathers are not just for birds any more. These new specimens demonstrate that dinosaurs had feathers, too.