Complex sentence: The smallest specimens were identified as "Tetragonosaurus", now seen as a synonym of "Procheneosaurus", and the largest skeletons were called either "Corythosaurus" or "Lambeosaurus"; an adult was identified as "Parasaurolophus".
Split into simpler sentences: The smallest specimens were recognized as "Tetragonosaurus" (a synonym of "Procheneosaurus"). The largest skeletons were called either "Corythosaurus" of "Lambeosaurus", with the exception of an adult being recognized as "Parasaurolophus".