Not all legends have one origin. The chinese dragon is one of these cases. Beside the traditional Fucanglong, Yinlong and Feilong which are inspired by Confuciosaurus, komodo dragons; there are dragons like Jiaolong Quiolong and Panlong which are clearly have their origin in this freshwater sea serpent, bigger species from the oceans and crocodiles.
Jangtsenatator is already extinct during 15th or 17th century and it's remains are often sold on the black market what makes it difficult to get complete specimens. In most cases only one or two bones can be saved. Today we know about 70% of the skeleton. The genus must be very common in ancient times at the shores of the Jangtsekiang which was his original habitat, but thanks to the grand chanel it's destribution became even wider. It's possible that even Marco Polo sa this animals. On his deathbed he should have he reportedly said: "I have not told half of what I've seen".
The taxonomic position of this sea serpent is unclear is seems that it's part of an primitive group, because the front flippers shows still similarities with limbs for walking.
The some othe teeth are flat or truncated but the front teeth are mostly sharp are perfect for grapping fish which suggests a mixed diet. It's possible that the heterodont depiction chines dragons in art is based on this arrangement.