Despite the name this is not a Dinosaur but a primitive cetacean.( mistaken identity upon discovery ended up sticking with it) (whale) From about 30 million years ago. Anyways I am roughing out the shape and wanted to show you my workspace. If you look closly the artists interpretations are diferent for this so even if you are doing an existing creature you have some leeway as far as how to construct it. One pic has a dorsal fin the other does not.
Dorsal fins on whales are soft tissue so there are no remains of it. Also to make things more vague some cetaceans have dorsal fins some do not. (Orca’s and Dolphins do Humpbacks and Sperm whales do not)

I decided to make a small one. On the Basilosaurus also there are small legs in the back they are not connected to the spine. I chose thsi because of the oddnes sof it a serpentine whale with small legs in the rear.



