Chances are much greater that that hand belonged to an amphibian. One that spent a great deal of time in the water.
6 seconds sound clip from the Creature from the Black Lagoon (1954) movie soundboard.
You can hear this line at 00:08:36.204 in the Blu-ray version of the movie.
Quote context
[...]
- Here it is, gentlemen. Exactly as I found it.
- It's amazing. It's incredible!
- Could it possibly belong to a Pleistocene man?
- Well, then how do you account for the structure of the fingers, obviously for land use?
- What do you think, Dr. Matos?
- We can be sure of one thing. Whatever it was, it was very powerful.
- You say you have hopes of finding the rest of the fossil?
- As soon as I get a suitable expedition together.
[...]