Update: Bad news. Michel Raynal tells me this book is not new. It was first brought out in 1984 and is half fiction. Okay. Nevermind. It goes in the cryptofiction pile.
If you can read French, you will enjoy a new book by Christian Dedet, about giant reptiles seen near or in the Gabon River, Africa. The book is The Memory of the River, about the life of Jean Michonet. Near the beginning of the book is a passage on the extraordinary fight between a giant snake and a large elephant that took place near the St. Anne Catholic mission in Gabon.
The book contains another incredible meeting with “a giant snake,” worthy of the one described in the memoirs of Colonel Fawcett.
There is also an entire chapter on snakes, specifically talking of giant cryptid snakes.
One section notes (rough Google translation):
The giant snake – the same one that failed to end my youthful adventure on a tributary of Rainbo N’Komi – has a jaw so flexible, so expandable that it allows the snake to swallow a buffalo. We can meet specimens reaching almost 20 meters. The one that fought against an elephant, once in the lagoons of St. Anne, was probably of this size. There is not too long ago, a small zoo in Zaire, where I was shown a 19-meter specimen. My father said he saw pythons measuring up to 12 meters. Source.