Exploring jungles in "deepest, darkest Africa" was a common sci-fi/fantasy trope...
...even into 1968, when this never-reprinted story appeared in Charlton Premiere #4 under the anthology banner "Unlikely Tales".
All the stories in the issue were written by up-and-comer Steve Skeates with a different artist on each tale.
This particular one was rendered by another up-and-comer Pat Boyette with the rest of the tales illustrated by vets Steve Ditko, Rocke Mastroserio, and another newcomer, Jim Aparo.
Trivia note: all the artists in this issue inked their own pencils, a rather uncommon occurence in the deadline-driven comics business where the need for speed and high-volume output tended to preclude allowing artists to do both.