Tortuga, or Turtle in English, so named for the turtle carapace found a fair way back in the cave. In fact there are 2, one sitting on the sand and the second one buried with just the edges above.
Our guide, Nico, said that he knew we could easily reach them with a stage tank, but he hadnt been beyond there, so sounds like some exploration for us.
From the turtles shells the cave turns green with tanic acid in the water, the formations are heavily stained black.