Hello,
There is a bit more known now, but not much. The lower jaw is flexible - when feeding the tongue is extruded through a groove the forms in the jaw...likely an adaptation for feeding underground.
The frog was known to cocoa, rubber and coffee plantation workers (prior to its recent description), who sometimes uncovered it at depths of 3 feet below the surface while digging. It burrows rapidly when unearthed..if placed on the surface it moves away by pulling itself along in a very "un-froglike" manner; possibly cannot hop or jump. A specimen kept in captivity remained uderground for 5 months without appearing on the surface, even at night (I assume a camera was set operating); assumed to feed underground and to be a termite specialist....sounds like a great one to go find and study!