Snail-eating frogs from the Ethiopian highlands: a new anuran specialization

Morphological studies and analysis of gut contents indicate that two species of montane Ethiopian frogs are specialized for selective feeding on terrestrial gastropod mollusks. Certain bony elements of the skull, such as the palatines and prevomers, are reduced and deflected dorsally, while lateral elements of the maxillary arch, such as die quadratojugals and maxillaries, are expanded. The nasal apparatus in both species is situated in an extreme anterior position. The two species are removed from the genus Kassina Girard and placed in the genus Tornierella Ahl. Morphology of the head suggests that these frogs grasp mollusks with their jaws, pull them from the substrate, and swallow them whole. The sensory cues which trigger feeding are as yet unknown. Apparently, these frogs are the first terrestrial vertebrates known to feed exclusively on whole mollusks, without crushing them or removing the soft parts from the shell.