Figure 1.

Scanning electron microscopy of frog tongue surfaces. All images are at the same scale. A – Bombina variegata, B – Discoglossus pictus, C – Ceratophrys ornata, D – Litoria infrafrenata, E – Megophrys nasuta, F – Rana (Lithobates) pipiens, G – Bufo bufo, H – Oophaga histrionica. Frog tongue surfaces are covered by fungiform papillae (arrows), which are embedded in a matrix of smaller filiform papillae. The examined species differ notably in the size and the shape of the papillary surface structures.