Piotr Naskrecki / Cross Frog (Oreophryne sp) male protecting his clutch of eggs, Papua New Guinea

Piotr Naskrecki / Cross Frog (Oreophryne sp) male from a newly discovered species protecting his clutch of eggs, Papua New Guinea

Piotr Naskrecki / Cross Frog (Oreophryne sp), newly discovered species, eggs, Papua New Guinea

Robert Valentic / Following the desert rains a Holy cross frog {Notaden benneti} comes to the surface after a long period underground, Nyngan, New South Wales, Australia

Robert Valentic / Poisonous rock frog (Odorrana hosii) next to stream along the Cross Island Trail, Tioman Island, Malaysia.

Melvin Grey / Tawny tree frog (Smilisca puma) adult. Lowland Rainforest, Costa Rica. Controlled conditions.

Guy Edwardes / New Granada cross-banded tree frog (Smilisca phaeota) in the rain, Costa Rica. Controlled conditions.

Alex Hyde / Veragua cross-banded treefrogs (Smilisca sordida) mating pair at night, Osa Peninsula, Costa Rica

Alex Hyde / Veragua cross-banded treefrogs (Smilisca sordida), Osa Peninsula, Costa Rica

Chien Lee / Frog (Oreophryne variabilis), Sulawesi, Indonesia

Suzi Eszterhas / Tarraco Treefrog (Smilisca phaeota), Osa Peninsula, Costa Rica

Thomas Marent / Tarraco Treefrog (Smilisca phaeota) trio in amplexus, Piedras Blancas National Park, Costa Rica