A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order Anura. Frog species with rough skin texture due to wart-like parotoi
European fire-bellied toad (Bombina bombina)
Panamanian golden frog (Atelopus zeteki)
Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibi
Archaeothyris, one of the most basal synapsids, first appears in the fossil records about 306 million years ago.
By the Mesozoic, 150 million years ago, sauropsids included the largest animals anywhere. Shown are some late Jurassic dinosaurs, including the early bird Archaeopteryx perched on a tree stump.