Temnospondyli

Temnospondyli is a diverse and extinct group of tetrapods that were most abundant during the Permian and Triassic periods. They are often referred to as "stem-amphibians" due to their evolutionary position as a paraphyletic assemblage ancestral to modern amphibians. These ancient creatures varied significantly in size and appearance, ranging from small, salamander-like forms to large, crocodile-like predators. Many temnospondyls possessed flattened skulls, external gills in their larval stages, and a combination of aquatic and terrestrial adaptations. Their fossils are found worldwide, indicating a widespread distribution across various ancient environments, including freshwater lakes, rivers, and swamps. The group includes a wide array of families and genera, such as Eryops, Mastodonsaurus, and Labyrinthodonts, the latter being a broader, informal grouping often encompassing many temnospondyls. Temnospondyls played a significant role in Paleozoic and Mesozoic ecosystems, occupying ecological niches similar to those of modern amphibians and some reptiles. Their decline is thought to have occurred in the early Cretaceous period, with few surviving into later geological ages.