 Temnospondyls first appeared in the Early Carboniferous around 330 million years ago ( Mya ) . During the Carboniferous , temnospondyls included basal medium @-@ sized forms such as Dendrerpeton or large semiaquatic forms such as Cochleosaurus . Other , more derived temnospondyls , such as the amphibamids , were smaller and more terrestrial . They resembled salamanders , and some taxa , such as the genus Branchiosaurus , even retained external gills like the modern @-@ day axolotl . During the latest Carboniferous and Early Permian around 300 Mya , several groups , such as the dissorophids and trematopids evolved strong , robust limbs and vertebrae and became adapted to life on land while others such as the eryopids , developed into large semiaquatic predators . The dvinosaurs , a group of small aquatic temnospondyls , evolved from terrestrial ancestors in the Late Carboniferous . 
 Temnospondyls first<a href='been_done' title='1'><mark></mark></a> appeared in the Early Carboniferous around 330 million years ago ( Mya ) . During the Carboniferous , temnospondyls included basal medium @-@ sized forms such as Dendrerpeton or large semiaquatic forms such as Cochleosaurus . Other , more derived temnospondyls , such as the amphibamids , <a href='uninflect' title='2'><mark>were</mark></a> smaller and more terrestrial . They resembled salamanders , and some taxa , such as the genus Branchiosaurus , even retained external gills like the modern @-@ day axolotl . During the latest Carboniferous and Early Permian around 300 Mya , several groups , such as the dissorophids and trematopids evolved strong , robust limbs and vertebrae and became adapted to life on land while others such as the eryopids , developed into large semiaquatic predators . The dvinosaurs , a group of small aquatic temnospondyls , evolved from terrestrial ancestors in the Late Carboniferous . 
Temnospondyls first been appeared in the Early Carboniferous around 330 million years ago ( Mya ) . During the Carboniferous , temnospondyls included basal medium @-@ sized forms such as Dendrerpeton or large semiaquatic forms such as Cochleosaurus . Other , more derived temnospondyls , such as da amphibamids , was smaller and more terrestrial . They resembled salamanders , and sum taxa , such as the genus Branchiosaurus , even retained external gills like tdamodern @-@ day axolotl . During the latest Carboniferous and Early Permian around 300 Mya , several groups , such as the dissorophids and trematopids evolved strong , robust limbs and vertebrae and became adapted to life on land while others such as the eryopids , developed into large semiaquatic predators . The dvinosaurs , a group of small aquatic temnospondyls , evolved from terrestrial ancestors in thdaate Carboniferous .