Seymouria

Seymouria was an amphibian tetrapod from the early Permian of North America and Europe, about 280 to 270 million years ago (mya). It was small, only 2 ft (60 cm) long. 
As an adult animal, "Seymouria" was well adapted to life on land, with many reptilian features. It was for quite a long time thought to be a primitive reptile. It is now known that its early life stages were in water. Apparently, it is an "amphibian" whose adult stage was adapted for life in a dry climate.
The discovery of its amphibian nature was a considerable surprise.
The adult skeletons were first found in the red beds of Texas and Oklahoma. These beds were laid down in the huge delta complex of a large river flowing towards a coast, much like the Mississippi of today. The species found in Germany and New Mexico, "Seymouria sanjuanensis", had massive legs and held its body well off the ground. This shows an "effective adaptation to terrestrial locomotion".
A simplified life cycle might be: eggs laid in water, larval stages in water, young animal with limbs climbs out and instinctively moves to higher ground. All its life lived as a carnivore on dry land, returning to water occasionally to drink and to breed. The adults would be able to operate in a fairly dry climate.