Reptiles

 The reptiles are a former group of vertebrates terrestresque they reached in the past a great summit, dominating the whole planet. The later appearance of birds and mammals from them and with solutions mas advanced, it reduced them to his current distribution. The reptiles constitute a big step in the conquest of the terrestrial way on the part of the animals, since they manage already to become free completely of the water. His extremities possess also a major capacity of support, being able to raise the body of the soil and improve this way the locomotion.

The serpents, they are tetrapodos that have lost his four extremities as a secondary evolution.