Lepospondyli

a subclass of amphibians, first appearing in the middle Carboniferous period. It was a diverse group united on the basis of the common structure of the vertebrae (which were lepospondylous). Most species were relatively small animals, the largest measuring about 1 m, and they were insectivores. The subclass includes the orders Nectridea and Aistopoda from the Carboniferous and early Permian periods, Lisoropha from the late Triassic and the Carboniferous periods, and sometimes the Caudata and the Apoda. Remains of ancient lepospondyls are quite abundant in the United States and Western Europe and serve as good index fossils for the stratigraphy of the continental deposits of the late Paleozoic.