Lissamphibia has previously been used to include all extant amphibians, while excluding the main Paleozoic tetrapod groups. There is debate as to whether it constitutes a clade. Some writers argue that Gerobatrachus hottoni (early Permian) belongs in Lissamphibia. For more details, see Lissamphibia on Wikipedia.
From Ancient Greek λισσός (lissos, “smooth”) + ἀμφίβια (amphibia), nominative neuter plural of ἀμφίβιος (amphibios, “two types of life”), from ἀμφί (amphi, “of both kinds”) + βίος (bios, “life”).