> Advocates of phylogenetic nomenclature regard the traditional category 'Reptilia' to be invalid, and prefer to use the 'Amniota' or rather 'Sauropsida' category, because not all descendants of a common ancestor are included. However, in practice, these non-cladistic classifications, such as reptile, fish, and amphibian, remain in use by some biologists, especially in popular books written for a general audience.