Page "Reptile" Paragraph 29

By the 21st century, vertebrate paleontologists were beginning to adopt phylogenetic taxonomy, in which all groups are defined in such a way as to be monophyletic ; that is, groups include all descendants of a particular ancestor.

The reptiles as historically defined would be paraphyletic, since they exclude both birds and mammals, although these also evolved from animals like dinosaurs and early therapsids that were traditionally called reptiles.

Colin Tudge wrote: