The current classification of mammals is based on phylogenetic criteria, which are discussed in an introductory manner. During the 19th century, only Florentino Ameghino applied this criterion. Consequently, until the end of the 20th century, many classifications of glyptodonts were confusing and offered little explanation in light of evolution. Currently, the phylogenetic approach allows for a better understanding of the diversity and relationships among the numerous glyptodont lineages.