Abstract This paper reviews the morphological diversity of the anterior dentition (AD - incisors and canines) in fossil and extant mammals. The great diversity of the mammalian anterior dentition is due to mosaic evolution of different morphological features. The paper identifies twenty-one groups of genera that share specific features but are not phylogenetically related. These groups are referred to as clusters. Minor differences within the clusters are described as modifications that are found in the different mammalian orders. The clusters highlight convergent features as well as evolutionary trends that occur in different clusters, such as the reduction of antemolars, the formation of incisiform lower canines and of caniniform lower premolars. The different functions of the anterior teeth within these clusters are discussed. They suggest that adaptations for quite different functions have led to very similar structures. During evolution, the reduction of anterior teeth is rare in carnivores but common in herbivores. This illustrates the increasing importance of soft parts, such as lips, tongue and trunk for foraging. The setup of the clusters described here is not intended as an additional system to which taxa must be assigned, but as a framework for highlighting similarities in unrelated taxa.
Wighart von Koenigswald (Wed,) studied this question.