A survey of tooth attachment histology in Squamata: The evaluation of tooth attachment classifications and characters

Various classifications of tooth attachment were reviewed and their historic usage evaluated. The traditional terminologies were determined to be useful for descriptive purposes. The utility of using traditional terms as character states in published phylogenetic analyses was tested empirically using new squamate dental histology data. I surveyed the dental attachment histology of 35 species of squamates. Acellular and cellular cement attached squamate tooth roots to the tooth attachment sites made of alveolar bone. Tooth attachment type was invalidated as an informative character in squamate phylogenetic analyses. Other published characters were valid with some modification. Attachment site vascularization, and the presence of acellular cement covering the tooth crown were introduced as characters worthy of investigation for use in phylogenetic analyses of squamates. It was concluded that discussions on the evolution of vertebrate tooth attachment are impeded with the retention of the traditional terminology and the examination of only gross morphology.