Growth, function and homology: aspects of dental replacement in toothcombed strepsirhines.

In maturing juvenile lemurs and lorises, it was found that the anteriormost lower deciduous premolar migrates forward and may become associated with the teeth of the toothcomb; this is similar to previous observations on the dentition of indriines. The mesial shift of dp2 appears to be associated with the eruption of P2 but, more importantly, also with replacement of the deciduous by the permanent teeth of the toothcomb--which is a period of functional disruption at the front of the jaw. It is suggested that this growth-related phenomenon should not be confused with other aspects of dental development and eruption which might be indicative of homology.