In 1997 two isolated hominid molars were recovered from the Plio-Pleistocene site named Gondolin, in the North West Province, South Africa. One of these teeth (GDA-2) is a left mandibular M2 that was characterised as Paranthropus sp. indet. (Menter et al., 1999). A more specific taxonomic affiliation was not considered because a number of enigmatic morphological features of GDA-2 are normally attributed to ‘hyper-robust’ east African Paranthropus taxa, in particular its large crown size and the presence of two distal accessory (C6) cusps. This chapter presents a discussion of research in the evolutionary development of teeth, focusing on developmental processes relating to molar tooth crown size and cusp morphology. Details of the GDA-2 crown and cusp morphology are discussed in the context of enamel–dentine junction (EDJ) formation, enamel knots and related aspects of a tooth’s developmental biology. This approach is useful in furthering our understanding of early hominid variation, adaptation and development.