Abstract
The development of pharyngeal dentition was observed in the big head, Aristichthys nobilis, which is one of the hypophthalmichthyines of the cyprinids. This fish has the C-type larval dentition, in which no teeth ever occur at the position An3, and in which the first tooth at the position An2 is on the third replacement wave. So the positions Po 1, Ce0, An1 and An2 in the larval dentition correspond to the positions A4, A3, A2 and Al in the adult dentition, re-spectively. The initial tooth at each position is a conical one. The conical teeth are then changed to ones bearing a narrow grinding surface with a hook at the tip and some denticles on the margins. These teeth are of the Leuciscus stage. In the following teeth, the grinding surface is expanded, and the denticles are increased in number and distributed on not only the margins but also the whole grinding surface. These teeth bearing a very broad grinding surface characterize the hy-pophthalmichthyines. At the positions A2 to A4, the teeth become the hypophthalmichthyine type in the larval period. But the tooth at the position Al becomes the hypophthalmichthyine type in the juvenile period. The morphological change of teeth in this species is simple although their teeth are highly specialized. We think that this phenomenon gives a hint on their phylogeny.
