Ontogenetic studies of early Cenozoic Coryphodon (Mammalia, Pantodonta)

Abstract

Juvenile specimens of the Paleocene–Eocene pantodont Coryphodon provide more extensive ontogenetic information for this genus than is available for other Paleocene–Eocene mammals. The dental eruption sequence for Coryphodon is: 1) (DC11, DI1–31–3); 2) DP44; 3) DP33; 4) DP22; 5) (M11, I33); 6) DP11, 7) M22; 8) P44; 9) P33; 10) (P22, I11?); 11) C11; 12) (M33, I22) (eruption sequence of tooth positions in parentheses is uncertain). The DP11 of Coryphodon do not have permanent successors. No significant, qualitative morphological variation can be detected in deciduous cheek teeth of Coryphodon, and metric analysis of these teeth failed to detect taxonomically significant differences. The ontogenetically youngest Coryphodon is known from parts of a skeleton of an individual perhaps less than three years old at the time of death. This skeleton and other partial juvenile skeletons suggest that juvenile Coryphodon grew quickly and approached near-adult proportions before the deciduous dentition was lost or the epiphyses of the long bones began to fuse.