Biological aspects of the Permian dicynodont Oudenodon (Therapsida: Dicynodontia) deduced from bone histology and cross-sectional geometry
Bernard Price Institute for Palaeontological Research
Bone histology and cross-sectional geometry were used to examine the growth patterns and lifestyle habits of the Late Permian dicynodont, Oudenodon. Several limb bones were analysed, revealing rapidly deposited fibro-lamellar bone, interrupted by annuli or sometimes Lines of Arrested Growth. Peripheral slowly deposited parallel-fibred bone was observed in several elements. It is suggested that the initial growth of Oudenodon was rapid during the favourable growing season, but decreased or sometimes ceased completely during the unfavourable season. Growth was cyclical and may have been sensitive to environmental fluctuations. The slowly forming parallel-fibred bone towards the sub-periosteal surface in several elements indicates a permanent transition to slow growth and may reflect the onset of sexual maturity. Bone cross-sectional geometry results reveal a markedly thick cortex, indicating a possible modification for digging. These cross-sectional geometry values, in conjunction with the limb morphology, suggest that Oudenodon was fossorial.
Permian; dicynodont; histology