Pneumatic osteolysis in a cetacean (Orcaella brevirostris)

Abstract

Pneumatic osteolysis (excessive pneumatisation of cranial bones) previously reported for certain terrestrial mammals (rhinoceroses, elephants, gorilla) is here reported in the Irrawaddy dolphin (Orcaella brevirostris). The osteological evidence provided by all mammal forms studied indicates unequivocally that, in the complex process of bone pneumatization (whether normal or excessive in range), the initiative lies with the peculiarly specialized mucosa of the pneumatic spaces concerned.