The complex vomeronasal structure of Dipsochelys giant tortoises and its identification as a true Jacobson's organ

The nasal structure of the western Indian Ocean Dipsochelys giant tortoises is described. These tortoises are known to possess structures facilitating 'nasal drinking'. Additional unique nasal features include the processus dorsalis vomerinus supporting an enlarged medial nasal gland and a 'tuberculum palatinum'. The medial nasal gland can be considered homologous to the vomeronasal organ (Jacobson's organ) and is connected directly to the tuberculum palatinum in the buccal cavity through the foramina praepalatina. An homologous vorneronasal organ with a direct buccal connection is also identified in existing literature accounts of the leatherback turtle Dermochelys coriacea and may have been overlooked in other Chelonia.