Feeding systems of living dipnoi: Anatomy and function

Living lungfishes capture prey by means of suction and then use a simple “hydraulic” transport system to position it for processing between the tooth plates. Three major morphological features–‐an autostylic jaw suspension, tooth plates, and a reduced but highly mobile branchial apparatus–‐largely determine the special cranial morphology of living dipnoans and are directly related to these feeding functions. Within Dipnoi, however, there are many striking and functionally significant differences between Neoceratodus and the lepidosirenid genera. These include the structure of the tooth plates, lower jaw, jaw articulation, skull roof, tongue, lips, and jaw closing and opening muscles. For example, the rami of the lower jaw of Neoceratodus flex slightly at the symphysis, and the jaw joint is “unrestrictive.” As a result, the upper and lower tooth plates can be ground against each other in a fashion distinct from the precise and restricted occlusion of lepidosirenids. Understanding the anatomy and function of these features will ultimately aid in interpreting the evolution of dipnoan feeding systems.