Meeting Abstract
Lungfishes (Sarcopterygii:Dipnoi) use strong suction feeding to capture their prey and cyclic chewing to process their food. The skulls of living lungfishes show a substantial reduction in cranial bones compared to actinopterygians, yet still possess a more kinetic skull than extant tetrapods. Despite skull fusion in the feeding apparatus, suction feeding is proficient, suggesting that these animals have developed novel suction kinematics to obtain their prey. Using X-ray Reconstruction of Moving Morphology, we focused on the initial suction strike and determined relative movements of five bones—pterygoid (upper tooth plate), prearticular (lower tooth plate), left and right ceratohyal, and neurocranium—during prey capture in the West African Lungfish, Protopterus annectens (N=3 individuals, 15 strikes). Cranial elevation and pterygoid motion were minimal, with rapid lower jaw depression preceding the movement of the ceratohyal. The jaw joint is hinge-like, where the majority of the movement is restricted about the mediolateral axis. The left and right ceratohyals are extremely mobile, undergoing dorso-ventral depression, rotation in all three degrees of freedom, and some translation posteriorly, enabled by an unfused symphysis and no bony connection to the skull. Hyoid timing is highly variable relative to jaw opening and closing, indicating decoupled linkage mechanics for modulation of buccal expansion and suction generation. The lungfish skull exhibits an intermediate stage of kinetic mobility between actinopterygians and tetrapods, with extreme hyoid mobility. NSF DEB 1541547.
