Meeting Abstract
Teeth are diverse in their morphology and function among fishes to accommodate a variety of feeding and prey capture strategies. Fully formed teeth typically require rigid attachments to the jaws, but attachments for developing teeth must be mobile to accommodate growth. Therefore teeth are typically non-functional while developing and only become functional once they become fixed (“ankylosed”) to the jaw. Goosefish (Lophius americanus) have some ankylosed teeth along the labial rim of the jaw but also have a large proportion of half-developed teeth, which are attached only on the lingual side by a ligament. This provides a hinging mechanism that allows the teeth to bend freely to allow prey into the mouth, while the ligament locks the teeth in place labially to prevent prey from leaving the mouth. We used a lever motor and high-speed video to test resistance to bending of both tooth types (ankylosed and hinged) in both lingual and labial directions. The hinged teeth bend more than 90 degrees in the lingual direction with little force (less than 1 Newton), whereas almost no bending (less than 10 degrees) is seen with high forces (above 8 Newtons) in the labial direction. Ankylosed teeth bent little in either direction. We also examined this ligament histologically via paraffin embedding and generalilzed contrast stain. This ligament is composed entirely of collagen (with no elastin), suggesting that the ligament is inelastic. This study demonstrates functional utility during multiple phases of tooth development in goosefish.
