Tooth length and occlusion in four species of piscivorous fishes: getting a grip on prey

Abstract

Fitness is in part determined by the success of prey capture, often achieved in marine piscivores using teeth to capture and process prey. In ram feeding piscivores, a pattern of monognathic heterodonty has been observed where tooth size either increases posteriorly (Scomberomorus maculatus), or anteriorly (Carcharhinus limbatus), with exceptions such as Trichiurus lepturus and Sphyraena barracuda which have large anterior fangs. Tooth size and placement, as related to prey capture, was examined in Atlantic Spanish Mackerel (S. maculatus), Great Barracuda (S. barracuda), Atlantic Cutlassfish (T. lepturus), and the Blacktip shark (C. limbatus) by quantifying tooth occlusion along the jaw. Percent gape at occlusion in S. maculatus decreased anteriorly in a linear fashion, indicating occlusion from posterior to anterior. Therefore, prey initially contact the posterior teeth with high puncture pressure during high velocity strikes, capitalizing the region of greatest bite force. For S. barracuda and T. lepturus, posterior teeth and premaxillary fangs occlude at similar percent gapes (within 10%). The premaxillary fangs are likely used for initial capture due to the high angular velocity of the anterior section of the jaw and then for cutting, due to their laterally compressed shape. In C. limbatus all teeth occluded within a narrow range of 1.4–8.8% gape, indicating that all teeth meet at almost complete jaw closure. Simultaneous puncture of teeth prevents prey escape while maximizing the cutting area during head shaking. Thus, various tooth size and dentition patterns may yield similar success in prey capture, serving the same function.