Meeting Abstract
With a few minor exceptions, suction feeding is unique to vertebrates, where it is almost ubiquitous among fish and aquatic tetrapods. This dominance reflects both effectiveness and constraints as even the aquatic lineages that have abandoned prey capture by suction feeding retain the mechanism and use it at some stage in the feeding process, during prey processing and manipulation if not during capture. I review major innovations in the suction feeding mechanism of teleosts, where this mechanism of prey capture is dominant among the over 32,000 species. Most teleosts have sufficient kinesis of cranial bones to allow the corners of the mouth opening to be filled during mouth opening. This produces a planar mouth opening that is often nearly circular in shape. Both features contribute to efficient flow of water into the mouth and help direct the region of influence to the area directly in front of the mouth aperture. In lineages that have secondarily lost the planar mouth aperture, which occurs in many groups that grab their prey with elongate jaws, suction is retained but is not effective until the prey reaches the region where the buccal cavity fully surrounds it, well posterior to the toothed region of the jaws. Jaw protrusion has multiple functions and has been shown to enhance the hydrodynamic forces that suction feeders exert on prey by increasing the rate of approach and hence the acceleration of fluid at the prey. Premaxillary protrusion has evolved five times in ray-finned fishes including two of the most successful teleost radiations, cypriniforms and acanthomorphs (spiny-rayed fishes), and is found in about 60 percent of living teleost species. Diversification of the suction feeding mechanism and feeding behavior reveals that suction feeders with high suction capacity rarely approach the prey rapidly, while slender-bodied predators with low suction capacity show the full range of attack speeds.
