Philip J. Motta
Philip J. Motta
Office: SCA 304
Lab: SCA 301, SCA 305
Ph.D., University of Hawaii, 1980.
Ecological and Functional Morphology
Ecomorphology, functional morphology, feeding, fishes, behavior, biomechanics.
My research interests are in functional and ecological morphology, and behavior of fishes, particularly as it pertains to feeding. My graduate students work on ecomorphological, anatomical, functional morphological, biomechanical, or behavioral projects involving feeding in bony fishes, sharks, and rays. Most of my past research has been on tropical reef fishes and sharks. Some of this research has focused on the interaction between functional morphology, behavior and ecology. In addition, past and present research has investigated the anatomy and mechanics of feeding, feeding behavior, and the evolution of feeding mechanisms in fishes.
The goal of my current research is an understanding of the comparative functional morphology of the feeding mechanisms in elasmobranchs (sharks, skates and rays), the relationship of functional morphology to their feeding behavior, and the evolution of feeding mechanisms in sharks and rays. Sharks and rays present a unique opportunity to investigate the function and evolution of feeding systems in fishes and aquatic vertebrates. Sharks share a common ancestor with early bony fishes. From the early piscine feeding mechanism the amphibians and later amniote vertebrates evolved and modified their feeding mechanisms. The unquestionable evolutionary success of the elasmobranchs is in part due to a diversity of feeding mechanisms within this group of vertebrates, a group which dates back over 400 million years.
Compared to the many morphological, physiological and behavioral studies of feeding in bony fishes, however, relatively little is known about the function and evolution of feeding mechanisms in elasmobranchs. Together with my graduate students, I utilize a variety of techniques to understand feeding mechanisms in sharks and rays. These techniques include: anatomical dissection, CT scanning, mechanical modeling, electromyography, high speed digital video photography of captive animals, pressure and bite force measurement, underwater video photography, and evolutionary analyses to unravel historical changes.
To date my graduate students and I have and are investigating feeding in the lemon shark, nurse shark, bull shark, whale shark, sevengill shark, bonnethead shark, scalloped hammerhead shark, great hammerhead shark, winghead shark, spiny and smooth dogfish, horn shark, whitespotted bamboo shark, leopard shark, blacktip shark, sand tiger shark, cownose ray, guitarfish, lesser electric ray, yellow stingray, and Atlantic stingray. We have helped to elucidate the anatomy and functional morphology of the feeding mechanism in these sharks and rays, the behavior and kinematics (movement patterns) of prey capture, related bite force to jaw morphology, tested some of the functions of jaw protrusion, studied the evolution and function of jaw suspension types in sharks and rays, tested for modulatory abilities during prey capture (the ability to change or modify feeding patterns with different prey types), investigated ontogenetic patterns in prey capture kinematics and morphology, studied tooth structure and cutting biomechanics, and discussed the evolution of their jaw mechanisms. Complementing this work on sharks and rays, former graduate and undergraduate students have investigated ray movement patterns and feeding, ontogeny of prey capture in largemouth bass, prey capture kinematics and bite force in barracuda, gar and needlefish, the functional morphology of suction generation in remora, and the ecomorphology of feeding in cichlid fishes.
Our current research investigates a variety of ancestral and derived shark species encompassing many feeding types. In these diverse species, we are investigating the relationship of feeding mechanisms and bite force to jaw suspension types, functional specialization for suction feeding, the evolution and biomechanics of shark teeth, and the evolution and functional morphology of the hammerhead cephalofoil. The anatomy and functional morphology of whale shark feeding mechanisms is underway with both laboratory and field research.
Two of my six graduate students are also investigating the functional anatomy and bite force in barracuda, and habitat utilization of goliath grouper in the Gulf of Mexico. Past applied research involved an analysis of bite patterns of sharks and bony fishes on submarine towed arrays and material testing of underwater hoses and their ability to resist puncture by bony fishes and sharks. Supporting this research our lab has embarked on a project to analyze bite force production in large carcharhinid sharks.