Modulation in Feeding Kinematics and Motor Pattern of the Nurse Shark <Emphasis Type="Italic">Ginglymostoma cirratum</Emphasis>

Synopsis Studies of feeding in bony fishes have almost universally demonstrated the ability of individuals to modulate their method of capture in response to differing stimuli. Preliminary evidence indicates that morphologically specialized inertial suction feeding sharks are the most likely fishes to lack inherent modulatory ability. We examined the ability of the nurse shark, Ginglymostoma cirratum, to modulate its feeding behavior based on different food types and sizes. G. cirratum is an inertial suction feeding fish that is apparently stereotyped in its food capture behavior. Electromyography showed no statistical difference between feeding motor patterns based on food type (squid or fish) or size (gape width or twice gape width), although there were slight inter-individual differences in the onset of muscle firing for some muscles. Kinematic analysis showed a statistical difference in variables associated with durations for different food types, with the durations for all variables being faster for squid bites than fish bites, but no difference based on the size of the food item. This apparent lack of modulation may be associated with specialization of the morphology and behavior of G. cirratum for obligate suction prey capture. This functional specialization constrains the method in which G. cirratum captures prey but does not appear to result in dietary specialization. An unusual post capture spit-suck manipulation allows this shark to handle and ingest large prey.     

Anatomy of the feeding apparatus of the nurse shark,Ginglymostoma cirratum

The anatomy of the feeding apparatus of the nurse shark, Ginglymostoma cirratum, was investigated by gross dissection and computer axial tomography. The labial cartilages, jaws, jaw suspension, muscles, and ligaments of the head are described. Palatoquadrate cartilages articulate with the chondrocranium caudally by short, laterally projecting hyomandibulae and rostrally by ethmoorbital articulations. Short orbital processes of the palatoquadrates are joined to the ethmoid region of the chondrocranium by short, thin ethmopalatine ligaments. In addition, various ligaments, muscles, and the integument contribute to the suspension of the jaws. When the mouth is closed and the palatoquadrate retracted, the palatine process of the palatoquadrate is braced against the ventral surface of the nasal capsule and the ascending process of the palatoquadrate is in contact with the rostrodorsal end of the suborbital shelf. When the mandible is depressed and the palatoquadrate protrudes slightly rostroventrally, the palatoquadrate moves away from the chondrocranium. A dual articulation of the quadratomandibular joint restricts lateral movement between the mandible and the palatoquadrate. The vertically oriented preorbitalis muscle spans the gape and is hypothesized to contribute to the generation of powerful crushing forces for its hard prey. The attachment of the preorbitalis to the prominent labial cartilages is also hypothesized to assist in the retraction of the labial cartilages during jaw closure. Separate levator palatoquadrati and spiracularis muscles, which are longitudinally oriented and attach the chondrocranium to the palatoquadrate, are hypothesized to assist in the retraction of the palatoquadrate during the recovery phase of feeding kinematics. Morphological specializations for suction feeding that contribute to large subambient suction pressures include hypertrophied coracohyoideus and coracobranchiales muscles to depress the hyoid and branchial arches, a small oral aperture with well‐developed labial cartilages that occlude the gape laterally, and small teeth. J. Morphol. 241:33–60, 1999. © 1999 Wiley‐Liss, Inc.     

Prey capture in the pike-perch,Stizostedion lucioperca (teleostei,percidae): A structural and functional analysis

Summary The pike-perch,Stizostedion lucioperca, uses both suction and grasping during feeding. Type, size, and position of prey and predator determine the movement of catching. This is concluded from simultaneous motion analysis, electromyography, and the record of pressures inside the buccopharyngeal cavity during feeding. The EMG incorporates 24 muscles of the head, including the branchial basket and the anterior body musculature. When the pike-perch begins to feed acceleration and expansion of the head parts determine the negative buccopharyngeal pressure and therefore the suction force applied to different preys. Not the head muscles, but the epaxial and hypaxial body musculatures provide the main force for the rapid expansion of the head through movements of the neurocranium, pectoral girdle, and hyoid arch. Despite the lack of a true neck, the pike-perch is able to move its neurocranium in all directions to aim the suction force. The experiments revealed that ventral and lateral movements aid in the ingestion of a big prey after it has been grasped with the teeth. The head muscles are active as regulators of the opening movements and in the closing movements. Variable overlaps of ab- and adductor activity show that their contraction patterns are interdependent. Variations in the recorded pressures can be related largely to a series of EMGs showing different starting moments of adductor contraction. In this progressive series two patterns were distinguished, and their accompanying movements were compared and related to the type of prey. According to the feeding behavior and morphology, the pike-perch is classified as a rapacious predator. Comparison with some other voracious fishes shows that besides the total length of the lower jaw and the dentigerous area, the construction and dentition of the upper jaws and the anterior suspensorial and neurocranial parts are also important features of this ecological type. However it appears that the fishes selected for this comparison use suction rather than the teeth as the main means of catching the smaller, but commonly eaten prey. The teeth prevent escape after capture by sucking and they increase the maximum prey size that can be caught. In this group, the head ofStizostedion appears to be comparatively well adapted to sucking with grasping adaptations.     

The suction mechanism of the pipid frog,Pipa pipa (Linnaeus, 1758)

Most suction‐feeding, aquatic vertebrates create suction by rapidly enlarging the oral cavity and pharynx. Forceful enlargement of the pharynx is powered by longitudinal muscles that retract skeletal elements of the hyoid, more caudal branchial arches, and, in many fish, the pectoral girdle. This arrangement was thought to characterize all suction‐feeding vertebrates. However, it does not exist in the permanently aquatic, tongueless Pipa pipa , an Amazonian frog that can catch fish. Correlating high‐speed (250 and 500 fps) video records with anatomical analysis and functional tests shows that fundamental features of tetrapod body design are altered to allow P. pipa to suction‐feed. In P. pipa , the hyoid apparatus is not connected to the skull and is enclosed by the pectoral girdle. The major retractor of the hyoid apparatus arises not from the pectoral girdle but from the femur, which lies largely within the soft tissue boundaries of the trunk. Retraction of the hyoid is coupled with expansion of the anterior trunk, which occurs when the hypertrophied ventral pectoral elements are depressed and the urostyle and sacral vertebra are protracted and slide forward on the pelvic girdle, thereby elongating the entire trunk. We suggest that a single, robust pair of muscles adduct the cleithra to depress the ventral pectoral elements with force, while modified tail muscles slide the axial skeleton cranially on the pelvic girdle. Combined hyoid retraction, axial protraction, and pectoral depression expand the buccopharyngeal cavity to a volume potentially equal to that of the entire resting body of the frog. Pipa may be the only tetrapod vertebrate clade that enlarges its entire trunk during suction‐feeding.     

Morphology and function of the feeding apparatus of the lungfish, Lepidosiren paradoxa (Dipnoi)

The feeding mechanism of the South American lungfish, Lepidosiren paradoxa retains many primitive teleostome characteristics. In particular, the process of initial prey capture shares four salient functional features with other primitive vertebrates: 1) prey capture by suction feeding, 2) cranial elevation at the cranio-vertebral joint during the mouth opening phase of the strike, 3) the hyoid apparatus plays a major role in mediating expansion of the oral cavity and is one biomechanical pathway involved in depressing the mandible, and 4) peak hyoid excursion occurs after maximum gape is achieved. Lepidosiren also possesses four key morphological and functional specializations of the feeding mechanism: 1) tooth plates, 2) an enlarged cranial rib serving as a site for the origin of muscles depressing the hyoid apparatus, 3) a depressor mandibulae muscle, apparently not homologous to that of amphibians, and 4) a complex sequence of manipulation and chewing of prey in the oral cavity prior to swallowing. The depressor mandibulae is always active during mouth opening, in contrast to some previous suggestions. Chewing cycles include alternating adduction and transport phases. Between each adduction, food may be transported in or out of the buccal cavity to position it between the tooth plates. The depressor mandibulae muscle is active in a double-burst pattern during chewing, with the larger second burst serving to open the mouth during prey transport. Swallowing is characterized by prolonged activity in the hyoid constrictor musculature and the geniothoracicus. Lepidosiren uses hydraulic transport achieved by movements of the hyoid apparatus to position prey within the oral cavity. This function is analogous to that of the tongue in many tetrapods.     

Comparative anatomy and evolutionary history of suction feeding in cetaceans

Some odontocetes possess unique features of the hyolingual apparatus that are involved in suction feeding. The hyoid bone and associated musculature generates rapid, piston‐like retraction, and depression of the hyoid and tongue. “Capture” suction feeders (e.g., Globicephala) use suction for capturing and swallowing prey. “Combination” feeders (i.e., Lagenorhynchus) use both raptorial feeding (to capture prey) and suction (to ingest prey). In “capture” suction feeders, features of the hyoid and skull have been attributed to creating suction (i.e., large surface area and mandibular bluntness). In addition to odontocetes, a mysticete, the gray whale (Eschrichtius robustus), is considered a benthic suction feeder. However, anatomical studies of purported suction‐feeding structures of the gray whale are lacking. In addition, few studies have utilized evolutionary approaches to understand the history of suction feeding in cetaceans. This study incorporates quantitative and qualitative hyoid and cranial data from 35 extant and 14 extinct cetacean species into a multivariate principal component analysis and comparative phylogenetic analyses. Conclusions from these analyses are that some commonly attributed features (i.e., ventral throat grooves and mandibular bluntness) and one principal component are significantly correlated with suction feeding. Finally, ancestral state reconstructions indicate that suction feeding likely evolved once, early in cetacean evolutionary history.     

Hyoid and pharyngeal arch function during ventilation and feeding in elasmobranchs: Conservation and modification in function

The hypothesis that the mandibular and hyoid arches evolved from anterior pharyngeal arches to increase ventilation performance and subsequently became adapted for feeding is widely accepted. As jaws evolved, the morphology of the hyoid arch changed notably from that of a pharyngeal arch. Furthermore, hyoid arch morphology varies considerably among elasmobranch taxa and has been shown to be related to feeding style. The goal of this study is to determine whether the function (direction of movement or change in cavity cross‐section) of the hyoid arch is altered from that of the pharyngeal arch, and whether function is altered between ventilation, the basal behavior, and feeding, the derived behavior. Similar effects and associations of the pharyngeal arches by orientation to feeding or ventilation are also investigated. The kinematics of the hyoid and second pharyngeal arch during ventilation and feeding are quantified using sonomicrometry and hyomandibular angle measured in five shark and one skate species representing widely divergent hyomandibular morphologies. Hyoid and pharyngeal cavity width follows the same pattern of movement during ventilation; therefore the hyoid arch retains the ancestral function of the pharyngeal arches. The orientation of the hyomandibular cartilage appears to influence the pattern of arch movement during ventilation: anterior directed elements decrease in cavity width; laterally directed elements increase in cavity width; while posterior directed elements increase in cavity width or do not change; while cavity depth increases in all species. Hyoid and pharyngeal cavity width movement differs among the species during feeding and also appears to be related to hyoid arch orientation as well as feeding style. There appears to be a division between those species with hyomandibular angles less than 110° from those that are greater between feeding mode and hyoid cavity width movement. Primarily suction feeding species decrease hyoid cavity width whereas primarily bite feeding species increase hyoid cavity width during feeding while all species increase hyoid cavity depth.     

Osteology,myology and feeding mechanism of Astronotus ocellatus (Pisces,Perciformes)

Summary Astronotus ocellatus captures its prey by creating a negative pressure in the buccal cavity which is caused by its quick expansion. Once the prey has been accommodated, the buccal cavity undergoes a compression which may propel the prey towards the pharyngeal jaws for mastication. The motion picture recordings indicate retracted premaxillae at the beginning of food intake followed by a maximum attainment of mouth gape and then mastication. During the maximum opening of the mouth the premaxillae are protruded and dentaries are at maximum depression. These events are followed by activities such as buccopharyngeal cavity expansion, bulging on the ventral surface of the head, and prominent curvature on the ventral surface anterior to the urohyal, caused by the upward movement of the glossohyal. Based on the cinematographic results, it may be inferred that the maximum mouth gape is caused by the sternohyoid-hyoid-interopercular-mandible coupling, and not by the opercular apparatus-mandible coupling, as the latter acts after the full descent of the lower jaw. Impression of the expanded buccopharyngeal cavity has been made by a paraffin mold technique, which confirms the displacement of the buccopharyngeal elements during expansion of the cavity.     

Food capture kinematics of the suction feeding horn shark, Heterodontus francisci

The goal of this study was to examine the feeding kinematics of the horn shark, Heterodontus francisci, a member of the most basal clade of galeomorph sharks, the Heterodontiformes. The accessibility of the food was manipulated to determine if the horn shark modulated capture. Three different methods of presenting food were used to mimic the different positions of prey items found in the natural diet of the horn shark. Food was presented unattached to the substrate, securely attached, or fitted snugly in a tube. Using high-speed video kinematic analysis, capture events were examined. Heterodontus francisci uses inertial suction facilitated by rapid mandible depression and labial cartilage protrusion to capture food. The horn shark conforms to a capture kinematic profile characteristic of both basal and derived inertial suction feeding sharks. Unusual post-capture behaviors include body leveraging, use of the mouth to form a seal over food, and chisel-like palatoquadrate protrusion. When presented with food of different accessibility, Heterodontus francisci used one consistent kinematic pattern for capture that was not modulated. Only post-capture behaviors varied according to food accessibility.     

Functional morphology of the feeding system in the ruff — Gymnocephalus cernua (L. 1758) — (Teleostei,Percidae)

The ruff, Gymnocephalus cernua, is a European freshwater fish that feeds by sucking up small invertebrates from the bottom of ponds and slow flowing rivers. The feeding movements have been studied by simultaneous electromyography of seventeen muscles of the head and cinematographic techniques. A theoretical model of movements imposes the functional demands of suction upon an abstraction of the form of a teleost head. Three phases in the feeding act, a preparatory phase, a suction phase and a transport phase, could be correlated with the observed movements and EMGs. Differences between the predicted and the actual movement are discussed. Two different types of feeding occur. The direction, magnitude and duration of the suction forces during feeding are modified, according to the position of the prey. A mechanism preventing early mandibular depression allows sudden and strong suction. Retardation of the suspensorial abduction during the overall expansion of the buccal cavity is ascribed to kinetic interrelations with the hyoid arch. Protrusion of the upper jaws also permits an earlier closure of the mouth and directs the food-containing waterflow posteriorly. When the fish is feeding on sinking prey, protrusion occurs later in the sequence of movements than when it is feeding from the bottom. As the protruded jaws produce a downwardly pointed mouth this retardation aims the suction force.     

Hyoid morphology and movements relative to abducting forces during feeding in Astatotilapia elegans (Teleostei: Cichlidae)

In fishes, the abducting hyoid bars push the suspensoria outwards. This force transmission is generally assumed to be important during fast suction feeding (strenuous activity). In Astatotilapia elegans the hyoid symphysis can best be modelled as an oblique hinge. The relevance of this hinge morphology on the force transmission has been studied by means of a three-dimensional (3D) model simulating the displacements of the hyoid-suspensorial system. It appears that the transmission force factor increases throughout feeding in the case of the hinge model. Reduction of the hyoid symphysis to a point articulation (as was done formerly in attempts to quantify the transmission by means of planar models) suggests an unfavourable decline of the transmission force to zero during maximal mouth expansion. The angle between the hinge axis of the symphysis and the longitudinal axis of the hyoid bar is 45°. Such a configuration allows for a maximal increase in the volume of the buccal cavity for suction. This functional aspect, together with the apparent maximization of the force transmission during feeding, suggests that constructional and neuromotoric factors have been improved during the evolutionary development of the hyoid-suspensorial system.     

Advances in the Study of Feeding Behaviors, Mechanisms, and Mechanics of Sharks

Sharks as a group have a long history as highly successful predatory fishes. Although, the number of recent studies on their diet, feeding behavior, feeding mechanism, and mechanics have increased, many areas still require additional investigation. Dietary studies of sharks are generally more abundant than those on feeding activity patterns, and most of the studies are confined to relatively few species, many being carcharhiniform sharks. These studies reveal that sharks are generally asynchronous opportunistic feeders on the most abundant prey item, which are primarily other fishes. Studies of natural feeding behavior are few and many observations of feeding behavior are based on anecdotal reports. To capture their prey sharks either ram, suction, bite, filter, or use a combination of these behaviors. Foraging may be solitary or aggregate, and while cooperative foraging has been hypothesized it has not been conclusively demonstrated. Studies on the anatomy of the feeding mechanism are abundant and thorough, and far exceed the number of functional studies. Many of these studies have investigated the functional role of morphological features such as the protrusible upper jaw, but only recently have we begun to interpret the mechanics of the feeding apparatus and how it affects feeding behavior. Teeth are represented in the fossil record and are readily available in extant sharks. Therefore much is known about their morphology but again functional studies are primarily theoretical and await experimental analysis. Recent mechanistic approaches to the study of prey capture have revealed that kinematic and motor patterns are conserved in many species and that the ability to modulate feeding behavior varies greatly among taxa. In addition, the relationship of jaw suspension to feeding behavior is not as clear as was once believed, and contrary to previous interpretations upper jaw protrusibility appears to be related to the morphology of the upper jaw-chondrocranial articulation rather than the type of jaw suspension. Finally, we propose a set of specific hypotheses including: (1) The functional specialization for suction feeding hypothesis that morphological and functional specialization for suction feeding has repeatedly arisen in numerous elasmobranch lineages, (2) The aquatic suction feeding functional convergence hypothesis that similar hydrodynamic constraints in bony fishes and sharks result in convergent morphological and functional specializations for suction feeding in both groups, (3) The feeding modulation hypothesis that suction capture events in sharks are more stereotyped and therefore less modulated compared to ram and bite capture events, and (4) The independence of jaw suspension and feeding behavior hypothesis whereby the traditional categorization of jaw suspension types in sharks is not a good predictor of jaw mobility and prey capture behavior. Together with a set of questions these hypotheses help to guide future research on the feeding biology of sharks.     

Reconstruction of cranial and hyobranchial muscles in the triassic temnospondyl Gerrothorax provides evidence for akinetic suction feeding

The cranial and hyobranchial muscles of the Triassic temnospondyl Gerrothorax have been reconstructed based on direct evidence (spatial limitations, ossified muscle insertion sites on skull, mandible, and hyobranchium) and on phylogenetic reasoning (with extant basal actinopterygians and caudates as bracketing taxa). The skeletal and soft‐anatomical data allow the reconstruction of the feeding strike of this bottom‐dwelling, aquatic temnospondyl. The orientation of the muscle scars on the postglenoid area of the mandible indicates that the depressor mandibulae was indeed used for lowering the mandible and not to raise the skull as supposed previously and implies that the skull including the mandible must have been lifted off the ground during prey capture. It can thus be assumed that Gerrothorax raised the head toward the prey with the jaws still closed. Analogous to the bracketing taxa, subsequent mouth opening was caused by action of the strong epaxial muscles (further elevation of the head) and the depressor mandibulae and rectus cervicis (lowering of the mandible). During mouth opening, the action of the rectus cervicis muscle also rotated the hyobranchial apparatus ventrally and caudally, thus expanding the buccal cavity and causing the inflow of water with the prey through the mouth opening. The strongly developed depressor mandibulae and rectus cervicis, and the well ossified, large quadrate‐articular joint suggest that this action occurred rapidly and that powerful suction was generated. Also, the jaw adductors were well developed and enabled a rapid mouth closure. In contrast to extant caudate larvae and most extant actinopterygians (teleosts), no cranial kinesis was possible in the Gerrothorax skull, and therefore suction feeding was not as elaborate as in these extant forms. This reconstruction may guide future studies of feeding in extinct aquatic tetrapods with ossified hyobranchial apparatus. J. Morphol., 2013. © 2012 Wiley Periodicals, Inc.     

Evolution and ecology of feeding in elasmobranchs

Paleozoic chondrichthyans had a large gape, numerous spike-liketeeth, limited cranial kinesis, and a non-suspensory hyoid,suggesting a feeding mechanism dominated by bite and ram. Modernsharks are characterized by a mobile upper jaw braced by a suspensoryhyoid arch that is highly kinetic. In batoids, the upper jawis dissociated from the cranium permitting extensive protrusionof the jaws. Similar to actinopterygians, the evolution of highlymobile mandibular and hyoid elements has been correlated withextensive radiation of feeding modes in elasmobranchs, particularlythat of suction. Modern elasmobranchs possess a remarkable varietyof feeding modes for a group containing so few species. Biting,suction or filter-feeding may be used in conjunction with ramto capture prey, with most species able to use a combinationof behaviors during a strike. Suction-feeding has repeatedlyarisen within all recent major elasmobranch clades and is associatedwith a suite of morphological and behavioral specializations.Prey capture in a diverse assemblage of purported suction-feedingelasmobranchs is investigated in this study. Drop in water pressuremeasured in the mouth and at the location of the prey showsthat suction inflow drops off rapidly with distance from thepredator's mouth. Elasmobranchs specializing in suction-feedingmay be limited to bottom associated prey and because of theirsmall gape may have a diet restricted to relatively small prey.Behavior can affect performance and overcome constraints imposedby the fluid medium. Suction performance can be enhanced byproximity to a substrate or by decreasing distance from predatorto prey using various morphological and/or behavioral characteristics.Benthic suction-feeders benefit by the increased strike radiusdue to deflection of water flow when feeding close to a substrate,and perhaps require less accuracy when capturing prey. Suctionand ram-suction-feeding elasmobranchs can also use suction inflowto draw prey to them from a short distance, while ram-feedingsharks must accelerate and overtake the prey. The relationshipbetween feeding strategy and ecology may depend in part on ecological,mechanistic or evolutionary specialization. Mechanistic suction-feedingspecialist elasmobranchs are primarily benthic, while most epibenthicand pelagic elasmobranchs are generalists and use ram, suction,and biting to catch a diversity of prey in various habitats.Some shark species are considered to be ecological specialistsin choosing certain kinds of prey over others. Batoids are evolutionaryspecialists in having a flattened morphology and most are generalistfeeders. Filter-feeding elasmobranchs are ecological, mechanistic,and evolutionary specialists.     

The Effects of Satiation on Strike Mode and Prey Capture Kinematics in the Largemouth bass, Micropterus salmoides

The feeding mechanism and kinematics of prey capture have been studied in many fishes. However, the effects of satiation on the strike mode and prey capture kinematics have never been directly measured. We analyze 12 kinematic variables to determine the effects of satiation on prey capture in five largemouth bass, Micropterus salmoides, by using high speed videography. We also present the first experimental test for modulatory capabilities in response to satiation, by using the ram-suction index. Significant changes in the kinematic variables of maximum lower jaw depression, maximum gape distance, maximum hyoid depression, time to maximum hyoid depression, and time from maximum hyoid depression to recovery were seen with the effects of satiation. Change in the kinematic variables imply a decrease in jaw opening velocity and the magnitude of suction velocity created during repetitive strikes by M. salmoides with increasing satiation. The bass primarily uses a ram strike mode, with some suction bites occasionally. Ram-suction index analyses suggests that M. salmoides does not modulate strike mode in response to satiation. However, the bass modulate prey capture kinematics without altering strike mode with the effects of satiation. Prey capture success decreases in each bass, as the probability of a successful prey capture event becomes lower, with increasing satiation. These findings demonstrate that satiation can have major effects on prey capture kinematics and future studies of feeding kinematics should account for satiation in their analyses.     

Prey Capture in Actinopterygian Fishes: A Review of Suction Feeding Motor Patterns with New Evidence from an Elopomorph Fish, Megalops atlanticus

Suction feeding is recognized as the dominant mode of aquaticprey capture in fishes. While much work has been done identifyingmotor pattern variations of this behavior among diverse groupsof actinopterygian fishes, many ray-finned groups are stillnot represented. Further, the substantial amount of inherentvariation in electromyography makes much of the pioneering workof suction feeding motor patterns in several basal groups insufficientfor evolutionary comparisons. Robust evolutionary comparisonshave identified conserved qualitative traits in the order ofmuscle activation during suction feeding (jaw opening > buccalcavity expansion > jaw closing). However, quantitative traitsof suction motor patterns (i.e., burst durations and relativeonset times) have changed over evolutionary time among actinopterygianfishes. Finally, new motor pattern evidence is presented froma previously neglected group, the Elopomorpha. The results suggestthat future investigations of the muscles influencing lateralexpansion of the mouth cavity and head anatomy may provide valuablenew insights into the evolution of suction feeding motor patternsin ray-finned fishes. In addition, the evidence illustratesthe value of comprehensive EMG surveys of cranial muscle activitiesduring suction feeding behavior.     

Morphological and functional bases of durophagy in the queen triggerfish,Balistes vetula (Pisces,tetraodontiformes)

Tetraodontiform fishes are characterized by jaws specialized for powerful biting and a diet dominated by hard-shelled prey. Strong biting by the oral jaws is an unusual feature among teleosts. We present a functional morphological analysis of the feeding mechanism of a representative tetraodontiform, Balistes vetula. As is typical for the order, long, sharp, strong teeth are mounted on the short, robust jaw bones of B. vetula. The neurocranium and suspensorium are enlarged and strengthened to serve as sites of attachment for the greatly hypertrophied adductor mandibulae muscles. Electromyographic recordings made from 11 cranial muscles during feeding revealed four distinct behaviors in the feeding repertoire of B. vetula. Suction is used effectively to capture soft prey and is associated with a motor pattern similar to that reported for many other teleosts. However, when feeding on hard prey, B. vetula directly bit the prey, exhibiting a motor pattern very different from that of suction feeding. During buccal manipulation, repeated cycles of jaw opening and closing (biting) were coupled with rapid movement of the prey in and out of the mouth. Muscle activity during buccal manipulation was similar to that seen during bite-captures. A blowing behavior was periodically employed during prey handling, as prey were forcefully “spit out” from the mouth, either to reposition them or to separate unwanted material from flesh. The motor pattern used during blowing was distinct from similar behaviors described for other fishes, indicating that this behaviors may be unique to tetraodontiforms. Thus B. vetula combines primitive behaviors and motor patterns (suction feeding and buccal manipulation) with specialized morphology (strong teeth, robust jaws, and hypertrophied adductor muscles) and a novel behavior (blowing) to exploit armored prey such as sea urchins molluscs, and crabs. © 1993 Wiley-Liss, Inc.     

Cranial movements during suction feeding in teleost fishes: Are they modified to enhance suction production?

Suction is produced during prey capture by most teleost fishes. Here, we ask two questions about the functional basis of suction feeding. First, is there variation in the kinematic pattern produced by different species while suction feeding? Second, do species termed 'suction specialists' demonstrate similar modifications to their feeding behavior? We used 10 kinematic variables in a principal component analysis to identify axes of variation among 14 suction feeding teleost species (representing nine families and five orders within the Euteleostei) that demonstrate different feeding habits and habitats. MANOVA and Tukey post hoc tests were used to assess differences among species. Most species clustered together on the principal component axes, suggesting a generalized mechanism that facilitates unidirectional flow. Typically, only one species stood out as 'extreme' on each functional axis, and a species that stood out on one axis did not stand out on others. Only one species, the flatfish Pleuronichthys verticalis, an obligate benthic feeder, demonstrated modifications consistent with enhanced suction production. This species displayed a suite of changes that should enhance suction production, including large hyoid depression, large cranial rotation, and small gape. We suggest that suction performance may be greatest in such obligate benthic feeders because cranial morphology is highly modified and prey are captured from the substrate.     

Foraging and feeding ecology of Platanista: an integrative review

相似文献   

Variability of the fast suction feeding process in Astatotilapia elegans (Teleostei: Cichlidae): a hypothesis of peripheral feedback control

Movement analysis of the 'volume suction' feeding type in Astarotilapia elegans suggests the existence of an inhibiting peripheral feedback control on the fast movements of the head parts, apparently triggered by the food items entering through the mouth aperture. As soon as the prey passes the mouth, rostral expansion of the buccopharyngeal cavity stops. On the basis of a mathematical model and physiological evidence, respectively, visual and chemical perception must probably be excluded as the initial stimulus of the feedback control. The simulation of the hydrodynamic characteristics of the suction flow at the level of the gape reveals sudden changes in the pressure and acceleration waves coupled to the moment of prey uptake. These fluctuations are premised to generate the triggering signal. The possibility of modulation entails re-evaluation of the neuro-motoric preprogamming concept.