A possible relationship between aspects of dentition and feeding in the centrarchid and anabantoid fishes

Certain components of dentition — teeth on the third basibranchial in the Centrarchidae and on the parasphenoid in the anabantoids (sensu lato) — are very rare elsewhere in higher teleostean fishes. Though these basibranchial and parasphenoid teeth in the two fish groups are on opposite sides of the oral cavity, it is hypothesized that they both developed as adaptations for gripping a particular category of food items, namely strong-clawed, hard-shelled, active animals that, once within the oral cavity, would try to crawl out again. A corollary to this hypothesis is that higher teleosts with extensive dentition in the central part of the oral cavity have a grasping jaw bite, which, unlike a piercing, shearing, or crushing jaw bite, does not necessarily kill the prey that is taken into the oral cavity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42630/1/10641_2004_Article_BF00005147.pd

Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record

Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernández, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin

Aquatic suction feeding dynamics: insights from computational modelling

Aquatic suction feeding in vertebrates involves extremely unsteady flow, externally as well as internally of the expanding mouth cavity. Consequently, studying the hydrodynamics involved in this process is a challenging research area, where experimental studies and mathematical models gradually aid our understanding of how suction feeding works mechanically. Especially for flow patterns inside the mouth cavity, our current knowledge is almost entirely based on modelling studies. In the present paper, we critically discuss some of the assumptions and limitations of previous analytical models of suction feeding using computational fluid dynamics

Anterior-to-posterior wave of buccal expansion in suction feeding fishes is critical for optimizing fluid flow velocity profile

In fishes that employ suction feeding, coordinating the timing of peak flow velocity with mouth opening is likely to be an important feature of prey capture success because this will allow the highest forces to be exerted on prey items when the jaws are fully extended and the flow field is at its largest. Although it has long been known that kinematics of buccal expansion in feeding fishes are characterized by an anterior-to-posterior wave of expansion, this pattern has not been incorporated in most previous computational models of suction feeding. As a consequence, these models have failed to correctly predict the timing of peak flow velocity, which according to the currently available empirical data should occur around the time of peak gape. In this study, we use a simple fluid dynamic model to demonstrate that the inclusion of an anterior-to-posterior wave of buccal expansion can correctly reproduce the empirically determined flow velocity profile, although only under very constrained conditions, whereas models that do not allow this wave of expansion inevitably predict peak velocity earlier in the strike, when the gape is less than half of its maximum. The conditions that are required to produce a realistic velocity profile are as follows: (i) a relatively long time lag between mouth opening and expansion of the more posterior parts of the mouth, (ii) a short anterior portion of the mouth relative to more posterior sections, and (iii) a pattern of movement that begins slowly and then rapidly accelerates. Greater maximum velocities were generated in simulations without the anterior-to-posterior wave of expansion, suggesting a trade-off between maximizing fluid speed and coordination of peak fluid speed with peak gape

Rapid pivot feeding in pipefish: flow effects on prey and evaluation of simple dynamic modelling via computational fluid dynamics

Most theoretical models of unsteady aquatic movement in organisms assume that including steady-state drag force and added mass approximates the hydrodynamic force exerted on an organism's body. However, animals often perform explosively quick movements where high accelerations are realized in a few milliseconds and are followed closely by rapid decelerations. For such highly unsteady movements, the accuracy of this modelling approach may be limited. This type of movement can be found during pivot feeding in pipefish that abruptly rotate their head and snout towards prey. We used computational fluid dynamics (CFD) to validate a simple analytical model of cranial rotation in pipefish. CFD simulations also allowed us to assess prey displacement by head rotation. CFD showed that the analytical model accurately calculates the forces exerted on the pipefish. Although the initial phase of acceleration changes the flow patterns during the subsequent deceleration phase, the accuracy of the analytical model was not reduced during this deceleration phase. Our analysis also showed that prey are left approximately stationary despite the quickly approaching pipefish snout. This suggests that pivot-feeding fish need little or no suction to compensate for the effects of the flow induced by cranial rotation

Hydrodynamic modelling of aquatic suction performance and intra-oral pressures: limitations for comparative studies

The magnitude of sub-ambient pressure inside the bucco-pharyngeal cavity of aquatic animals is generally considered a valuable metric of suction feeding performance. However, these pressures do not provide a direct indication of the effect of the suction act on the movement of the prey item. Especially when comparing suction performance of animals with differences in the shape of the expanding bucco-pharyngeal cavity, the link between speed of expansion, water velocity, force exerted on the prey and intra-oral pressure remains obscure. By using mathematical models of the heads of catfishes, a morphologically diverse group of aquatic suction feeders, these relationships were tested. The kinematics of these models were fine-tuned to transport a given prey towards the mouth in the same way. Next, the calculated pressures inside these models were compared. The results show that no simple relationship exists between the amount of generated sub-ambient pressure and the force exerted on the prey during suction feeding, unless animals of the same species are compared. Therefore, for evaluating suction performance in aquatic animals in future studies, the focus should be on the flow velocities in front of the mouth, for which a direct relationship exists with the hydrodynamic force exerted on prey