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Link to original content: http://pubmed.ncbi.nlm.nih.gov/38172236/
Feeding kinematics of a surgeonfish reveal novel functions and relationships to reef substrata - PubMed Skip to main page content
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. 2024 Jan 3;7(1):13.
doi: 10.1038/s42003-023-05696-z.

Feeding kinematics of a surgeonfish reveal novel functions and relationships to reef substrata

Michalis Mihalitsis  1 , Peter C Wainwright  2
Affiliations

Feeding kinematics of a surgeonfish reveal novel functions and relationships to reef substrata

Michalis Mihalitsis et al. Commun Biol. .

Abstract

Biting to obtain attached benthic prey characterizes a large number of fish species on coral reefs, and is a feeding mode that contributes to important ecosystem functions. We use high-speed video to reveal the mechanisms used by a surgeonfish, Acanthurus leucosternon, to detach algae. After gripping algae in its jaws, the species pulls it by ventrally rotating both the head and the closed jaws, in a novel use of the intra-mandibular joint. These motions remain in the plane of the fish, reducing the use of a lateral head flick to detach the algae. The novel ability to bite and pull algae off the substrate without bending the body laterally minimizes exposure to high water flows, and may be an adaptation to feeding in challenging reef habitats such as the crest and flat. Therefore, our results could potentially represent a key milestone in the evolutionary history of coral reef trophodynamics.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Kinematic profile of the surgeonfish, Acanthurus leucosternon, grazing on benthic algae (see also Supplementary Movies 1, 2).
a Gape distance over time, (b) Jaw rotation through the intra-mandibular joint over time (angle between landmarks FPE). c cranial rotation over time (angle between landmarks AKL), (d) pelvic-neurocranium rotation over time (angle between landmarks IKA), (e) photo of an A. leucosternon with all the landmarks analysed throughout the study, (f) visual representation of how the intra-mandibular joint is used to detach filamentous algae, (g) descriptions of the 5 phases taking place throughout a bite.
Fig. 2
Fig. 2. Mean kinematic profiles of key functional components for all bites (n = 23).
a shows the distance between the tips of the upper and lower jaws (mm). Plots b, c show the mean amount of angular change that takes place between timesteps (anglet- anglet -1). b shows the amount of change in cranial rotation that occurs, (c) shows the amount of change in ventral rotation that occurs in each timestep. Point ranges represent the mean and standard error for all bites, at a given timestep.
Fig. 3
Fig. 3. Pectoral fin kinematics of Acanthurus leucosternon during feeding (see also Supplementary Movie 1) (n = 23).
a Angle between the leading edge, trailing edge, and base of the pectoral fin. Throughout the bite duration, the fish spreads its pectoral fin, resulting in an angle decrease, and (b) pushes the fin anteriorly (protraction). Point ranges represent the mean and standard error for all bites, at a given timestep. The x-axis shows time (ms), whereas the y-axis shows the amount of change relative to the previous timesteps. Values above 0 represent an increase in fin angle (a) or fin protraction (b), whereas values below 0 represent a decrease in fin angle (a) or fin protraction (b).
Fig. 4
Fig. 4. The relationship between algal length and bite kinematics (n = 23).
(a) shows a visual representation of Phase2 and Phase 3, along with the ventral musculature and bone elements (see also Supplemental Movie 1). (b) shows the minimum distance the lower jaw reached during the bite relative to the benthos (mm). (c) shows the odds of detecting the Phase 2 behaviour (i.e., fish pushing away from algae using the benthos). A value of 1 represents the presence of Phase 2 in the bite, whereas a value of 0 represents the absence of it. The odds at which this relationship shifts from zero to one (i.e., odds = 0.5) is at an algal length of 3.1 mm. (d) shows the odds of detecting suction during jaw closure, relative to algal length. A value of 1 represents the presence of suction in the bite, whereas a value of 0 represents the absence of it. The odds at which this relationship shifts from zero to one (i.e., odds = 0.5) is at an algal length of 2.8 mm.
Fig. 5
Fig. 5. Biomechanical interpretation predicting the functional feeding traits increasing the performance of the ventral pull (Phase 2) of Acanthurus leucosternon (n = 14).
a Illustration of A. leucosternon osteology and myology relating to the proposed system, (b) proposed biomechanical interpretation with cranial rotation acting as a motion input, and the ventral side of the fish acting as a motion output system. Letters represent the corresponding landmarks, whereas θ represents the angles between the motion input and output, and ti and tj represent timesteps. c Motion input based on the proposed model against the motion input observed in the landmarked videos (distance covered by L throughout Phase 2). d Amount of change in θ1 observed in videos, against the motion output (θ2) observed in videos. e Ventral expansion (sum of distances EI & IO) predicted by the model, against the ventral expansion observed in videos.
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References

    1. Alexander, R. Functional Design In Fishes (Hutchinson Univ. Library, 1967).
    1. Liem KF. Modulatory multiplicity in the functional repertoire of the feeding mechanism in cichlid fishes. I. Piscivores. J. Morphol. 1978;158:323–360. doi: 10.1002/jmor.1051580305. - DOI - PubMed
    1. Lauder GV. Patterns of evolution in the feeding mechanism of actinopterygian fishes. Am. Zool. 1982;22:275–285. doi: 10.1093/icb/22.2.275. - DOI
    1. Nelson, J. S., Grande, T. C. & Wilson, M. V. Fishes of the World (John Wiley & Sons, 2016).
    1. Schaeffer, B. & Rosen, D. E. Major adaptive levels in the evolution of the actinopterygian feeding mechanism. American Zoologist1, 187–204 (1961).