References of "Frederich, Bruno"
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See detailMeet the Damselfishes
Parmentier, Eric ULg; Frederich, Bruno ULg

in Frederich, Bruno; Parmentier, Eric (Eds.) Biology of Damselfishes (in press)

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See detailCerato-Mandibular Ligament: a Key Trait in Damselfishes?
Olivier, Damien ULg; Frederich, Bruno ULg; Parmentier, Eric ULg

in Frederich, Bruno; Parmentier, Eric (Eds.) Biology of Damselfishes (in press)

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See detailEcomorphology and Iterative Ecological Radiation of Damselfishes
Frederich, Bruno ULg; Cooper, W. James; Aguilar-Medrano, Rosalia

in Frederich, Bruno; Parmentier, Eric (Eds.) Biology of Damselfishes (in press)

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See detailTrophic Ecology of Damselfishes
Frederich, Bruno ULg; Olivier, Damien ULg; Gajdzik, Laura ULg et al

in Frederich, Bruno; Parmentier, Eric (Eds.) Biology of Damselfishes (in press)

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See detailOntogeny and Early Life Stages of Damselfishes
Kavanagh, Kathryn; Frederich, Bruno ULg

in Frederich, Bruno; Parmentier, Eric (Eds.) Biology of Damselfishes (in press)

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See detailBiology of Damselfishes
Frederich, Bruno ULg; Parmentier, Eric ULg

Book published by CRC-Press (in press)

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See detailModular Diversification of the Locomotor System in Damselfishes (Pomacentridae)
Aguilar-Medrano, Rosalia; Frederich, Bruno ULg; Barber, Paul H.

in Journal of Morphology (2016)

As fish move and interact with their aquatic environment by swimming, small morphological variations of the locomotor system can have profound implications on fitness. Damselfishes (Pomacentridae) have ... [more ▼]

As fish move and interact with their aquatic environment by swimming, small morphological variations of the locomotor system can have profound implications on fitness. Damselfishes (Pomacentridae) have inhabited coral reef ecosystems for more than 50 million years. As such, habitat preferences and behavior could significantly constrain the morphology and evolvability of the locomotor system. To test this hypothesis, we used phylogenetic comparative methods on morphometric, ecological and behavioral data. While body elongation represented the primary source of variation in the locomotor system of damselfishes, results also showed a diverse suite of morphological combinations between extreme morphologies. Results show clear associations between behavior, habitat preferences, and morphology, suggesting ecological constraints on shape diversification of the locomotor system. In addition, results indicate that the three modules of the locomotor system are weakly correlated, resulting in versatile and independent characters. These results suggest that Pomacentridae is shape may result from the interaction between (1) integrated parts of morphological variation that main- tain overall swimming ability and (2) relatively independent parts of the morphology that facilitate adaptation and diversification. [less ▲]

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See detailTrophic ecology of the seagrass-inhabiting footballer demoiselle Chrysiptera annulata (Peters, 1855); comparison with three other reef-associated damselfishes
Lepoint, Gilles ULg; Michel, Loïc ULg; Parmentier, Eric ULg et al

in Belgian Journal of Zoology (2016), 146(1), 21-32

Many damselfishes (Pomacentridae) are herbivorous or omnivorous with an important contribution of different kinds of algae in their diet. They display different levels of territoriality and farming ... [more ▼]

Many damselfishes (Pomacentridae) are herbivorous or omnivorous with an important contribution of different kinds of algae in their diet. They display different levels of territoriality and farming behavior, from almost non territorial to monoculture farmers. In addition, few species inhabit seagrass meadows but, presently, none can be considered as seagrass-eating specialists. The footballer demoiselle, Chrysiptera annulata, is found in the seagrass meadows on the reef flat of the Great Reef of Toliara (Madagascar, Mozambique Channel). Regarding this unusual habitat for pomacentrid, this study aimed to answer 3 questions: 1) What is the diet of C. annulata? 2) Do the resources supporting this diet include seagrass? 3) Does its trophic niche overlap those of other sympatric damselfishes (Pomacentrus trilineatus, Chrysiptera unimaculata and Plectroglyphidodon lacrymatus) living in close association with macrophytes or eating algae? Stomach content examination and stable isotope analysis showed that the footballer demoiselle is not a seagrass consumer but is an omnivorous/herbivorous species heavily relying on algal resources and small invertebrates. SIAR, a stable isotope mixing model, indicated it assimilated large amount of turf algae and various benthic or planktonic invertebrates in lower proportions. SIBER metrics pointed out that isotopic niche of the footballer demoiselle partly overlaps the one of its congeneric C. unimaculata, but not those of P. trilineatus and P. lacrymatus. Trophic strategies of C. annulata differed both from farming species such as P. lacrymatus or from less territorial herbivores such as P. trilineatus. Its seagrass meadow habitat on the Great Reef of Toliara allow the conquest of an unusual habitat for damselfishes and could limit competition with C. unimaculata, a species displaying the same territorial behavior and the same isotopic niche but living on the reef itself. [less ▲]

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See detailEffect of evolutionary miniaturization on the tempo and mode of diversification - An example from marine angelfishes
Frederich, Bruno ULg; Santini, Francesco; Konow, Nicolai et al

Conference (2015, October 09)

Evolutionary change in body size is a widespread phenomenon in animals. Numerous studies have highlighted evolutionary miniaturization, referring to the evolution of small body size, in various taxa. As ... [more ▼]

Evolutionary change in body size is a widespread phenomenon in animals. Numerous studies have highlighted evolutionary miniaturization, referring to the evolution of small body size, in various taxa. As other traits shift, decrease in size can be viewed as a morphological novelty that enables colonization of new “adaptive zones” and subsequent diversification (i.e. a “key innovation”). Thus, evolution to small body size is hypothesized to influence lineage, morphological and ecological diversification. Until now, few studies have tested this hypothesis and current supports are mixed. Here, we present a quantitative analysis of the radiation of Pomacanthidae (angelfishes), an iconic coral reef fish family where small taxa, the so called “pygmy angelfishes” of the genus Centropyge, appear to have evolved three-times. If an evolutionary decrease in size has acted as a key innovation during the evolutionary history of Pomacanthidae, we predict that diversification rates would be the highest in clades of pygmy angelfishes. We produced a time-calibrated phylogeny including 67 species, collected ecological data and quantified the body shape of 80 species using geometric morphometrics. Then, we tested the prediction by modelling macroevolutionary dynamics of diversification using the Bayesian Analysis of Macroevolutionary Mixture (BAMM) framework. BAMM results do not support a common macroevolutionary regime for every pigmy angelfish clades. Only the clade Centropyge Xiphypops shows higher rates of lineage and morphological diversification than the other clades of angelfishes. We show that miniaturization has few effects on the rate of diversification. The shifts in the tempo of diversification observed in C. Xiphypops might instead be related to a functional innovation of the feeding apparatus. Using the Pomacanthidae, we illustrate that miniaturization may not be a main factor in triggering increased of diversification rates at the family level. [less ▲]

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See detailStable isotope ratios suggest limited trophic importance of seagrasses for invertebrate consumers from Malagasy tropical polyspecific seagrass meadows
Michel, Loïc ULg; Wang, Haolin; Frederich, Bruno ULg et al

Conference (2015, October 09)

Polyspecific seagrass meadows are of critical ecological importance in tropical coastal zones. These ecosystems provide a wide range of socio-economical services to local populations. Meadows however ... [more ▼]

Polyspecific seagrass meadows are of critical ecological importance in tropical coastal zones. These ecosystems provide a wide range of socio-economical services to local populations. Meadows however undergo multiple threats linked to human activities (increased nutrient input, overfishing, invertebrate overharvesting, etc.). It is currently difficult to assess how seagrass meadows could respond to anthropogenic impacts due to poor knowledge of their functional ecology. Here, stable isotope ratios of carbon, nitrogen and sulfur were used to unravel trophic interactions ruling the food webs associated to seagrass beds of the Toliara Great Reef (SW Madagascar). The contributions of various potential food items (sediment-associated and suspended particulate organic matter, plankton, leaves, roots and epiphytes of 7 seagrasses and thalli of 7 dominant macroalgae) to the diet of 20 invertebrate taxa (one sea urchin, 2 sea stars, 2 sea cucumbers, 5 gastropods including one sea hare, one bivalve, 2 amphipods, one leptostracan, one cumacean 2 hermit crabs and 3 shrimps) were assessed using a Bayesian stable isotope mixing model. Model outputs revealed that important trophic diversity existed among the invertebrate assemblage. In some groups (e.g. hermit crabs and amphipods), resource use by morphologically and taxonomically close taxa was markedly different. Many of the dominant taxa heavily relied on macroalgae for their nutrition. On the other hand, few species apparently consumed seagrass tissues. Moreover, when they did, seagrass generally accounted for a minor portion of the diet only. Overall, our results suggest that seagrass grazing in meadows of the Toliara Great Reef could be lower than in other tropical areas. These discrepancies could be linked with seasonal variation in resource availability or with eutrophication. Higher nutrient load is indeed known to cause ecosystem phase shifts and it may induce diet shift to algivory in some invertebrate consumers. [less ▲]

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See detailTriclosan retardes development of Sheepshead minnow (Cyprinodon variegatus)
Dussenne, Mélanie ULg; Frederich, Bruno ULg; Das, Krishna ULg et al

Conference (2015, October)

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have ... [more ▼]

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have adverse effects on the thyroid system. The study we carried out aims to evaluate the effects of TCS exposure on development of Cyprinodon variegatus, a fish model used in ecotoxicological studies. We investigated the potential effects of TCS on C. variegatus during two key periods; embryonic development and metamorphosis. We exposed eggs and larvae to environmental relevant concentrations. We showed that TCS had no effect on reproduction parameters, such as egg fertility or survival rate of larvae. However, we highlighted the fact that hatching of exposed larvae was delayed of around 6 to 13 hours compared to control embryos. During the larval phase, measurements of THs levels were performed. We showed that TCS affected the typical ontogenic variations of the whole body thyroid hormones concentrations during metamorphosis. As THs are known to control somatic growth and development, we tested the effects of TCS exposure on morphological development. We observed no deformity or malformation, but we revealed a developmental retardation in larvae exposed to TCS, of around 18 to 32 hours. Such a developmental delay had never been highlighted in previous studies on TCS exposed fish. We hypothesize that the disruption of THs homeostasis affects the timing of the start of metamorphosis. As a consequence, exposed larvae showed an extended larval phase compared to the control group. The harmful effects of TCS on physiology and development are a major concern, as marine organisms are constantly exposed to it. Furthermore, strong connections exist between thyroid and reproductive system, which might have deleterious effects on population dynamics. [less ▲]

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See detailImpact of the trophic strategy on the eco-functional diversification of a coral reef fish family
Gajdzik, Laura ULg; Aguilar-Medrano, Rosalia; Parmentier, Eric ULg et al

Conference (2015, September)

The analyses of the role of trophic strategies as promoter or constraint on processes of diversification remain understudied, especially in fish. The Pomacentridae (damselfishes), a species-rich (394 ... [more ▼]

The analyses of the role of trophic strategies as promoter or constraint on processes of diversification remain understudied, especially in fish. The Pomacentridae (damselfishes), a species-rich (394 species) and worldwide distributed reef fish family, include three main trophic guilds: (1) pelagic zooplankton feeders, (2) benthic feeders grazing on turf algae or biting polyps and (3) an intermediate group feeding on zooplankton, small benthic invertebrates and algae. Our study aims to analyze the role of the trophic strategies in the eco-functional diversity of Pomacentridae. Due to its feeding versatility, we hypothesize that the intermediate trophic group is the most successful group in terms of eco-functional diversity through evolutionary time. To target our aim, we compiled detailed dietary, environmental and behavioral data for 201 pomacentrid species, and compared the eco-functional diversity among trophic guilds. Various metrics, such as functional entity (i.e. unique combinations of functional traits) and functional richness revealed that the intermediate trophic group exhibited the lowest diversity. Then, we used time-calibrated phylogenies and comparative methods to evaluate the impact of trophic strategies on the tempo of ecological diversification. Results were consistent and the lowest rate of diversification was found for the intermediate trophic group. Our study shows that a generalist trophic strategy does not promote ecological diversification but being specialized may increase the ability to evolve greater diversity. [less ▲]

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See detailComparison of isotopic turnover dynamics in two different muscles of a coral reef fish during the settlement phase
Gajdzik, Laura ULg; Lepoint, Gilles ULg; Lecchini, David et al

in Scientia Marina (2015), 79(3), 325-333

The temporal variation in carbon and nitrogen isotopic compositions (noted as δ13C and δ15N) was investigated in the convict surgeonfish (Acanthurus triostegus) at Moorea (French Polynesia). Over a period ... [more ▼]

The temporal variation in carbon and nitrogen isotopic compositions (noted as δ13C and δ15N) was investigated in the convict surgeonfish (Acanthurus triostegus) at Moorea (French Polynesia). Over a period of 24 days, juveniles were reared in aquaria and subjected to two different feeding treatments: granules or algae. The dynamics of δ13C and δ15N in two muscles (the adductor mandibulae complex and the epaxial musculature) having different functions were compared. At the end of experiments, a steady-state isotopic system in each muscle tissue was not reached. Especially for the algal treatment, we found different patterns of variation in isotopic compositions over time between the two muscles. The turnovers of δ13C showed opposite trends for each muscle but differences are mitigated by starvation and by the metamorphosis. Our study highlighted that the metabolism of coral reef fish may be subjected to catabolism or anabolism of non-protein precursors at settlement, inducing variation in isotopic compositions that are not linked to diet change. [less ▲]

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See detailThe effects of triclosan exposure in shape changes of sheepshead minnow (Cyprinodon variegatus) during early development and metamorphosis
Schnitzler, Joseph ULg; Frederich, Bruno ULg; Dussenne, Mélanie ULg et al

in Organohalogen Compounds (2015, August)

Thyroid hormones are essential for normal development, and for maintenance of normal physiological functions in vertebrates [1, 2]. In fish, thyroid hormones are involved in the control of osmoregulation ... [more ▼]

Thyroid hormones are essential for normal development, and for maintenance of normal physiological functions in vertebrates [1, 2]. In fish, thyroid hormones are involved in the control of osmoregulation, metabolism, somatic growth and post-hatching metamorphosis [1, 3, 4]. The regulation of thyroid hormone bioavailability in tissues and cells represents a very complex and unique web of feedback systems [2]. In fish and other vertebrates the thyroid cascade involves two components. First, thyroxine (T4) biosynthesis and secretion are largely under central control by the brain–pituitary–thyroid axis [5]. Second, there is the conversion of T4 to its biologically active form 3,5,3-triiodothyronine (T3) and its metabolism and receptor-mediated actions that seems largely to be under peripheral control in extra-thyroidal tissues [6]. The accumulation in the aquatic environment of anthropogenic chemicals, among which are endocrine disrupting chemicals (EDCs) that alter normal hormonal regulation, is having dramatic consequences for humans and wildlife. Numerous chemicals disrupt thyroid homeostasis affecting thyroid hormone (TH) synthesis and transport, and cellular uptake and metabolism [7, 8]. Triclosan (TCS) is a synthetic chlorinated phenolic compound with a generalized use as an antimicrobial and preservative in many personal care and household products [9-11]. As a result of disposal of TCS through sewage systems and insufficient/variable removal by wastewater treatment plants (WWTP) [9], widespread contamination with TCS has been detected in several countries, particularly in aquatic ecosystems, WWTP influents and effluents; sludges and biosolids; surface or ground water; drinking water; and aquatic sediments [9-11]. TCS and its metabolites have been detected in tissues and body fluids of aquatic organisms including fish, revealing they are accumulating in the food chain [9-11] and TCS has also been detected in human blood, breast milk and urine [9-11]. The structural similarity of TCS with THs [9] suggest it may have adverse effects on the thyroid system. However, little is known about the mechanisms by which TCS disrupts the thyroid axis. TCS effects on fish thyroid axis have not been investigated. It is possible, that the TCS toxic effects reported in fish embryos, larvae and adults [9-11] might be caused, at least in part, through its effect on the thyroid system. We determined how TCS affect ontogenic variations of thyroid hormones in developing sheepshead minnow larvae. Knowing that thyroid hormones are involved in somatic growth and post-hatching metamorphosis, we also tested the hypothesis that TCS alter the development of these larvae. To do this, we used landmark-based geometric morphometric methods. These methods allowed us to analyse the pure shape variations of our developing larvae, regardless orientation, position, and size. [less ▲]

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See detailChemical spying in coral reef fish larvae at recruitment
Roux, Natacha; Brooker, Rohan M.; Lecellier, Gaël et al

in Comptes Rendus Biologies (2015), 338

When fish larvae recruit back to a reef, chemical cues are often used to find suitable habitat or to find juvenile or adult conspecifics. We tested if the chemical information used by larvae was ... [more ▼]

When fish larvae recruit back to a reef, chemical cues are often used to find suitable habitat or to find juvenile or adult conspecifics. We tested if the chemical information used by larvae was intentionally produced by juvenile and adult conspecifics already on the reef (communication process) or whether the cues used result from normal biochemical processes with no active involvement by conspecifics (‘‘spying’’ behavior by larvae). Conspecific chemical cues attracted the majority of larvae (four out of the seven species tested); although while some species were equally attracted to cues from adults and juveniles (Chromis viridis, Apogon novemfasciatus), two exhibited greater sensitivity to adult cues (Pomacentrus pavo, Dascyllus aruanus). Our results indicate also that spying cues are those most commonly used by settling fishes (C. viridis, P. pavo, A. novemfasciatus). Only one species (D. aruanus) preferred the odour of conspecifics that had had visual contact with larvae (communication). [less ▲]

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See detailThe evolutionary history of Pomacentridae: key innovation and pattern of diversification
Frederich, Bruno ULg

Scientific conference (2015, April 21)

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See detailUse of C, N and S stable isotope ratios to highlight resource segregation among hermit crabs from tropical seagrass meadows
Michel, Loïc ULg; Frederich, Bruno ULg; Lavitra, Thierry et al

Poster (2015, March 26)

Polyspecific seagrass meadows are ubiquitous features of tropical coastal zones. These ecosystems are of critical ecological importance, and provide a wide range of socio-economical services to local ... [more ▼]

Polyspecific seagrass meadows are ubiquitous features of tropical coastal zones. These ecosystems are of critical ecological importance, and provide a wide range of socio-economical services to local populations. Meadows however undergo multiple threats linked to human activities (increased nutrient input, overfishing, invertebrate overharvesting, etc.). It is currently hard to assess how seagrass meadows could respond to anthropogenic impacts due to poor knowledge of their functional ecology. In an effort to unravel trophic interactions ruling the food webs associated to seagrass beds of the Toliara Great Reef (SW Madagascar), we studied resource segregation between two common Diogenidae hermit crabs (Dardanus scutellatus and Ciliopagurus tricolor) using stable isotope ratios. C, N and S stable isotope ratios of bulk muscle tissue were measured via CF-EA-IRMS (Elementar Vario MicroCube EA coupled to an Isoprime 100 MS). Interspecific differences were noted in isotopic composition of carbon (δ13C = -12.22 ± 1.73 ‰ for D. scutellatus, δ13C = -14.55 ± 0.73 ‰ for C. tricolor), nitrogen (δ15N = 4.73 ± 0.53 ‰ for D. scutellatus, δ15N = 5.20 ± 0.61 ‰ for C. tricolor) and sulfur (δ34S = 14.08 ± 2.32 ‰ for D. scutellatus, δ34S = 16.73 ± 1.49 ‰ for C. tricolor), suggesting that the two species do not feed on the same items. In addition, SIBER (Stable Isotope Bayesian Ellipses in R) modeling based on C and N data clearly showed that no overlap was present in the core isotopic niches of the two species. It also indicated that the isotopic niche of D. scutellatus was greater than the one of C. tricolor, implying that the former feeds on a greater number of items than the latter. While hermit crabs are generally considered as omnivorous species, this study highlighted differences in the foraging ecology of D. scutellatus and C. tricolor. These differences could help to limit competition for food between these two species, and facilitate their coexistence in Malagasy seagrass beds. [less ▲]

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See detailA morphological novelty for feeding and sound production in the yellowtail clownfish
Olivier, Damien ULg; Frederich, Bruno ULg; Herrel, Anthony et al

in Journal of Experimental Zoology. Part A, Comparative Experimental Biology (2015), 323A

The yellowtail clownfish Amphiprion clarkii is able to close its mouth very quickly by means of the cerato-mandibular (c-md) ligament, a synapomorphic trait of Pomacentridae joining the hyoid bar to the ... [more ▼]

The yellowtail clownfish Amphiprion clarkii is able to close its mouth very quickly by means of the cerato-mandibular (c-md) ligament, a synapomorphic trait of Pomacentridae joining the hyoid bar to the medial part of the lower jaw. This fast closure induces tooth collision, thus producing sounds that the clownfish uses during agonistic behaviors. To investigate whether this rapid jaw movement is also used during feeding, we analyzed the kinematics of sound production and feeding. Sound production, feeding on live planktonic prey, and feeding on food attached to tweezers were filmed with a high-speed camera. Three kinds of kinematic patterns were detected and were associated with the two different types of food presented: one performed to catch planktonic prey (PP), and two (called B-1 and B-2) to bite attached food items. The kinematic pattern of B-2 is similar to that observed during sound production (SP) and the transection of the c-md ligament highlights that sound production and biting-2 motions are dependent on this morphological trait. Our data show that the c-md ligament in addition to its role in sound production allows duplication of the mouth closing mechanism during feeding. This highlights the key role played by the c-md ligament in sound production and feeding on attached prey. [less ▲]

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See detailThe cerato-mandibular ligament: an innovation for sound production and feeding in damselfishes (Pomacentridae).
Olivier, Damien ULg; Frederich, Bruno ULg; Spanopoulos-Zarco, Milton et al

Conference (2014, December 12)

The success of a taxonomic group can be promoted by a key character that allows the group to interact with its environment in a different way and to potentially occupy new niches. The Pomacentridae ... [more ▼]

The success of a taxonomic group can be promoted by a key character that allows the group to interact with its environment in a different way and to potentially occupy new niches. The Pomacentridae possess a synapomorphic trait, the cerato-mandibular (c-md) ligament, which joins the hyoid bar to the inner part of the lower jaw. It has previously been shown that this ligament is a key trait in communication in damselfishes because it enables them to slam the oral jaws shut causing teeth collision and sound production. This specific behavior of mouth closing could, however, also be used for other tasks, such as feeding. Many territorial damselfishes are referred to as farmers, due to their ability to manage algal crops on which they feed. This study hypothesizes that the c-md ligament provides an advantage for grazing filamentous algae, and should thus be considered a key trait for farming behavior. The kinematic patterns associated with sound production and biting filamentous algae or attached animal prey are all based on the same mechanism and are associated with a slam of the oral jaws. We observed that transection of the c-md ligaments makes the fish unable to perform such actions. This study shows that the c-md ligament is a key trait both for sound production and for grazing activities in damselfishes. The buccal jaw slam enables the fish to perform accurate strikes on small filamentous algae. This kind of bite probably plays a major role in farming activity and allows grazing damselfishes to occupy distinct niches, possibly increasing their competitive evolutionary success. [less ▲]

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