References of "Vandewalle, Pierre"
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See detailProduction de sons chez les Carapidae: un nouveau type de mécanisme
Parmentier, Eric ULg; Lagardère, Jean-Paul; Braquenier, Jean-Baptiste ULg et al

Conference (2006)

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See detailEcomorphology of the Pomacentridae skull: a landmark-based geometric morphometric approach
Pilet, Arnaud; Frederich, Bruno ULg; Parmentier, Eric ULg et al

Poster (2005, October)

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See detailGeographical variation in sound production in the anemonefish Amphiprion akallopisos
Parmentier, Eric ULg; Lagardere, J. P.; Vandewalle, Pierre ULg et al

in Proceedings of the Royal Society B-Biological Sciences (2005), 272(1573), 1697-1703

Because of pelagic-larval dispersal, coral-reef fishes are distributed widely with minimal genetic differentiation between populations. Amphiprion akallopisos, a clownfish that uses sound production to ... [more ▼]

Because of pelagic-larval dispersal, coral-reef fishes are distributed widely with minimal genetic differentiation between populations. Amphiprion akallopisos, a clownfish that uses sound production to defend its anemone territory, has a wide but disjunct distribution in the Indian Ocean. We compared sounds produced by these fishes from populations in Madagascar and Indonesia, a distance of 6500 km. Differentiation of agonistic calls into distinct types indicates a complexity not previously recorded in fishes' acoustic communication. Moreover, various acoustic parameters, including peak frequency, pulse duration, number of peaks per pulse, differed between the two populations. The geographic comparison is the first to demonstrate 'dialects' in a marine fish species, and these differences in sound parameters suggest genetic divergence between these two populations. These results highlight the possible approach for investigating the role of sounds in fish behaviour in reproductive divergence and speciation. [less ▲]

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See detailEarly development of the head skeleton in Brycon moorei (Pisces, Ostariophysi, Characidae)
Vandewalle, Pierre ULg; Germeau, G.; Besancenet, P. et al

in Journal of Fish Biology (2005), 66(4), 996-1024

At hatching (15 h post fertilization), Brycon moorei possesses no skeletal structure. Thereafter, development is very rapid. The first oral teeth appear no later than 3 It post-hatching, but they remain ... [more ▼]

At hatching (15 h post fertilization), Brycon moorei possesses no skeletal structure. Thereafter, development is very rapid. The first oral teeth appear no later than 3 It post-hatching, but they remain covered with epithelium until c. 45 h. At 7 h, the trabecular bars and part of the cartilaginous visceral arches are visible and at 15 It, the dentaries and premaxillaries are present. At 25 h, i.e. the onset of piscivory and cannibalism (the yolk sac is only fully resorbed after 36 h), the oral teeth are fully developed, the first pharyngeal teeth are formed, and some head movements already appear synchronized, but the mouth cavity is not completely isolated from the neurocranium by bony structures. Thereafter, no new buccal or pharyngeal bony structure is visible until 45 h, when the maxilla and opercula appear, along with a new type of cannibalistic behaviour. Cartilage resorptions also start at 45 It, but with no concomitant replacement by formation of calcified structures. Later, development gradually becomes similar to that of many previously studied teleosts. The developmental pattern of B. moorei is thus extremely rapid in comparison with other teleosts, i.e. it prioritizes feeding structures that permit the expression of piscivory at a very early age. The uniqueness of this pattern is discussed in relation to ecological constraints on early feeding and fast growth. (c) 2005 The Fisheries Society of the British Isles. [less ▲]

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See detailFurther insight on carapid - holothuroid relationships
Parmentier, Eric ULg; Vandewalle, Pierre ULg

in Marine Biology (2005), 146(3), 455-465

Carapidae (or pearlfish) are eel-like fishes that live inside different invertebrates, such as holothurians, sea stars, or bivalves. Those of the genus Carapus are commensal and use their host as a ... [more ▼]

Carapidae (or pearlfish) are eel-like fishes that live inside different invertebrates, such as holothurians, sea stars, or bivalves. Those of the genus Carapus are commensal and use their host as a shelter, while Encheliophis species are parasitic and eat the host's gonads. In areas where they live in sympatry, C. boraborensis, C. homei, C. mourlani and E. gracilis are able to inhabit the same host species. Infestation is considered as monospecific when several conspecifics are observed in the same host. However, many aspects of this particular relation remain obscure, e.g. communication between carapids and the defence systems of the different protagonists (carapids and hosts). Experiments have been conducted in the field and laboratory to investigate several aspects of the carapids' relationships with their hosts. Sampling carried out in the Bay of Opunohu (Moorea, French Polynesia) determined the sex ratio of C. boraborensis (3:1) and C. homei (1:1) and their distribution rate within different Echinodermata. Our study showed that neither species was capable of determining whether a heterospecific already occupied a sea cucumber or not. They were, however, able to locate the sea cucumber's cloaca, due to the excurrent resulting from respiration. The sea cucumber's defence system (Cuverian tubules) minimises predator attacks, but is not effective against carapid intrusion. The Carapidae defence system is twofold. Due to a passive system related to the sea cucumber's low cloacal position, the Cuverian tubules are not expelled when fish enter the cloaca. Moreover, carapids resist sea cucumber toxins better than other reef fish. Their increased resistance might be related to their gills rather than to their mucus coating; however, the latter may assist the fish in resisting the sticky substances emitted by the Cuverian tubules. [less ▲]

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See detailTemporal variability of settlement in Carapidae larvae (Teleostei) at Rangiroa atoll
Colleye, Orphal ULg; Brié, Christophe; Vandewalle, Pierre ULg et al

Poster (2005)

Carapidae (or pearlfish) are eel-like fishes living inside different invertebrates, such as holothurians, sea stars or bivalves. In some Polynesian areas where they live in sympatry, several species ... [more ▼]

Carapidae (or pearlfish) are eel-like fishes living inside different invertebrates, such as holothurians, sea stars or bivalves. In some Polynesian areas where they live in sympatry, several species (Carapus homei, Carapus mourlani, Carapus boraborensis and Encheliophis gracilis) are able to inhabit the same host species. The heterospecific infestation rate is very rare, suggesting that the four species can compete for their hosts. Some differences in settlement period, breeding period and in pelagic larval duration (PLD) could allow better characterisation of the life history of each species. More than 700 larvae were collected during an entire year on the Rangiroa atoll (French Polynesia). Each species was identified; their settlement pattern was examined and their PLD was deduced from otolith (sagittae) increments. In the four collected species, the settlement pattern differed: C. homei and C. mourlani settle on the reef during the entire year, and show an asynchronous and diffuse breeding cycle. C. boraborensis and E. gracilis have a shorter settlement period which could be compatible with breeding synchronisation. As most reef fishes, Carapidae larvae mainly settle during moonless nights. Moreover, each species presents some plasticity, allowing it to settle on the reef under suitable conditions. [less ▲]

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See detailOntogenic and ecological control of metamorphosis onset in a carapid fish, Carapus homei: Experimental evidence from vertebra and otolith comparisons
Parmentier, Eric ULg; Lecchini, David; Lagardere, Françoise et al

in Journal of Experimental Zoology. Part A, Comparative Experimental Biology (2004), 301A(8), 617-628

In Carapus homei, reef colonisation is associated with a penetration inside a sea cucumber followed by heavy transformations during which the length of the fish is reduced by 60%. By comparing vertebral ... [more ▼]

In Carapus homei, reef colonisation is associated with a penetration inside a sea cucumber followed by heavy transformations during which the length of the fish is reduced by 60%. By comparing vertebral axis to otolith ontogenetic changes, this study aimed (i) to specify the events linked to metamorphosis, and (ii) to establish to what extent these fish have the ability to delay it. Different larvae of C. homei were caught when settling on the reef and kept in different experimental conditions for at least 7 days and up to 21 days: darkness or natural light conditions, presence of sea cucumber or not, and food deprivation or not. Whatever the nutritional condition, a period of darkness seems sufficient to initiate metamorphosis. Twenty-one days in natural light conditions delayed metamorphosis, whereas the whole metamorphosis process is the fastest (15 days) for larvae living in sea cucumbers. Whether the metamorphosis was initiated or not, otoliths were modified with the formation of a transition zone, whose structure varied depending on the experimental conditions. At day 21, larvae maintained in darkness had an otolith transition zone with more increments (around 80), albeit wider than those (more or less 21) of individuals kept under natural lighting. These differences in otolith growth could indicate an increased incorporation rate of released metabolites by metamorphosing larvae. However, the presence of a transition zone in delayed-metamorphosis larvae suggests that these otolith changes record the endogenously-induced onset of metamorphosis, whereas body transformations seem to be modulated by the environmental conditions of settlement. (C) 2004 Wiley-Liss, Inc. [less ▲]

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See detailRemodelling of the vertebral axis during metamorphic shrinkage in the pearlfish
Parmentier, Eric ULg; Lecchini, David; Vandewalle, Pierre ULg

in Journal of Fish Biology (2004), 64(1), 159-169

Body shortening was observed in the pearlfish Carapus homei during metamorphosis. The tenuis larva at first possessed a suite of osseous vertebral bodies of similar length. The reduction in both the ... [more ▼]

Body shortening was observed in the pearlfish Carapus homei during metamorphosis. The tenuis larva at first possessed a suite of osseous vertebral bodies of similar length. The reduction in both the number and size of vertebrae followed increasing decalcification, degeneration of organic tissue and shortening. This involved a complete degradation and disappearance of the caudal tip vertebrae, and there was a reduction in the size of most of the remaining vertebrae. The further development of the vertebrae began with ossification of the neural and haemal arches before that of the vertebral body. This second part of the development followed a gradient: a gradual decreases towards the caudal tip in the size of the vertebrae and their completeness. (C) 2004 The Fisheries Society of the British Isles. [less ▲]

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See detailCharacterization of the primary sonic muscles in Carapus acus (Carapidae): a multidisciplinary approach
Parmentier, Eric ULg; Gennotte, Vincent ULg; Focant, Bruno et al

in Proceedings of the Royal Society B : Biological Sciences (2003), 270(1530), 2301-2308

Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic ... [more ▼]

Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic muscles and compare them with epaxial muscles in Carapus acus. Sonic fibres are thicker than red and thinner than white epaxial fibres, and sonic fibres and myofibrils exhibit an unusual helicoidal organization: the myofibrils of the centre are in a straight line whereas they are more and more twisted towards the periphery. Sonic muscles have both features of red (numerous mitochondria, high glycogen content) and white (alkali-stable ATPase) fibres. They differ also in the isoforms of the light chain (LC3) and heavy chain (HC), in having T tubules at both the Z-line and the A–I junction and in a unique parvalbumin isoform (PAI) that may aid relaxation. All these features lead to the expression of two assumptions about sound generation: the sonic muscle should be able to perform fast and powerful contractions that provoke the forward movement of the forepart of the swim bladder and the stretching and ‘flapping’ of the swim bladder fenestra; the helicoidal organization allows progressive drawing of the swim bladder fenestra which emits a sound when rapidly released in a spring-like manner. [less ▲]

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See detailSound-producing mechanisms and recordings in Carapini species (Teleostei, Pisces)
Parmentier, Eric ULg; Vandewalle, Pierre ULg; Lagardere, Jean-Pierre

in Journal of Comparative Physiology A-Neuroethology Sensory Neural and Behavioral Physiology (2003), 189(4), 283-292

Carapus boraborensis, C. homei and Encheliophis gracilis are three species of Carapidae that display the ability to penetrate and reside in the holothurian Bohadschia argus. This study describes both the ... [more ▼]

Carapus boraborensis, C. homei and Encheliophis gracilis are three species of Carapidae that display the ability to penetrate and reside in the holothurian Bohadschia argus. This study describes both the particular morphology of the sound-producing structures and, for the first time, the sounds produced by each species. The study of the structures composing the sound-producing system seems to indicate that the action made by the primary sonic muscles (i.e. the pulling and releasing of the front of the swim bladder) might be responsible for the sound emissions of these three species by provoking a vibration of a thinner zone in front of the swim bladder (swimbladder fenestra). The sounds were only emitted and recorded when several individuals of the same species were inside the same sea cucumber. They were composed of serially repeated knocks and were heard as drum beats or drum rolls. Their specific differences were mainly defined as variations in the timing or grouping of the knocking sounds. The recordings of these sound productions demonstrate a vocal ability for the three species, linked with the presence of particular organs associated with sound production. Moreover, the ecological significance of the sounds and of the sound apparatus system is discussed. [less ▲]

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See detailMorphological adaptations of Pearlfish (Carapidae) to their various habitats
Parmentier, Eric ULg; Vandewalle, Pierre ULg

in Kapoor, B. G.; Val, Aldaberto Luis (Eds.) Fish adaptations (2003)

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See detailMorphology, development and evolution of the weberian apparatus in catfishes
Chardon, Michel ULg; Parmentier, Eric ULg; Vandewalle, Pierre ULg

in Kapoor, B. G.; Arratia, G.; Chardon, Michel (Eds.) et al Catfishes (2003)

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See detailRelationships between inner ear and sagitta growth during ontogenesis of three Carapini species, and consequences of life-history events on the otolith microstructure
Parmentier, Eric ULg; Lagardère, Françoise; Vandewalle, Pierre ULg

in Marine Biology (2002), 141(3), 491-501

Three species of Carapidae have in common a tenuis larval stage, during which they settle in the lagoon and take refuge in the same species of holothurold. From the juvenile stage, Carapus homei and C ... [more ▼]

Three species of Carapidae have in common a tenuis larval stage, during which they settle in the lagoon and take refuge in the same species of holothurold. From the juvenile stage, Carapus homei and C. boraborensis are commensal, whereas Encheliophis gracilis is parasitic. The aims of this study were to analyse to what extent the ontogenctic changes of the otic capsule affected the shape of the inner ear and how environmental cues, due to the above-mentioned life history and the style, could influence the structure of the sagitta. Sagittal sections revealed a three-dimensional asymmetry with a nucleus close to the proximal surface. Observations of the growth axis of the sagitta suggest it has a morphogenetic impact on the otic cavity. Each sagitta contains three main zones related to the life stages of the fish. Bands and checks were observed in the third zone in C. homei and C. boraborensis, but this pattern was less discernible in E. gracilis. These structural differences in zone 3 could be related to the commensal and parasitic life styles of these fishes. Further studies dealing with otosac features and otolith functions are suggested. [less ▲]

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See detailParticularities of the bucco-pharyngeal apparatus in Zenarchopterus kampeni (Pisces : Hemiramphidae) and their probable significance in feeding
Vandewalle, Pierre ULg; Lambert, Vincianne; Parmentier, Eric ULg

in Belgian Journal of Zoology (2002), 132(2), 125-132

The present study shows several new anatomical particularities of the buccal and pharyngeal parts of the halfbeak Zenarchopterus kampeni. The upper buccal jaw consists of premaxillaries and maxillaries ... [more ▼]

The present study shows several new anatomical particularities of the buccal and pharyngeal parts of the halfbeak Zenarchopterus kampeni. The upper buccal jaw consists of premaxillaries and maxillaries tightly joined by ligaments. A 10degrees lowering of the mandible leads to a 30degrees elevation of the upper jaw. The adductor mandibulae is reduced to bundles A(2) and Aomega. As in the Labridae, the lower pharyngeal jaw articulates with the scapular girdle. The upper pharyngeal jaw consists of distinct second pharyngobranchials followed by the third pharyngobranchials fused into a powerful posterior component. This part fits into and slides along a longitudinal ventral gutter of the neuroranium, thanks not only to the dorsal retractor muscles but also to specific retractors of the second pharyngobranchials. The power and dentition of the pharyngeal parts contrasts with the fragility of the buccal elements. [less ▲]

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See detailIdentification of tenuis of four French Polynesian Carapini (Carapidae : Teleostei)
Parmentier, Eric ULg; Lo-Yat, A.; Vandewalle, Pierre ULg

in Marine Biology (2002), 140(3), 633-638

Four species of adult Carapini (Carapidae) occur on Polynesian coral reefs: Encheliophis gracilis, Carapus boraborensis, C. homei and C. mourlani. Samples collected in Rangiroa and Moorea allowed us to ... [more ▼]

Four species of adult Carapini (Carapidae) occur on Polynesian coral reefs: Encheliophis gracilis, Carapus boraborensis, C. homei and C. mourlani. Samples collected in Rangiroa and Moorea allowed us to obtain different tenuis (larvae) during their settlement phases or directly inside their hosts. These were separated into four lots on the basis of a combination of pigmentation, meristic, morphological, dental and otolith (sagittae) features. Comparison of these characters with those of the adults allows, for the first time, taxonomic identification of these tenuis-stage larvae. [less ▲]

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