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The objective of this thesis is to revise the taxonomy of the French species of polychaetes belonging to the five families of Terebellidae sensu lato (Polycirridae, Telothelepodidae, Terebellidae, Thelepodidae and Trichobranchidae). These spaghetti worms are characterised by the presence of multiple non-retractable buccal tentacles used for feeding (deposit feeders).The specimens studied in this thesis were collected during different research and observation programs or specific samplings carried out by scientists in the different French laboratories. Type materials from the Museum National d’Histoire Naturelle were also loaned.This study is at the heart of the “Spaghetti Project”, project involving benthic taxonomists from French marine stations (RESOMAR network).French coastal waters are well-known areas, studied for several centuries by early taxonomists and benthic ecologists. However, studying numerous spaghetti worms with new tools, like scanning electron microscope and molecular analysis, has revealed the existence of 31 species new for science.These species have probably “always” been present along the French coasts but misidentified for decades. Several reasons can explain this situation. First, these worms are relatively challenging to identify because of diagnostic characters requiring detailed examination and modern tools. Secondly, most of the European species were described in the 18 and 19th centuries. Taxonomic standards at that time were very different with very brief descriptions and illustrations (when present) of poor quality. Moreover, type material was rarely deposited in a museum collection, and when deposited subsequently often lost or damaged, preventing any comparison with specimens newly collected. Finally, until 1980s, there was a wide perception that widespread species were very common among polychaetes. Studying these so-called “cosmopolitan” species in detail reveals the existence of numerous cryptic species in different parts of the world, in France in particular., Cette thèse a pour objectif de réviser la taxonomie des espèces françaises d’annélides polychètes appartenant aux cinq familles des Terebellidae sensu lato (Polycirridae, Telothelepodidae, Terebellidae sensu stricto, Thelepodidae et Trichobranchidae). Ces vers spaghetti sont caractérisés par la présence de nombreux tentacules buccaux non rétractables servant à leur nutrition et leur assurant un régime déposivore.Les individus étudiés dans le cadre de cette thèse ont été prélevés lors de différents projets de recherche et d’observation menés par les équipes hébergées dans les stations marines françaises, mais également lors d’échantillonnages spécifiques. Des matériels types, archivés au Museum National d’Histoire Naturelle, ont également été empruntés. Cette étude est au centre du « Spaghetti Project », projet collaboratif impliquant les taxonomistes benthiques des différentes stations marines françaises (RESOMAR, RESeau des Stations et Observatoires MARins).Les eaux côtières françaises sont des zones étudiées depuis plusieurs siècles par les premiers taxinomistes et les écologistes benthiques. Cependant, l’étude de nombreux spécimens de vers spaghetti à l’aide de nouveaux outils, comme la microscopie électronique à balayage ou l’analyses moléculaire, a révélé l’existence de 31 espèces nouvelles pour la science.Ces espèces ont probablement « toujours » été présentes le long des côtes mais mal identifiées pendant des décennies. Plusieurs raisons peuvent expliquer ces lacunes. La première est que ces vers sont extrêmement complexes à identifier car les caractères morphologiques nécessitent des observations pointues et des outils modernes. Deuxièmement, la plupart des espèces européennes ont été décrites aux 18ème et 19ème siècles. Les standards taxonomiques de l’époque étaient très différents, avec des descriptions très brèves et des illustrations (quand elles étaient présentes) de qualité médiocre. De plus, les matériels types étaient rarement déposés dans une collection d’un muséum, et quand ils l’étaient ont malheureusement souvent été endommagés ou perdus, empêchant des comparaisons avec des spécimens nouvellement collectés. Enfin, il y a eu jusque dans les années 1980, une idée largement répandue selon laquelle les espèces de polychètes à large distribution étaient très communes. L’étude de ces espèces soi-disant cosmopolites a révélé l’existence de nombreuses espèces cryptiques dans le monde entier en général, et en France en particulier.

The polychaetes communities structure and functioning of the Cap Bon peninsula (Northeast coast of Tunisia), were analyzed from 52 stations from Sidi Daoud to Menzel Horr. The faunistic study reveals the presence of 238 polychaetes species among which 86 records are newly reported for the Tunisian coasts. The total number of polychaetes listed in Tunisia rises to 375 species. The polychaete community structure at the sites was examined by multivariate methods. five main polychaetes communities were identified in the study area, the sandy sediment community (SS), the muddy sediments community (SV), the coarse sediment community (SG), the fine-muddy sediment community (SFV) and the Heterogeneous sediments community (HS). These communities are distributed mainly according to the particle size sediment and the Sampling depth. The SS community characterized by the dominance of Eunice vittata and the SG community dominated by Aponuphis fauveli showed the greatest number of species and diversity. Aponuphis fauveli, Eunice vittata and Protodorvillea kefersteini were the dominant species in the area. The particle size sediment and the sampling depth are also the main factors that govern the seasonal distribution of the polychaete communities in the Sidi Daoud-Ras Lahmer zone. Monitoring reveals that summer and winter seasons showed the highest values of density and diversity. The Cap Bon peninsula as a coastal zone is exposed to increasing anthropogenic activities, such as urban and industrial discharges and terrigenous several wadis. Polychaetes which react differently to this situation constitute an effective biological tool to detect signs of environmental degradation. Ecological groups and the AMBI index (Azti Marine Biotic Index) were used with biodiversity indices in order to evaluate the ecological quality of the Cap Bon peninsula. The general status of the study area is generally satisfactory and slightly polluted, except the inner part of the Sidi Daoud bay (station D and E) where we recorded an extremely polluted status. The first estimate of the genetic diversity populations of Hyalinoecia tubicola and Aponuphis bilineata based on the RAPD data analysis showed that these two species seem to be genetically similar. La structure et le fonctionnement des communautés d’Annélides polychètes de la péninsule du Cap Bon (côte Nord-Est de la Tunisie), ont été analysés à partir de 52 stations réparties de la région de Sidi Daoud à Menzel Horr. L’étude faunistique révèle la présence de 238 espèces de polychètes dont 86 sont nouvellement signalées pour les côtes Tunisiennes. Le nombre total des Polychètes recensés en Tunisie s’élève alors à 375 espèces. Les analyses multivariées de la composition faunistique des stations a permis d’identifier cinq principaux peuplements de polychètes dans le secteur étudié; le peuplement des sédiments sableux (SS), le peuplement des sédiments vaseux (SV), le peuplement des sédiments grossiers (SG), le peuplement des sédiments fins à envasés (SFV) et le peuplement des sédiments Hétérogènes (SH). Ces peuplements se répartissent essentiellement en fonction de la granulométrie du sédiment et de la bathymétrie des stations prospectées. Le peuplement des SS à Eunice vittata et celui des SG à Aponuphis fauveli sont les plus diversifiés avec la dominance des trois espèces Aponuphis fauveli, Eunice vittata et Protodorvillea kefersteini. La granulométrie du sédiment et la bathymétrie sont aussi les facteurs qui régissent la distribution saisonnière des communautés de polychète révélées dans le secteur Sidi Daoud-Ras Lahmer. Le suivi saisonnier révèle que les saisons estivale et hivernale montrent les valeurs de densités et de diversité les plus élevées. En tant que zone côtière, la péninsule du Cap Bon est exposée aux activités anthropiques croissantes, telles que les rejets urbains et industriels et les apports terrigènes de plusieurs oueds. Les Annélides polychètes, qui réagissent différemment face à cette situation, constituent un outil biologique efficace pour déceler les signes de dégradation du milieu. Le modèle des groupes écologiques et l’indice AMBI (Azti Marine Biotic Index) ont été employés conjointement avec les indices de biodiversité pour évaluer l’état écologique général dans la péninsule. Cet état apparaît globalement satisfaisant et légèrement pollué, à l’exception de la région de Sidi Daoud où on enregistre un état extrêmement pollué dans la partie interne de la baie (station D et E). La première estimation de la diversité génétique des populations de Hyalinoecia tubicola et Aponuphis bilineata, basée sur des analyses de données RAPD, montre que ces deux dernières semblent génétiquement voisines. Submitted Peninsula Community structure Seasonal study

Three species of gregarines were found in specimens of the annelid polychaete Marphysa sanguinea collected in the Lake of Tunis: Bhatiella marphysae Setna, 1931, described from Marphysa sanguinea (India); Ferraria cornucephala iwamusi H. Hoshide, 1956, found in Marphysa iwamusi (Japan); and Viviera sp. a species sharing characteristics with Viviera marphysae Schrével, 1963, described in France from Marphysa sanguinea. These gregarines are reported for the first time from this host in Tunisia. Bhatiella marphysae and Viviera sp. belong to the family Lecudinidae (Aseptatorina). Our observations confirm the occurrence of a true septum in Ferraria cornucephala which must be maintained in Polyrhabdinae (Septatorina).

The polychaete Perinereis macropus (Claparède, 1870) (Nereididae) is present in the Gulf of Gabes, but its reproductive biology is unknown. An intensive study was conducted from August 2004 to July 2005 to characterize the life cycle of a population in the mouth of wadi Ferd in Gabes. The examination of sexual products allows us to describe the morphological oocytes aspects at different stages. The results show that P. macropus has an asynchronous oogenesis. Moreover, the biometric study of oocytes growth allows us to clarify the female sexual cycle. The female maturity occurs in April and the mature oocyte diameter is approximately 250+/-32.67 microm. However, spawning occurs in May, when the seawater temperature starts rising. We propose that the reproductive season stretches from March to June in the Gulf of Gabes.

The coastal areas, like the gulf of Tunis, are more and more affected by the increasing anthropic activities and nutriment inputs coming from the catchments area. The polychaeta populations show different reactions in front of such conditions and constitute an effective biological tool to detect the first signs of disturbance. In total, nine stations in the north-east of the gulf, were sampled by the Van Veen grab. In this study, the model of ecological groups and biotic index was used. It appears that the general state in the studied area is overall satisfactory, except for some ones where a situation of beginning of imbalance or of transition, seems taking place. Le golfe de Tunis est expose aux activites anthropiques croissantes exercees par plus de 2 millions d'habitants, telles que les rejets urbains et industriels et aussi aux apports terrigenes conduits par plusieurs oueds. Face a cette situation, les annelides polychetes reagissent differemment et constituent un outil biologique efficace pour deceler les signes de degradation du milieu. Au total, neuf stations reparties le long de la cote Est ont ete echantillonnees a l'aide de la benne Van Veen. Le modele des groupes ecologiques et des indices biotiques a ete employe conjointement avec les indices de biodiversite. Il apparait que l'etat general dans le secteur etudie est globalement satisfaisant, sauf pour certaines zones ou une situation de debut de desequilibre, voire de transition, semble s'installer. Published

International audience

Coupling effects of hydrodynamics and predatory activity of Nepthys hombergii (Savigny) (Polychaeta: Nephtyidae) on emigration of Hediste diversicolor (O.F. Müller) (Polychaeta: Nereidae) recruits were assessed in a flume. Experiments carried out in still water conditions and in the flume flow showed that predatory activity of N. hombergii is independent of the presence or the absence of flow and does not statistically influence the recruit emigration rate. It appears, however, that hydrodynamics is an inhibiting factor for the emigration of H. diversicolor which occurs in the absence of flow. The comparison of these results with literature data suggests that recruits could use hydrodynamics to leave an unsuitable habitat according to the species mobility range.

Hydrothermal communities of various species compositions have been described from the eastern and western Pacific and Atlantic. Brine and cold seeps and hydrocarbon seepages have been found off Florida, off the Oregon and Japanese subduction systems, on the Laurentian Fan, near Barbados, and off Louisiana. Biomasses range from 10 to 70 kg/m super(2), fresh weight. Basic microdistribution of species groups in aureoles centered around hydrothermal vents reveals different levels of adaptation to harsh physico-chemical conditions. Two groups of primary producers can be recognized: a highly efficient cool water group with large vestimentiferan tube worms and bivalves, and alvinellid polychaetes adapted to hot waters. Both groups are exploited by specific carnivores. The food web is based on sulfooxidizing symbiotic bacteria. Methanotrophic symbiotic bacteria have recently been found in bivalves off Louisiana. Nearly 160 species new to sciences have been described, with an abnormally large number of panchronic species. The short life span of hydrothermal vents together with the world-wide distribution of several species raise questions of propagation and colonization.

In Nereis pelagica, graft of dorsal or ventral parts of a regenerate edified in the absence of nerve cord (=aneurogenic) on the ventral or dorsal face of a normal host demonstrates a completely dorsal nature of the body wall in these special regenerates. The results indicate that the nerve cord is involved in setting up regenerate dorso-ventral polarity by fixing differentiation of the ventral characters in the area located near by; without it , only the dorsal character is expressed.

Induction of maturation in Chaetopterus oocytes requires the presence of Ca++ ions in the medium, but differentiation without cleavage can proceed in the absence of this cation. The Ca++ ionophore A 23187 induces both maturation and the cortical reaction provided that Ca++ ions are present in the medium differentiation without cleavage may follow. Valinomycin slowly induces germinal vesicle breakdown, which is followed by a sharp segregation between hyaloplasm and yolk. PHMPS, but not DTT, induces maturation. Differentiation without cleavage is more sensitive to colchicin than to cytochalasin B., English Abstract, Journal Article, info:eu-repo/semantics/published

The first species belongs to the genus Pleurocystis (in the Oligocheta host, Eiseniella tetraedra). It is characterized by early syzygies with lateral connection and navicular sporocysts with similar poles. It differs from the only species already described of the genus and is named Pleurocystis eiseniellae n. sp. The second one is related to the genus Pterospora (in the Polychaeta host, Petaloproctus terricola) but differs from the three species already known by its size and number of terminal digitations in specimens always found in syzygy. The sporocysts with dissimilar poles (one rounded, the other neck-shaped) show a loose epispore. This Gregarine in named Pterospora petaloprocti n. sp.

The reproduction of Nereid Perinereis cultrifera in the English Channel and the Atlantic is of an epitokous type. The same Nereid in the Mediterranean (Bay of Alger) has been described as atokous (Marcel, 1962) and since that time epitoky in mediterranean specimens has been considered to be an accidental phenomenon. However, in the present study polychaetes collected at Salammbô (near Tunis) show that those P. cultrifera reproduce exclusively by epitoky.

3H Trp and 14C Lys incorporation in proteins from chromatin of normal and regenerating animals, purified on metrizamide, show that the synthesis of these proteins is different in the two cases.

The perivasal tissue of some blood vessels (antero-lateral vessels of Pomatoceros triqueter, ventral and lateral vessels of Sabella pavonina) shows a remarkable quantity of iron and pseudo-peroxidase activity. At the EM level, this tissue is characterized by numerous dense DAB positive inclusions and well developed granular endoplasmic reticulum and Golgi. Its function in chlorocruorin synthesis is discussed.

Meiotic maturation is triggered by ionophores A 23187 and X 537 A, even in absence of extracellular calcium. CaMg free medium alone initiates 100% maturations while Ca free SW triggers varying percentages of maturation and Mg free SW has no effect.

The elemental chemical composition of Scolelepis fuliginosa was comparatively with specimens reared in laboratory and from a natural population. The carbon-nitrogen ratio variations show a certain homogeneity of composition in juveniles and young sexed and a sexual dimorphism in adults. C/N ratio of the laboratory specimens is not significantly different from that of the ones from natural surroundings. But, when these are kept several weeks in captivity, this ratio considerably decreases.

An iron rich tissue with an important pseudo-peroxidase activity and which specifically incorporates 55Fe and 3H delta aminolevulinic acid is localized around some vessels of the investigated Annelids : parapodial vessels of Nephthys, chloragogen coeca of Arenicola. This tissue which can be considered as haemopoietic has been studied at the EM level : it is characterized by numerous dense inclusions with pseudo-peroxidase activity and well developed granular endoplasmic reticulum and Golgi.

In Gymnophallidae life-cycle, the primary host is very often a Lamelli-branch, rarely a Prosobranch; the second intermediate host is usually a Pelecypod, rarely a Prosobranch or an Annelid. The first host is generally sedentary; consequently, cercariae are not widely spread. The second intermediate host cannot explore all the environment. These characters are not in favour of the parasite. Adaptation of Gymnophallid cycle consists in a very large cercarial productivity (several millions for only one first host). The recruiting modalities of Gymnophallid larvae by the second intermediate host are not always the same. Two different mechanisms have been discovered. The first one consists of a limited recruiting. The number of metacercariae is not always growing up during the host-life. This number depends on the volume of microhabitat. The top number is reached when microhabitat is saturated. The second one consists of a illimited recruiting. The number of parasites increases during all the second host life. This peculiarity is possible because the metacercariae are permanently carried out of the microhabitat where they had settled. Parasites are indeed progressively surrounded by pallial proliferations and become enclosed inside pockets of host tissues. Thus, microhabitat is always free of parasites and infection can go on. There must be a correlation between the mechanism of the recruitment of Gymnophallid larvae by a given second host and the characteristics of the environment where the life cycle unfolds. In confined environment (almost closed lagoons, brackish ponds) the number of cercariae is very large and the recruitment observed is limited. Then, the host-life is preserved. In wide open stations, where hydrodynamism is important, cercariae are scattered. The recruitment observed is illimited. This peculiarity is probably an adaptative factor permitting concentration of larvae in the second intermediate host.

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In Nereis pelagica, the existence of an additional nerve cord grafted dorsally induces the differentiation on the dorsal face of the regenerate of a supernumerary area with ventral characteristics, provided the grafted nerve cord regenerates posteriorly. These results led us to think that the dorse-ventral differentiation of the body wall doesn't depend upon the nature of the stump region but is controlled by the nerve cord regenerating in the area.

High specific and nonspecific cholinesterase activities have been demonstrated in the whole nervous system of Nereis. These might reveal the existence of a cholinergic nervous system whose control would be exerted in different sites (central nervous centers, muscular junctions...).

Protein and iron concentrations and maximum combined oxygen concentration were measured in the blood of the lugworm Arenicola marina. The calculated mean molecular mass of the heme-associated proteins was higher than that reported for known invertebrate and vertebrate intracellular hemoglobins. The difference is probably due to the presence of polypeptide chains not linked to heme groups in the extracellular annelid hemoglobins.

Within the biometrical study of the Nereidae and in order to characterize the different populations, we looked for the most relevant biometrical characteristics. In fact, for these sea-animals, the weight and length remain just significant statements within certain limits; on the other hand the length of the maxillary, the number of paragnaths which decorate the proboscis can be precisely known.

A quantitative study of elementary granules in neuron axons of the nervous chain of Owenia fusiformis (Annelid polychaete) shows that daily variations of the number of secretory granules occur in unamputated animals and in ventral tissue cultures. These variations are correlated with the thythm of the cell cycle.

Five thousand brains inhibiting gametogenesis in Nereis diversicolor and Perinereis cultrifera were extracted with cold methanol, giving a micromolecular fraction containing the whole of the inhibitory activity of the brains. This micromolecular fraction, fractionated (i) on Sephadex G 25 fine and (ii) on Sephadex G 25 superfine, gave an inhibitory peak (P 5) in organ culture. Fraction P 5, purified by high-pressure liquid chromatography, showed an area with the same biological inhibitory activity as the blank brains.

The longitudinal fibres from atokous Nereis belong to the double oblique striation type. Their thick myofilaments, paramyosinic (about 145 A periodicity) are arranged in an hexagonal lattice, well preserved after a glycerol treatment. 9 to 13 thin filaments form an orbit around one thick filament (ratio: 6-7/1). The contraction occurs in two processes: a sliding filament mechanism, and a shearing mechanism. This second mechanism consists in a parallel shifting of thick filaments, arising their overlap and decreasing their degree of stagger; it induces the increase of the myofibrillar (A-bands) oblique angle from 10-12 degrees in isolated glycerol extracted fibres, to 35-38 degrees in the same fibres after contraction by the action of ATP-solution. The longitudinal fibres from epitokous Nereis or Heteronereis are characterized also by a double oblique striation. The structural aspects of the contraction are similar to these ones occurring in atokous fibres. Nevertheless, the epitokous fibres are different from the atokous fibres by many characteristic points. Their thick myofilaments, with an hexagonous array, are thinner and shorter than these ones from atokous fibres. The contractile material is only present in the cortex. The axis of epitokous fibres is filled with numerous mitochondria, between them numerous glycogen particles have been synthetised. The sarcoplasm of the fiber's coelomic edge is often devoided of myofilaments but it is full of mitochondria and glycogen granules. The nucleus, with a voluminous nucleolus, is no more placed in the fibre axis, but in a lateral sarcoplasm containing ribosomes, glycogen and mitochondria. The important transformations of longitudinal fibres are discussed in connection with the Heteronereis locomotor behaviour, very different from this one of the atokus Nereis. Particularly, it seems that the abundance of glycogen and mitochondria in epitokous muscles allows a high contraction frequency. The decrease of the diameter and length from the thick filaments should be set in relation with the augmentation of the contraction's swiftness. These results are very similar to these ones occuring in Syllidae with the stolonization mode of reproduction. The Syllis stolonial fibres present the same characteristics than the Nereis epitokous fibres.

The present studies show the presence of a singular structure: a myoepithelial syncytium with the bases of the cells being embedded in a hypertrophied basal lamina containing collagen, in which bundles of muscular fibers also penetrate. The cells forming a vascular pseudo-endothelium are probably immobilised haemocytes.

Two histophysical methods (electron microprobe and ion microanalyzer) were used on sections of Annelids in order to study the inorganic composition of cement secretory glands. Mg, Ca and P were demonstrated in large amounts in the secretions, associated with organic matter. Traces, or no, Fe, Al and Si were found. Possibilities of artifacts are discussed, and these results are compared with biochemical methods. A hypothesis is proposed in order to explain the differences observed between biochemical and present results, which suggest, for the hardening of cements a different chemical mechanism to that suggested by Vovelle in annelid Sabellaria alveolata.

Cholinergic synaptosomes were depolarized with KCl or treated with a venom extracted from the annelid Glycera convoluta. This venom was shown to increase considerably the frequency of the miniature endplate potentials at neuromuscular junctions. The synaptosomes were frozen and fractured in the absence of any fixative or cryoprotectant. Synaptic activity decreased the number of small (6 to 8 nm) particles in the P faces of the presynatic membrane, while the large particles (above 8 nm) increased on both P and E faces. It is suggested that these modifications are related to ionic flux or more directly to the release of transmitter.