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Introduction
Publications
Publications (51)
Nautilus is one of the most intriguing of all sea creatures, sharing morphological similarities with the extinct forms of coiled cephalopods that evolved since the Cambrian (542-488 mya). Further, bacterial symbioses found in their excretory organ are of particular interest as they provide a great opportunity to investigate the influence of host-mi...
Trawl surveys off Western Australia and seamounts south of New Caledonia at depths between 375 and 545 m have yielded two species of a previously unknown genus of benthic octopus (Family: Octopodidae). Histoctopus n. gen. is described here and contains two new species, Histoctopus discus and Histoctopus zipkasae n. spp. The most distinctive morphol...
In Octopus, the caecum, the pancreas and the liver are involved in the absorption of 3H-glycine-labelled food. The caecum exhibits the highest specific activity while the liver absorbs the largest proportion of labelled material. The administration of stained food shows in vivo alternating phases of absorption and secretion in the liver and continu...
The concentrations of 16 trace elements were investigated and compared for the first time in the digestive and excreting tissues of two Nautilus species (Cephalopoda: Nautiloidea) from two geologically contrasted areas: (1) N. macromphalus from New Caledonia, a region characterized by its richness in nickel ores and its lack of tectonic activities...
The aim of the present study was to identify and characterize bacteria producing antimicrobial compounds in the excretory
organs of Nautilus pompilius. Culture-dependent and culture-independent complementary approaches were used for bacterial identification such as: culture
on selective media, Gram staining, CARD-FISH, direct DNA extraction from ho...
Symbiosis is an important driving force in metazoan evolution and the study of ancient lineages can provide an insight into the influence of symbiotic associations on morphological and physiological adaptations. In the 'living fossil' Nautilus, bacterial associations are found in the highly specialized pericardial appendage. This organ is responsib...
The recent application of molecular tools to address associations between bacteria and marine invertebrates has provided access
to an immense diversity of unidentified microbes resistant to cultivation. However, the role of bacteria as partners in animal
physiology remains unclear and in most cases difficult to investigate in the absence of adequat...
A new genus and species, Choneteuthis tongaensis gen. et sp. nov., is described from the waters around Tonga in the central South Pacific Ocean. The new genus does not clearly fit in any of the currently recognized subfamilies of the family Sepiolidae, justifying a reconsideration of the subfamilial subdivision of the family.
The sepiids are characterized by their cuttlebone or sepion, an internal shell resulting from secondary mineralization of a chitinous ‘gladius’. The various species are identified using a combination of shell criteria and ‘soft-part’ characters. Using mitochondrial genes, we established phylogenetic relationships of sepiids including the three acce...
Deep-water trawl surveys on seamounts around New Caledonia yielded 62 specimens of the little-known genus, Scaeurgus. Members of this genus of octopuses typically occur at depths of 200–500 m in temperate and tropical latitudes worldwide.
Prior to this study, Scaeurgus was considered to contain one to two species. The new material from New Caledoni...
Bacterial communities were identified from the accessory nidamental glands (ANGs) of European and Western Pacific squids of
the families Loliginidae and Idiosepiidae, as also in the egg capsules, embryo and yolk of two loliginid squid species, and
in the entire egg of one idiosepiid squid species. The results of phylogenetic analyses of 16S RNA gen...
The accessory nidamental glands (ANG) of sepiids and loliginids harbour a dense population of bacteria of unknown functions. The α-proteobacterium Roseobacter is present in most species. The present results show that 3 Roseobacter strains are associated with the cephalopod ANG. Two strains are specific to cephalopod taxa, the third is grouped toget...
The taxonomic and phylogenetic position of Idiosepius among Decabrachia is reconsidered, based on cephalopod partial gene sequencing and on accessory nidamental gland symbiotic bacteria DNA analyses. Phylogenetic trees are established from partial ribosomal mitochondrial genes (16S rDNA and 12S rDNA) and cytochrome oxidase genes (CO I and CO III):...
Microeledone mangoldi n. gen. and n. sp. is described from a male specimen collected from approximately one kilometre deep on the Norfolk Ridge south of New Caledonia in the south-west Pacific Ocean. This tiny octopus is characterised by a single row of suckers that are functional to the tips of the arms, the absence of an ink sac, the presence of...
Nautiloids, the externally shelled cephalopods of Cambrian origin, are the most ancient lineage among extant cephalopods. Their ancestral characters are explored based on morphological and molecular data (18S rDNA sequence) to investigate the evolution of present cephalopod lineages. Among molluscs, nautilus 18S rDNA gene is the longest reported so...
Cephalopod phylogeny has been explored using part of 28S and 18S ribosomal nuclear genes in a number of coleoid (mainly decapod) and nautiloid species. Two regions of 28S rRNA gene were sequenced: (C1/D1/C2) and (D2). If the first region is unsuitable to discriminate groups of coleoids, the second one, more variable, is more informative and allows...
Human bothriocephalosis is once again being found in various catchment basins in the subalpine region, including Lago Mag- giore and Lac Léman, which however are not isolated cases. Domestic animals are thought to be responsible for the survival of the parasite during the period when no human cases were reported. The new phenomenon of eating raw or...
Soils in New Caledonia are particularly rich in metals among which Fe and Ni are intensively exploited. Due to important natural erosion in tropical latitudes and to mining activities, coastal waters are enriched in Co, Cr, Fe and Ni. In deeper waters lives a cephalopod species which is considered as a living fossil, the nautilus Nautilus macrompha...
Wolfgang Geiger died on the 3rd July 2000, at the age of 79. He was born on July 17th 1921 in Biel; his mother died at his birth. His childhood was spent with his father, a well-known artist, partly in Ligerz, on Lake Biel, and partly in Porto Ronco in Ticino, on Lago Maggiore. After high school in Biel, he began his University studies, first at th...
Female cuttlefish harbour a dense bacterial community in their accessory nidamental glands (ANG), as is also the case for
the myopsid squids. Molecular approaches have been applied to explore this symbiotic association in the sepiid species Sepia officinalis. In situ localisation by Bacteria-specific probes in tissue sections of the ANG revealed t...
The oegopsid squid family Onychoteuthidae presently comprises six genera (Moroteuthis, Onychoteuthis, Ancistroteuthis, Kondakovia, Onykia and Chaunoteuthis) but the status of some of these is still uncertain. An interdisciplinary study was undertaken to clarify the phylogenetic relationships, which included a morphological approach (morphometric an...
Sequences of partial mitochondrial cytochrome oxidase III gene (533 bp) were obtained for 17 species of cephalopods, 14 decapods, 2 octopods, and 1 vampyromorph. This study aimed to: (1) compare partial COII and COIII amino acid sequences of three species of cephalopods with other invertebrates in terms of base composition and phylogenetic relation...
Cephalopod taxonomy is still uncertain, and little is known of the phylogeny of Recent taxa. Biochemical and molecular characters are complementary to morphology, and allow an additional insight into the phylogenetic relationships among cephalopods. Eye lens protein electrophoresis and immunological approaches yield data in agreement with tradition...
Phylogenetic relationships for extant cephalopods have been based, so far, mainly on morphology and paleontology. Nucleotide sequence data are still rare. Sequence analyses from the 3' end of the 16S rDNA gene of cephalopods have shown that this portion of gene can provide valuable information on taxonomic relationships at the infrafamilial level....
Various systematic and phylogenetic relationships have been proposed for extent decapod Cephalopods, based mainly on morphology and on the rare paleontological remains. Nucleotide sequence data from the 3' end of 16S rDNA gene were used as an alternative approach to morphology; this gene portion having proved to be appropriate to test divergences i...
Respiration and calcification were investigated in the ectocochleate cephalopod Nautilus macromphalus Sowerby. Specimens were collected off New Caledonia, in October 1991, and kept at the Nouma Aquarium until December 1991. The respiratory quotient and calcification rate of 5 individuals were measured during 14 short term incubations (63 to 363 min...
Oxygen consumption and dissolved nitrogen fluxes at the water-sediment interface of an oyster-bed were measured in situ using transparent enclosures inserted on undisturbed sediment. Experiments were performed in summer, under dark and light conditions, with various densities of the oyster Crassostrea gigas (0–150 animals m – 2). The influence of o...
Respiration and nitrogen excretion rates of mature adult Loligo forbesi were investigated at the Roscoff Laboratory (North Brittany, France) during individual short-term incubation experiments in January 1986. The squids were in post-digestive condition and not actively swimming. Both oxygen uptake and nitrogen excretion are continuous processes. T...
The digestive organs possibly involved in food absorption in Loligo vulgaris and L. forbesi are the caecum, the intestine, the digestive gland, and the digestive duct appendages. The histology and the fine structure showed that the ciliated organ, the caecal sac, and the intestine are lined with a ciliated epithelium. The ciliary rootlets are parti...
Ammonia excretion was investigated in relation to oxygen consumption during a feeding regime and during shortterm starvation in two mature male Octopus vulgaris, trawled in spring 1983 off Banyuls-sur-mer. In our study, ammonia excretion is taken to include renal and gill loss. The excretion of primary amines was also studied, but proved to be negl...
The importance of short-term fluctuations in nutrients and primary amines over oyster beds during spring and neap tidal cycles was analysed. The range of the variations recorded over 24 h is of the same order of magnitude as that observed over an annual cycle.
Multivariate analysis, taking into account all available parameters concerning the tidal...
In the benthic octopus Octopus cyanea Gray, acclimated to high temperature (30°C), digestion takes 12 h. Animal weight and food intake do not influence the duration of digestion. By regulating the rate of food passage in the alimentary canal, the quantity of digested food (as a percentage of ingested food) is kept constant at a particular time. A c...
