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1 UPR CNRS 4601, URM IFREMER No 7, Laboratoire de Biologie Marine, UPMC, 7 Quai St Bernard, Bat A, Paris, France
2 Institut de Zoologie, Université de Liège, 22 Quai Van Beneden, B-4020 Liège, Belgium
The structure and chitin-protein content of the tubes of different vestimentiferan species are compared. Riftia pachyptila and Tevnia jerichonana were collected at a hydrothermal vent site at 13°N on the East Pacific Rise; Ridgeia piscesae was from a hydrothermal vent site on the Juan de Fuca Ridge and Lamellibrachia sp. came from a cold seep on the Louisiana continental slope in the Gulf of Mexico. The tube ultrastructure shows chitin microfibrils organized in parallel bundles with various orientations. The chitin content varies considerably between species and is unrelated to seep or vent origin, whereas the protein content is much higher in the cold seep species than the hydrothermal vent species. All the species have specialized chitin secreting glands, as described for R. pachyptila. Based on this investigation, a tentative model of tube morphogenesis under cell control is proposed.