Abstract
The ultrastructure of the epidermis of Meara stichopi Westblad, an endosymbiont in the holothurian Parastichopus tremulus (Gunneri) was studied. The entire body surface of the worm is ciliated. The columnar epithelial cells interdigitate with each other. The epidermal cells are not insunk and have a prominent terminal web underlined by mitochondria. Each cilium has a main, anteriorly pointing, cross-striated rootlet with a knee and a posterior rootlet dividing into two lateral fibre bundles. These bundles descend to contact the two neighbouring rootlets in the row behind. The basal bodies contain glycogen granules. Epidermal glands containing secretion globules are common. Some epidermal glands contain rhabdoids.
Between the epidermal cilia we found elongated procaryotic organisms, evidently symbiotic gram-negative bacteria, anchored with a tapering end in the glycocalyx.
The observations imply that the ultrastructure of the epidermis of M. stichopi is similar to that described earlier from Nemertoderma and Flagellophora (Nemertodermatida). Thus these three genera share some systematically interesting ultrastructural character states, especially the pattern of the ciliary rootlet system.
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References
Ax, P., 1984. Das phylogenetische System. Systematisierung der lebenden Natur aufgrund ihrer Phylogenese. G. Fischer, Stuttgart, New York, 349 pp.
Bedini, C. & F. Papi, 1974. Fine structure of the turbellarian epidermis. In N. W. Riser & M. P. Morse (eds), Biology of the Turbellaria, McGraw Hill, New York, St. Louis, etc.: 108–147.
Dorey, A. E., 1965. The organization and replacement of the epidermis in acoelous turbellarians. Q. J. Microsc. Sci. 106: 147–142.
Ehlers, B. 1977. `Trematoden-artige’ Epidermisstrukturen bei einem freilebenden proseriaten Strudelwurm (Turbellaria, Proseriata). Acta zool. Fenn. 154: 129–136.
Ehlers, U., 1985. Das phylogenetische System der Plathelminthes. G. Fisher, Stuttgart, New York, 317 pp.
Ehlers, U., 1992a. On the fine structure of Paratomella rubra Rieger & Ott (Acoela) and the position of the taxon Paratomella Di5rjes in a phylogenetic system of the Acoelomorpha (Plathelminthes). Microfauna Marina 7: 265–293.
Ehlers, U., 1992b. Frontal glandular and sensory structures in Netnertoderina (Nemertodermatida) and Paratomella (Acoela):ultrastructure and phylogenetic implications for the monophyly of the Euplathelminthes (Plathelminthes). Zoomorphology 112: 227–236.
Hendelberg, J., 1976. Granules of glycogen beta-particle type demonstrated in epidermal ciliary rootlets of acoelous turbellarians. J. Ultrastruct. Res. 54: 491.
Hendelberg, J., 1977. Comparative morphology of turbellarian spermatozoa studied by electron microscopy. Acta zool. Fenn. 154: 149–162.
Hendelberg, J., 1981. The system of epidermal ciliary rootlets in Turbellaria. Hydrobiologia 84: 240.
Hendelberg, J., 1986. The phylogenetic significance of sperm morphology in the Platyhelminthes. Hydrobiologia 132 (Dev. Hydrobiol. 32): 53–58.
Hendelberg, J. & K.-O. Hedlund, 1973. Electron microscope studies of the junctions between ciliary rootlets and the orientation the ciliary axonemes in the epidermis of acoelous turbellarians. J. Ultrastruct. Res. 44: 440.
Hendelberg, J. & K.-O. Hedlund, 1974. On the morphology of the epidermal ciliary rootlet system of the acoelous turbellarian Childia groenlandica. Zoon. 2: 13–24.
Karling, T. G., 1974. On the anatomy and affinities of the turbellarian orders. In: N. W. Riser & M. P. Morse (eds), Biology of the Turbellaria. New York: McGraw-Hill; 1–16.
Mamkaev, Yu. V., 1991. On the phylogenetic significance of sagittocysts and copulatory organs in acoel turbellarians. Hydrobiologia 227 (Dev. Hydrobiol. 69): 307–314.
Rieger, R. M., 1981. Morphology of the Turbellaria at the ultrastructural level. Hydrobiologia 84: 213–229.
Rieger, R. M., S. Tyler, J. P. S. Smith & G. E. Rieger, 1991. Platyhelminthes: Turbellaria. In F. W. Harrison (ed.), Microscopic Anatomy of Invertebrates, 3. Wiley-Liss, N.Y.: 7–140.
Rohde, K., N. Watson & L. R. G. Cannon, 1988. Ultrastructure of epidermal cilia of Pseudactinoposthia sp. (Platyhelminthes, Acoela); implications for the phylogenetic status of the Xenoturbellida and Acoelomorpha. J. Submicrosc. Cytol. Pathol.: 20: 759–767.
Silveira, M., 1972. Association of polysaccharid material with certain flagellar and ciliary structures in turbellarian flatworms. Revue Microsc. Electron. 1: 96.
Smith, J. P. S., 1981. Fine-structural observations on the central parenchyma of Convoluta sp. Hydrobiologia 84: 259–265.
Smith, J. P. S., S. Tyler & R. Rieger, 1986. Is the Turbellaria poly-phyletic? Hydrobiologia 132 (Dev. Hydrobiol. 32): 13–21.
Smith, J. P. S., S. Tyler, M. B. Thomas & R. M. Rieger, 1982. The morphology of turbellarian rhabdites: phylogenetic implications. Trans. am. Microsc. Soc. 101: 209–228.
Sopott-Ehlers, B. 1989. Zur Ultrastruktur von Bulbotoplana acephala Ax (Proseriata, Plathelminthes). Microfauna Marina 5: 219–226.
Tyler, S., 1979. Distinctive features of cilia in metazoans and their significance for systematics. Tissue Cell 11: 385–400.
Tyler, S & R. M. Rieger, 1977. Ultrastructural evidence for the systematic position of the Nemertodermatida (Turbellaria). Acta Zool. Fenn. 154: 193–207.
Westblad, E., 1949. On Meara stichopi (Bock) Westblad, a new representative of Turbellaria archoophora. Ark. Zool. 1: 43–57.
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Lundin, K., Hendelberg, J. (1995). Ultrastructure of the epidermis of Meara stichopi (Platyhelminthes, Nemertodermatida) and associated extra-epidermal bacteria. In: Cannon, L.R.G. (eds) Biology of Turbellaria and some Related Flatworms. Developments in Hydrobiology, vol 108. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-0045-8_27
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DOI: https://doi.org/10.1007/978-94-011-0045-8_27
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