SYNOPTIC DESCRIPTION OF THE PHYLUM OPALINATA (WENYON 1926)
| EUKARYA> CHROMALVEOLATA> HETEROKONTAE> OPALINIDA |
OPALINATA LINKS
| The following description comes from Margulis and Schwartz (1988 and 1998), Kudo (1966), Grell (1976), Lynn and Small (1985), Corliss (1990), and Brugerolle and Mignot (1990). |
I. SYNONYMS: Opalinids, protociliates, paraflagellates.
II. NUMBER: >400 species.
III. PHYLUM CHARACTERISTICS:
- A. Structure
- Cell Form: Unicellular; cells flattened.
- Flagella: Opalinid cells covered by short, uniform flagella ( cilia (text with tooltip) Cilia are eukaryotic flagella that operate by coordinated beats relative to each other. Structurally, cilia and flagella are identical (i.e. 9+2 axoneme from a basal body with associated flagellar roots). Usually cilia are shorter and more numerous than typical flagella. Also, they have an underlying structure of flagellar roots (kineties) that allow for coordination of the flagella. ) in oblique longitudinal rows called kineties (text with tooltip) Kineties (kinety) provide the underlying structure of flagellar roots found in ciliates (and others like the pseudociliata) and allow for coordination of the flagella. ; additional kineties may be added during growth at a differentiated region of one anterior margin, the falx (text with tooltip) A falx is a specialized region of pellicle in opalinids. It seems to be a region of kinetid formation as the cell enlarges. . Proteromonads are biflagellate and heterokont, and the anteriorly-directed flagellum has a small paraflagellar rod; the recurrent flagellum is whiplash.
- Basal Bodies: Basal bodies (text with tooltip) Basal bodies are parallel when their orientation relative to each other is parallel. parallel and connected by a microtubular array which is different from that of the ciliates. Proteromonads have perpendicular basal bodies.
- Cell Covering: Pleated pellicle (text with tooltip) A pellicle is a complex outer cellular covering that occurs within the bounds of the plasmalemma. Often synonymous with the term theca, a pellicle defines such groups as the euglenoid-kinetoplastid clade amd the Kingdom Alveolatae. ; no cytostome (text with tooltip) Cytostome (literally cell mouth) is a permanent opening into the cell into which food particles move and are incorporated into food vacuoles. , but proteromonads have a rhizoplast.
- Chloroplasts: Not present.
- Food Reserves: Not reported.
- Mitochondria: Tubular cristae (text with tooltip) Mitochondrial cristae that form as extended saccate structures or tubes are called tubular cristae. . Mitochondria not present in some taxa, especially Blastocystis.
- Golgi (text with tooltip) Golgi apparatus (also called dictyosome) is an internal membrane system of stacked flattened sacs. They occur in nearly all eukaryotes and are involved in storing and secreting cellular products. : Present.
- Nucleus: Opalinids: two to hundreds per cell; isomorphic; with distinct nucleoli. Proteromonads have a single nucleus that is associated with a mitochondrion.
- Centrioles: Absent.
- Inclusions and Ejectile Organelles: Not present.
- B. Mitosis, Meiosis and Life History:
- Mitosis: Promitotic (text with tooltip) Promitotic (adj.) mitosis occurs in closed mitotic systems with an intrnuclear spindle and a persistent nucleolus. with an intranuclear spindle (text with tooltip) An intranuclear spindle elaborates within the nuclear membrane of an organism with closed mitosis. and a nuclear envelope which remains intact; cytokinesis longitudinal or transverse.
- Meiosis: Present.
- Sexual Reproduction and Life History: Opalinid diploids with gametic meiosis (text with tooltip) Gametic meiosis occurs when gametes are the immediate results of meiosis. ; no conjugation.
- C. Ecology: Opalinids: endosymbiotic in digestive tracts of amphibians and fish. Proteromonads endosymbionts of amphibians, reptiles, and mammals (especially rodents)
| LITERATURE CITED Baldauf, S. L. 2003a. The deep roots of eukaryotes. Science. 300 (5626): 1701-1703. Corliss, J.O. 1990. Opalinta. In: Margulis, L., J.O. Corliss, M. Melkonian, and D.J. Chapman, eds. 1990. Handbook of the Protoctista; the Structure, Cultivation, Habits and Life Histories of the Eukaryotic Microorganisms and Their Descendants Exclusive of Animals, Plants and Fungi. Jones and Bartlett Publishers. Boston . pp. 239-245. Grell, K. G. 1973. Protozoology. Springer-Verlag. New York. Kudo, R.R. 1966. Protozoology. 5th ed. Charles C. Thomas Publisher. Springfield. Lynn, D. H. and E. B. Small. 1990. Ciliophora. In: Margulis, L., J. O. Corliss, M. Melkonian, and D. J. Chapman, eds. 1990. Handbook of the Protoctista; the structure, cultivation, habits and life histories of the eukaryotic microorganisms and their descendants exclusive of animals, plants and fungi. Jones and Bartlett Publishers. Boston. pp. 498-523. Margulis, L. and K. Schwartz. 1988. Five kingdoms, an illustrated guide to the phyla of life on earth. 2nd Edition. W.H. Freeman and Co. New York. Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Company. New York. Patterson, D. J. 1989. Stramenopiles: chromophytes from a protistan perspective. In: Green, J. C., B. S. C. Leadbeater, and W. L. Diver, eds. The chromophyte algae, problems and perspectives. Systematics Association Special Volume No. 38. Clarendon Press. Oxford. pp. 357-379. Patterson, D. J. 1999. The diversity of eukaryotes. American Naturalist. 154 (Suppl.): S96–S124. Sleigh, M.A., J.D. Dodge and D.J. Patterson. 1984. Kingdom Protista. In: Barnes, R.K.S., ed. A Synoptic Classification of Living Organisms. Sinauer Associates, Inc. Sunderland, Mass. Sogin, M. L. and D. J. Patterson. 1995. Stramenopiles. Version 01 January 1995 (under construction). http://tolweb.org/Stramenopiles/2380/1995.01.01 In: The Tree of Life Web Project, http://tolweb.org/ |
| By Jack R. Holt. Last revised: 02/23/2012 |
