SYNOPTIC DESCRIPTION OF THE PHYLUM EUSTIGMATOPHYTA (HIBBERD & LEEDALE 1970)
| EUKARYA> CHROMALVEOLATA> HETEROKONTAE> EUSTIGMATOPHYTA |
EUSTIGMATOPHYTA LINKS
| The following description of the phylum comes from Bold and Wynne (1985); Sze (1986); Lee (1980 &1989), Graham and Wilcox (2000), Margulis and Schwartz (1988 and 1998), Sleigh et al. (1984), Hibberd (1990b), and Van den Hoek (1995). |
I. SYNONYM: Eustigs.
II. NUMBER: 12 species (7 genera).
III. PHYLUM CHARACTERISTICS:
- A. Structure and Physiology
- Cell Form: Organisms coccoid.
- Flagella: Never found in vegetative forms. Two flagella; recurrent (text with tooltip) Recurrent flagella bend to the posterior end of the cell. Typically, they are identified as recurrent when anteriorly-directed flagella are present. or posterior whiplash (text with tooltip) (1) A whiplash flagellum is a eukaryotic 9+2 flagellum with few or no flagellar hairs or scales. These may be directed anteriorly or posteriorly. (2) A whiplash flagellum is free of hair-like mastigonemes and usually is trailing or posteriorly-directed. and anterior (text with tooltip) An anteriorly-directed flagellum extends in the direction of the motion of the motile cell. The interpretation is that the flagellum functions by pulling the cell. tinsel (text with tooltip) A tinsel flagellum is one that is covered with flagellar hairs and thus appears thicker in light microscopy. Usually, tinsel flagella are anteriorally-directed. with two rows of thick mastigonemes (text with tooltip) Mastigonemes are flagellar hairs. ; often whiplash flagellum missing. Flagellar swelling (text with tooltip) A flagellar swelling is a portion of the base of a flagellum that usually is light sensitive (as in the eyespot apparatus of euglenoids). at the base of the tinsel flagellum and associated with an eyespot (text with tooltip) An eyespot is a light-sensitive structure that does not form an image. This can be part of an organelle as in the chloroplast of certain microbial eukaryotes. It can be an elaborate structure that involves a light-sensitive swelling at the base of a flagellum (as in the euglenoids) or it can be a multicellular structure as in planarians. .
- Basal Bodies: Basal bodies (text with tooltip) Basal bodies (also called kinetosomes) are organelles that are not membrane-bound. All eukaryotic flagella (also called undulipodia) are underlain or attached to the cell by the basal body. The basal body is a microtubular structure with the general formula 9(3)+0. They are indistinguishable from centrioles. perpendicular and with rhizoplast (text with tooltip) A rhizoplast is a striated root system that extends from the basal body tinto the cell, usually to the nuclear envelope. .
- Cell Covering: Of one piece, composition unknown.
- Chloroplasts: Numerous yellow-green chloroplasts with chlorophylls a (text with tooltip) Chlorophyll A is a primary photosynthetic pigment of all photosynthetic eukaryotes (in the chloroplasts) and Cyanobacteria. It is membrane-bound on thyllakoids and absorbs mainly in the blue and red ranges of visible light. Its structure is that of a tetrapyrrole with a magnesium in the center. That is bound to a long aliphatic alcohol (phytol). Chlorophylls a, b, c, d, and e, together with the bacteriochlorophylls have similar structures and vary only in the structures of their side chains. , c1, and c2 (text with tooltip) Chlorophyll C is a variant of Chlorophyll A. and a secondary photosynthetic pigment in the many of the photosynthetic heterokonts and dinoflagellates. (e?); also with B-carotene, and some xanthophylls (text with tooltip) Xanthophyll is an oxygenated carotenoid secondary photosynthetic pigment that occurs in many of the photosynthetic eukaryotes. which are not found in the xanthophytes; a large eyespot situated within the cytoplasm at the anterior end of the cell. Polyhedral pyrenoid (text with tooltip) A polyhedral pyrenoid is a pyrenoid (photosynthate assembly center that occurs in a chloroplast) that is angular in form. on inner surface of the chloroplast.
- Food Reserves: A glucose polysaccharide (not yet characterized).
- Mitochondria: Tubular cristae (text with tooltip) Mitochondrial cristae that form as extended saccate structures or tubes are called tubular cristae. .
- 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: Details not known, but associated with a rhizoplast.
- Centrioles: Not reported.
- Inclusions and Ejectile Organelles: Red eyespot.
- B. Mitosis, Meiosis and Life History
- Mitosis: Not described.
- Meiosis: Not reported.
- Sexual Reproduction and Life History: Not reported.
- C. Ecology: Mainly found in fresh water but some in soil and marine plankton.
| LITERATURE CITED Bold, H. C. and M. J. Wynne. 1985. Introduction to the Algae. 2nd Edition. Prentice-Hall, Inc. Englewood Cliffs. NJ. Cavalier-Smith, T. and E. E. Chao. 1996. 18S rRNA sequence of Heterosigma carterae (Raphidiophyceae) and the phylogeny of heterokont algae (Ochrophyta). Phycologia. 35: 500-510. Dodge, J. D. 1973. The fine structure of algal cells. Academic Press. New York. Graham, L. E., and L. W. Wilcox. 2000, Algae: Prentice Hall, Upper Saddle River, NJ. Hibberd, D. J. 1990b. Eustigmatophyta. 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. 326-333. Hibberd, D. J. and G. F. Leedale. 1970. Eustigmatophyceae – a new algal class with unique organization of the motile cell. Nature. 225: 759-760. Lee, R. E. 1980. Phycology. Cambridge University Press. Cambridge. Lee, R. E. 1995. Phycology. 2nd Edition. Cambridge University Press. Cambridge. Lee, R. E. 1999, Phycology: 3rd ed., CambridgeUniversity Press, Cambridge, UK. 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. 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. Sze, P. 1986. A Biology of the Algae. Wm. C. Brown Publishers. Dubuque, Iowa. Taylor, F. J. R. 1976. Flagellate Phylogeny: A Study in Conflicts. J. Protozool. 23: 28-40. Van Den Hoek, C., D. G. Mann, and H. M. Jahns. 1995. Algae, an introduction to phycology. Cambridge University Press. Cambridge. |
| By Jack R. Holt. Last revised: 02/28/2012 |
