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SYNOPTIC DESCRIPTION OF THE PHYLUM LABYRINTHOMORPHA

SYNOPTIC DESCRIPTION OF THE PHYLUM LABYRINTHOMORPHA (LEVINE ET AL. 1980)

EUKARYA> CHROMALVEOLATA> HETEROKONTAE> LABYRINTHULOMORPHA
LABYRINTHOMORPHA LINKS

Introduction

Hierarchical Classification

The following description comes from Margulis and Schwartz (1988 and 1998), Kudo (1966), Grell (1976), Patterson (1999), and Porter (1990).

I. SYNONYMS: Slime nets and thraustochytrids.

II. NUMBER: >25 species.

III. PHYLUM CHARACTERISTICS:

  • A. Structure and Physiology
    • Cell Form: Spindle-shaped cells within slime nets formed by bothrosomes (text with tooltip) Bothrosomes (sagenogen, sagengenetosomes) are organelles on the cells of labyrinthulids which produces the slime web. (sagenetosomes).
    • Flagella: Gametes have two flagella, one anteriorly-directed (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. and one 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. and 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. .
    • Basal Bodies: Perpendicular (text with tooltip) Basal bodies are perpendicular (or orthogonal) when their orientation relative to each other is at a right angle. .
    • Cell Covering: Feeding cells naked, secreting slime outer covering.
    • Chloroplasts: Not present.
    • Food Reserves: Not known.
    • Mitochondria: Tubular cristae (text with tooltip) Mitochondrial cristae that form as extended saccate structures or tubes are called tubular cristae. .
    • Golgi: Present.
    • Nucleus: Cells uninucleate with prominent central nucleolus.
    • Centrioles: Present and contain an elongate core of dense material.
    • Inclusions and Ejectile Organelles: Not present.
  • B. Mitosis, Meiosis and Life History
    • Mitosis: Details not known.
    • Meiosis: Leads to formation of zoospores (text with tooltip) A zoospore is an asexual spore that is motile. Zoo- (pronoumced zo-o) is a prefix that means moving. .
    • Sexual Reproduction and Life History: Meiosis forms zoospores which settle down and form the net; fusion of vegetative cells in the net (?) forms enlarged cells which undergo meiosis; can form cysts in response to desiccation.
  • C. Ecology: Marine, feeding on or parasitic on algae and grasses.
LITERATURE CITED

Alexopoulos, C. J. and C. W. Mims. 1979. Introductory Mycology. 3rd ed. John Wiley and Sons. New York.

Baldauf, S. L. 2003a. The deep roots of eukaryotes. Science. 300 (5626): 1701-1703.

Grell, K. G. 1973. Protozoology. Springer-Verlag. New York.

Kudo, R.R. 1966. Protozoology. 5th ed. Charles C. Thomas Publisher. Springfield.

Leipe D. D., S. M. Tong, C. L. Goggin, S. B. Slemenda, N. J. Pieniazek, and M. L. Sogin. 1996. 16S-like rDNA sequences from Developayella elegans, Labyrinthuloides haliotidis, and Proteromonas lacertae confirm that the stramenopiles are a primarily heterotrophic group. European Journal of Protistology. 32: 449-458.

Leipe, D. D., P. O. Wainright, J. H. Gunderson, D. Porter, D. J. Patterson, F. Valois, S. Himmerich, and M. L. Sogin. 1994. The stramenopiles from a molecular perspective: 16S-like rRNA sequences from Labyrinthuloides minuta and Cafeteria roenbergensis. Phycologia. 33:369-377.

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.

Pokorny, K.S. 1985. Phylum Labyrinthomorpha. In: Lee, J.J., S.H. Hunter, and E.C. Bovee, eds. An Illustrated Guide to the Protozoa. Allen Press. Lawrence , Kansas . pp. 318-321.

Porter, D. 1990. Labyrinthulomycota. 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. 388-398. [L]

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: 02/25/2012
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